An order or request for both supply of the medication and the instructions for administration of the medication to a patient. The resource is called "MedicationRequest" rather than "MedicationPrescription" or "MedicationOrder" to generalize the use across inpatient and outpatient settings, including care plans, etc., and to harmonize with workflow patterns.

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

An Extension

• value @ url

An Extension

An Extension

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Identifiers associated with this medication request that are defined by business processes and/or used to refer to it when a direct URL reference to the resource itself is not appropriate. They are business identifiers assigned to this resource by the performer or other systems and remain constant as the resource is updated and propagates from server to server.

This is a business identifier, not a resource identifier.

A code specifying the current state of the order. Generally, this will be active or completed state.

This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

Captures the reason for the current state of the MedicationRequest.

This is generally only used for "exception" statuses such as "suspended" or "cancelled". The reason why the MedicationRequest was created at all is captured in reasonCode, not here.

Whether the request is a proposal, plan, or an original order.

It is expected that the type of requester will be restricted for different stages of a MedicationRequest. For example, Proposals can be created by a patient, relatedPerson, Practitioner or Device. Plans can be created by Practitioners, Patients, RelatedPersons and Devices. Original orders can be created by a Practitioner only.

An instance-order is an instantiation of a request or order and may be used to populate Medication Administration Record.

This element is labeled as a modifier because the intent alters when and how the resource is actually applicable.

Indicates the type of medication request (for example, where the medication is expected to be consumed or administered (i.e. inpatient or outpatient)).

The category can be used to include where the medication is expected to be consumed or other types of requests.

Indicates how quickly the Medication Request should be addressed with respect to other requests.

If true indicates that the provider is asking for the medication request not to occur.

If do not perform is not specified, the request is a positive request e.g. "do perform".

Indicates if this record was captured as a secondary 'reported' record rather than as an original primary source-of-truth record. It may also indicate the source of the report.

Identifies the medication being requested. This is a link to a resource that represents the medication which may be the details of the medication or simply an attribute carrying a code that identifies the medication from a known list of medications.

If only a code is specified, then it needs to be a code for a specific product. If more information is required, then the use of the Medication resource is recommended. For example, if you require form or lot number or if the medication is compounded or extemporaneously prepared, then you must reference the Medication resource.

• type @ $this

Identifies the medication being requested. This is a link to a resource that represents the medication which may be the details of the medication or simply an attribute carrying a code that identifies the medication from a known list of medications.

If only a code is specified, then it needs to be a code for a specific product. If more information is required, then the use of the Medication resource is recommended. For example, if you require form or lot number or if the medication is compounded or extemporaneously prepared, then you must reference the Medication resource.

A link to a resource representing the person or set of individuals to whom the medication will be given.

The subject on a medication request is mandatory. For the secondary use case where the actual subject is not provided, there still must be an anonymized subject specified.

The Encounter during which this [x] was created or to which the creation of this record is tightly associated.

This will typically be the encounter the event occurred within, but some activities may be initiated prior to or after the official completion of an encounter but still be tied to the context of the encounter." If there is a need to link to episodes of care they will be handled with an extension.

Include additional information (for example, patient height and weight) that supports the ordering of the medication.

The date (and perhaps time) when the prescription was initially written or authored on.

The individual, organization, or device that initiated the request and has responsibility for its activation.

The specified desired performer of the medication treatment (e.g. the performer of the medication administration).

Indicates the type of performer of the administration of the medication.

If specified without indicating a performer, this indicates that the performer must be of the specified type. If specified with a performer then it indicates the requirements of the performer if the designated performer is not available.

The person who entered the order on behalf of another individual for example in the case of a verbal or a telephone order.

The reason or the indication for ordering or not ordering the medication.

This could be a diagnosis code. If a full condition record exists or additional detail is needed, use reasonReference.

Condition or observation that supports why the medication was ordered.

This is a reference to a condition or observation that is the reason for the medication order. If only a code exists, use reasonCode.

The URL pointing to a protocol, guideline, orderset, or other definition that is adhered to in whole or in part by this MedicationRequest.

The URL pointing to an externally maintained protocol, guideline, orderset or other definition that is adhered to in whole or in part by this MedicationRequest.

A plan or request that is fulfilled in whole or in part by this medication request.

A shared identifier common to all requests that were authorized more or less simultaneously by a single author, representing the identifier of the requisition or prescription.

Requests are linked either by a "basedOn" relationship (i.e. one request is fulfilling another) or by having a common requisition. Requests that are part of the same requisition are generally treated independently from the perspective of changing their state or maintaining them after initial creation.

The description of the overall patte3rn of the administration of the medication to the patient.

This attribute should not be confused with the protocol of the medication.

Insurance plans, coverage extensions, pre-authorizations and/or pre-determinations that may be required for delivering the requested service.

Extra information about the prescription that could not be conveyed by the other attributes.

Indicates how the medication is to be used by the patient.

There are examples where a medication request may include the option of an oral dose or an Intravenous or Intramuscular dose. For example, "Ondansetron 8mg orally or IV twice a day as needed for nausea" or "Compazine® (prochlorperazine) 5-10mg PO or 25mg PR bid prn nausea or vomiting". In these cases, two medication requests would be created that could be grouped together. The decision on which dose and route of administration to use is based on the patient's condition at the time the dose is needed.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Indicates the order in which the dosage instructions should be applied or interpreted.

If the sequence number of multiple Dosages is the same, then it is implied that the instructions are to be treated as concurrent. If the sequence number is different, then the Dosages are intended to be sequential.

Free text dosage instructions e.g. SIG.

Free text dosage instructions can be used for cases where the instructions are too complex to code. The content of this attribute does not include the name or description of the medication. When coded instructions are present, the free text instructions may still be present for display to humans taking or administering the medication. It is expected that the text instructions will always be populated. If the dosage.timing attribute is also populated, then the dosage.text should reflect the same information as the timing. Additional information about administration or preparation of the medication should be included as text.

Supplemental instructions to the patient on how to take the medication (e.g. "with meals" or"take half to one hour before food") or warnings for the patient about the medication (e.g. "may cause drowsiness" or "avoid exposure of skin to direct sunlight or sunlamps").

Additional instruction is intended to be coded, but where no code exists, the element could include text. For example, "Swallow with plenty of water" which might or might not be coded.

Information about administration or preparation of the medication (e.g. "infuse as rapidly as possibly via intraperitoneal port" or "immediately following drug x") should be populated in dosage.text.

Instructions in terms that are understood by the patient or consumer.

When medication should be administered.

The timing schedule for giving the medication to the patient. This data type allows many different expressions. For example: "Every 8 hours"; "Three times a day"; "1/2 an hour before breakfast for 10 days from 23-Dec 2011:"; "15 Oct 2013, 17 Oct 2013 and 1 Nov 2013". Sometimes, a rate can imply duration when expressed as total volume / duration (e.g. 500mL/2 hours implies a duration of 2 hours). However, when rate doesn't imply duration (e.g. 250mL/hour), then the timing.repeat.duration is needed to convey the infuse over time period.

This attribute might not always be populated while the Dosage.text is expected to be populated. If both are populated, then the Dosage.text should reflect the content of the Dosage.timing.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Identifies specific times when the event occurs.

In a Medication Administration Record, for instance, you need to take a general specification, and turn it into a precise specification.

A set of rules that describe when the event is scheduled.

Many timing schedules are determined by regular repetitions.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

Either a duration for the length of the timing schedule, a range of possible length, or outer bounds for start and/or end limits of the timing schedule.

• type @ $this

Either a duration for the length of the timing schedule, a range of possible length, or outer bounds for start and/or end limits of the timing schedule.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

A total count of the desired number of repetitions across the duration of the entire timing specification. If countMax is present, this element indicates the lower bound of the allowed range of count values.

Repetitions may be limited by end time or total occurrences.

If you have both bounds and count, then this should be understood as within the bounds period, until count times happens.

If present, indicates that the count is a range - so to perform the action between [count] and [countMax] times.

How long this thing happens for when it happens. If durationMax is present, this element indicates the lower bound of the allowed range of the duration.

Some activities are not instantaneous and need to be maintained for a period of time.

For some events the duration is part of the definition of the event (e.g. IV infusions, where the duration is implicit in the specified quantity and rate). For others, it's part of the timing specification (e.g. exercise).

If present, indicates that the duration is a range - so to perform the action between [duration] and [durationMax] time length.

Some activities are not instantaneous and need to be maintained for a period of time.

For some events the duration is part of the definition of the event (e.g. IV infusions, where the duration is implicit in the specified quantity and rate). For others, it's part of the timing specification (e.g. exercise).

The units of time for the duration, in UCUM units.

The number of times to repeat the action within the specified period. If frequencyMax is present, this element indicates the lower bound of the allowed range of the frequency.

If present, indicates that the frequency is a range - so to repeat between [frequency] and [frequencyMax] times within the period or period range.

Indicates the duration of time over which repetitions are to occur; e.g. to express "3 times per day", 3 would be the frequency and "1 day" would be the period. If periodMax is present, this element indicates the lower bound of the allowed range of the period length.

If present, indicates that the period is a range from [period] to [periodMax], allowing expressing concepts such as "do this once every 3-5 days.

The units of time for the period in UCUM units.

If one or more days of week is provided, then the action happens only on the specified day(s).

If no days are specified, the action is assumed to happen every day as otherwise specified. The elements frequency and period cannot be used as well as dayOfWeek.

Specified time of day for action to take place.

When time of day is specified, it is inferred that the action happens every day (as filtered by dayofWeek) on the specified times. The elements when, frequency and period cannot be used as well as timeOfDay.

An approximate time period during the day, potentially linked to an event of daily living that indicates when the action should occur.

Timings are frequently determined by occurrences such as waking, eating and sleep.

When more than one event is listed, the event is tied to the union of the specified events.

The number of minutes from the event. If the event code does not indicate whether the minutes is before or after the event, then the offset is assumed to be after the event.

A code for the timing schedule (or just text in code.text). Some codes such as BID are ubiquitous, but many institutions define their own additional codes. If a code is provided, the code is understood to be a complete statement of whatever is specified in the structured timing data, and either the code or the data may be used to interpret the Timing, with the exception that .repeat.bounds still applies over the code (and is not contained in the code).

BID etc. are defined as 'at institutionally specified times'. For example, an institution may choose that BID is "always at 7am and 6pm". If it is inappropriate for this choice to be made, the code BID should not be used. Instead, a distinct organization-specific code should be used in place of the HL7-defined BID code and/or a structured representation should be used (in this case, specifying the two event times).

Indicates whether the Medication is only taken when needed within a specific dosing schedule (Boolean option), or it indicates the precondition for taking the Medication (CodeableConcept).

Can express "as needed" without a reason by setting the Boolean = True. In this case the CodeableConcept is not populated. Or you can express "as needed" with a reason by including the CodeableConcept. In this case the Boolean is assumed to be True. If you set the Boolean to False, then the dose is given according to the schedule and is not "prn" or "as needed".

Body site to administer to.

A coded specification of the anatomic site where the medication first enters the body.

If the use case requires attributes from the BodySite resource (e.g. to identify and track separately) then use the standard extension bodySite. May be a summary code, or a reference to a very precise definition of the location, or both.

How drug should enter body.

A code specifying the route or physiological path of administration of a therapeutic agent into or onto a patient's body.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

A reference to a code defined by a terminology system.

Allows for alternative encodings within a code system, and translations to other code systems.

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

The identification of the code system that defines the meaning of the symbol in the code.

Need to be unambiguous about the source of the definition of the symbol.

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Need to refer to a particular code in the system.

A representation of the meaning of the code in the system, following the rules of the system.

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Very often the text is the same as a displayName of one of the codings.

Technique for administering medication.

A coded value indicating the method by which the medication is introduced into or onto the body. Most commonly used for injections. For examples, Slow Push; Deep IV.

Terminologies used often pre-coordinate this term with the route and or form of administration.

The amount of medication administered.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

The kind of dose or rate specified, for example, ordered or calculated.

If the type is not populated, assume to be "ordered".

The comparator is not used on a SimpleQuantity

The amount of therapeutic or other substance given at one administration event.

The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use may also restrict the values for the comparator.

• type @ $this

Amount of medication per dose.

The amount of therapeutic or other substance given at one administration event.

Note that this specifies the quantity of the specified medication, not the quantity for each active ingredient(s). Each ingredient amount can be communicated in the Medication resource. For example, if one wants to communicate that a tablet was 375 mg, where the dose was one tablet, you can use the Medication resource to document that the tablet was comprised of 375 mg of drug XYZ. Alternatively if the dose was 375 mg, then you may only need to use the Medication resource to indicate this was a tablet. If the example were an IV such as dopamine and you wanted to communicate that 400mg of dopamine was mixed in 500 ml of some IV solution, then this would all be communicated in the Medication resource. If the administration is not intended to be instantaneous (rate is present or timing has a duration), this can be specified to convey the total amount to be administered over the period of time as indicated by the schedule e.g. 500 ml in dose, with timing used to convey that this should be done over 4 hours.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

The value of the measured amount. The value includes an implicit precision in the presentation of the value.

Precision is handled implicitly in almost all cases of measurement.

The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

A human-readable form of the unit.

There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

The identification of the system that provides the coded form of the unit.

Need to know the system that defines the coded form of the unit.

A computer processable form of the unit in some unit representation system.

Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.

Amount of medication per unit of time.

Identifies the speed with which the medication was or will be introduced into the patient. Typically the rate for an infusion e.g. 100 ml per 1 hour or 100 ml/hr. May also be expressed as a rate per unit of time e.g. 500 ml per 2 hours. Other examples: 200 mcg/min or 200 mcg/1 minute; 1 liter/8 hours. Sometimes, a rate can imply duration when expressed as total volume / duration (e.g. 500mL/2 hours implies a duration of 2 hours). However, when rate doesn't imply duration (e.g. 250mL/hour), then the timing.repeat.duration is needed to convey the infuse over time period.

It is possible to supply both a rate and a doseQuantity to provide full details about how the medication is to be administered and supplied. If the rate is intended to change over time, depending on local rules/regulations, each change should be captured as a new version of the MedicationRequest with an updated rate, or captured with a new MedicationRequest with the new rate.

It is possible to specify a rate over time (for example, 100 ml/hour) using either the rateRatio and rateQuantity. The rateQuantity approach requires systems to have the capability to parse UCUM grammer where ml/hour is included rather than a specific ratio where the time is specified as the denominator. Where a rate such as 500ml over 2 hours is specified, the use of rateRatio may be more semantically correct than specifying using a rateQuantity of 250 mg/hour.

Upper limit on medication per unit of time.

The maximum total quantity of a therapeutic substance that may be administered to a subject over the period of time. For example, 1000mg in 24 hours.

This is intended for use as an adjunct to the dosage when there is an upper cap. For example "2 tablets every 4 hours to a maximum of 8/day".

Upper limit on medication per administration.

The maximum total quantity of a therapeutic substance that may be administered to a subject per administration.

This is intended for use as an adjunct to the dosage when there is an upper cap. For example, a body surface area related dose with a maximum amount, such as 1.5 mg/m2 (maximum 2 mg) IV over 5 – 10 minutes would have doseQuantity of 1.5 mg/m2 and maxDosePerAdministration of 2 mg.

Upper limit on medication per lifetime of the patient.

The maximum total quantity of a therapeutic substance that may be administered per lifetime of the subject.

Indicates the specific details for the dispense or medication supply part of a medication request (also known as a Medication Prescription or Medication Order). Note that this information is not always sent with the order. There may be in some settings (e.g. hospitals) institutional or system support for completing the dispense details in the pharmacy department.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Indicates the quantity or duration for the first dispense of the medication.

If populating this element, either the quantity or the duration must be included.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

The amount or quantity to provide as part of the first dispense.

The length of time that the first dispense is expected to last.

The minimum period of time that must occur between dispenses of the medication.

This indicates the validity period of a prescription (stale dating the Prescription).

Indicates when the Prescription becomes valid, and when it ceases to be a dispensable Prescription.

It reflects the prescribers' perspective for the validity of the prescription. Dispenses must not be made against the prescription outside of this period. The lower-bound of the Dispensing Window signifies the earliest date that the prescription can be filled for the first time. If an upper-bound is not specified then the Prescription is open-ended or will default to a stale-date based on regulations.

An integer indicating the number of times, in addition to the original dispense, (aka refills or repeats) that the patient can receive the prescribed medication. Usage Notes: This integer does not include the original order dispense. This means that if an order indicates dispense 30 tablets plus "3 repeats", then the order can be dispensed a total of 4 times and the patient can receive a total of 120 tablets. A prescriber may explicitly say that zero refills are permitted after the initial dispense.

If displaying "number of authorized fills", add 1 to this number.

The amount that is to be dispensed for one fill.

Identifies the period time over which the supplied product is expected to be used, or the length of time the dispense is expected to last.

In some situations, this attribute may be used instead of quantity to identify the amount supplied by how long it is expected to last, rather than the physical quantity issued, e.g. 90 days supply of medication (based on an ordered dosage). When possible, it is always better to specify quantity, as this tends to be more precise. expectedSupplyDuration will always be an estimate that can be influenced by external factors.

Indicates the intended dispensing Organization specified by the prescriber.

Indicates whether or not substitution can or should be part of the dispense. In some cases, substitution must happen, in other cases substitution must not happen. This block explains the prescriber's intent. If nothing is specified substitution may be done.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

True if the prescriber allows a different drug to be dispensed from what was prescribed.

This element is labeled as a modifier because whether substitution is allow or not, it cannot be ignored.

Indicates the reason for the substitution, or why substitution must or must not be performed.

A link to a resource representing an earlier order related order or prescription.

Indicates an actual or potential clinical issue with or between one or more active or proposed clinical actions for a patient; e.g. Drug-drug interaction, duplicate therapy, dosage alert etc.

This element can include a detected issue that has been identified either by a decision support system or by a clinician and may include information on the steps that were taken to address the issue.

Links to Provenance records for past versions of this resource or fulfilling request or event resources that identify key state transitions or updates that are likely to be relevant to a user looking at the current version of the resource.

This might not include provenances for all versions of the request – only those deemed “relevant” or important. This SHALL NOT include the provenance associated with this current version of the resource. (If that provenance is deemed to be a “relevant” change, it will need to be added as part of a later update. Until then, it can be queried directly as the provenance that points to this version using _revinclude All Provenances should have some historical version of this Request as their subject.).