A record of a request for a diagnostic investigation service to be performed.

Who or what the investigation is to be performed on. This is usually a human patient, but diagnostic tests can also be requested on animals, groups of humans or animals, devices such as dialysis machines, or even locations (typically for environmental scans).

The practitioner that holds legal responsibility for ordering the investigation.

Identifiers assigned to this order instance by the orderer and/or the receiver and/or order fulfiller.

The identifier.type element is used to distinguish between the identifiers assigned by the orderer (known as the 'Placer' in HL7 v2 ) and the producer of the observations in response to the order ( known the 'Filler' in HL7 v2) . For further discussion and examples see the notes section below.

An encounter that provides additional information about the healthcare context in which this request is made.

An explanation or justification for why this diagnostic investigation is being requested. This is often for billing purposes. May relate to the resources referred to in supportingInformation.

This may be used to decide how the diagnostic investigation will be performed, or even if it will be performed at all. Use CodeableConcept text element if the data is free (uncoded) text as shown in the CT Scan example.

Additional clinical information about the patient or specimen that may influence test interpretations. This includes observations explicitly requested by the producer(filler) to provide context or supporting information needed to complete the order.

This information includes diagnosis, clinical findings and other observations. In laboratory ordering these are typically referred to as "ask at order entry questions (AOEs)". Examples include reporting the amount of inspired oxygen for blood gasses, the point in the menstrual cycle for cervical pap tests, and other conditions that influence test interpretations.

One or more specimens that the diagnostic investigation is about.

Many investigation requests will create a need for specimens, but the request itself is not actually about the specimens. This is provided for when the diagnostic investigation is requested on already existing specimens.

The status of the order.

Typically the system placing the order sets the status to requested. Thereafter, the order is maintained by the receiver that updates the status as the request is handled.

The clinical priority associated with this order.

The Order resource also has a priority. Generally, these should be the same, but they can be different, for instance in the case where the clinician indicates that the order is urgent, but the subsequent workflow process overrule this priority for some reason. The effective default value is "normal".

A summary of the events of interest that have occurred as the request is processed. E.g. when the order was made, various processing steps (specimens received), when it was completed.

This is not the same as an audit trail - it is a view of the important things that happened in the past. Typically, there would only be one entry for any given status, and systems may not record all the status events.

The status for the event.

Additional information about the event that occurred - e.g. if the status remained unchanged.

The date/time at which the event occurred.

The person who was responsible for performing or recording the action.

The specific diagnostic investigations that are requested as part of this request. Sometimes, there can only be one item per request, but in most contexts, more than one investigation can be requested.

There would always be at least one item in normal usage, but this is optional so that a workflow can quote order details without having to list the items.

A code that identifies a particular diagnostic investigation, or panel of investigations, that have been requested.

Many laboratory tests and radiology tests embed the specimen/organ system in the test name, for example, serum or serum/plasma glucose, or a chest xray. The specimen may not be recorded separately from the test code.

If the item is related to a specific specimen.

A single specimen should not appear in both DiagnosticOrder.specimen and DiagnosticOrder.item.specimen.

Anatomical location where the request test should be performed. This is the target site.

If the use case requires BodySite to be be handled as a separate resource instead of an inline coded element ( e.g. to identify and track separately) then use the standard extension body-site-instance.

The status of this individual item within the order.

If the request has multiple items that have their own life cycles, then the items will have their own status while the overall diagnostic order is (usually) "in-progress".

A summary of the events of interest that have occurred as this item of the request is processed.

Any other notes associated with this patient or specimen or order (e.g. "patient hates needles").