If I'm reading the documentation correctly there is no difference at the PKB end between this and A31 (Update Patient Record) from the PKB perspective. If there is an existing record it will be updated and if not one will be created. The update seems to involve the replacement of any existing data so would require the full record to be sent each time.

Message Specification

Segment	Field	Component	Notes	UKRDC DB Location
MSH			See MSH Page
PID			See PID Page
AL1			Allergy	N/A
DG1
	DG1-3		Diagnosis
		DG1-3.1	Diagnosis Code	diagnosis.diagnosiscode
		DG1-3.2	Diagnosis Text	diagnosis.diagnosisdesc
		DG1-3.3	Diagnosis Coding Standard	diagnosis.diagnosiscodestd
		DG1-3.4	Diagnosis Alternate Code	N/A
		DG1-3.5	Diagnosis Alternate Text	N/A
		DG1-3.6	Diagnosis Alternate Coding Standard	N/A
	DG1-5		Diagnosis Timestamp
		DG1-5.1	Diagnosis Timestamp	diagnosis.identificationtime
	DG1-6		Diagnosing Clinician	N/A
ZRX			Medication
	ZRX-1		Quantity / Timing
		ZRX-1.2	Repeat Pattern	medication.frequency
		ZRX-1.4	Start Timestamp	medication.fromtime
		ZRX-1.5	End Timestamp	medication.totime
	ZRX-2		Product
		ZRX-2.1	Medication code	???
		ZRX-2.2	Medication Text	medication.drugproductgeneric
		ZRX-2.3	Medication Coding System	???
		ZRX-2.4	Medication Alternate Code	N/A
		ZRX-2.5	Medication Alternate Text	N/A
		ZRX-2.6	Medication Alternate Coding System	N/A
	ZRX-3		Dose Quantity
		ZRX-3.1	Dose Quantity	medication.dosequantity
	ZRX-5		Units
		ZRX-5.1	Unit Code	medication.dosequantitycode
		ZRX-5.2	Unit Text	medication.dosequantitydesc
		ZRX-5.3	Unit Coding System	medication.dosequantitycodestd
		ZRX-5.4	Unit Alterate Code	N/A
		ZRX-5.5	Unit Alternate Text	N/A
		ZRX-5.6	Unit Alternate Coding System	N/A
	ZRX-7		Instructions	N/A
	ZRX-13		Source Information	N/A

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