HL7 Admission Updates v2.4

Question

This is a really simple question but no amount of Googling has found me an answer. I appreciate everyone has their own interpretation of HL7 but I'd appreciate some guidance on the following question:

When a hospital system admits a patient it will create an A01 message.

If a user of the hospital system then amends the admission detail e.g. changes the time of admission how is this conveyed in HL7? Is it through the send of a full A01 with the assumption that receiving systems will just pick up the unique key fields and realise it's already received it and hence process it as a change.

Or is it an A08? If it is an A08 I assume the same would apply for discharges (A03) and transfers (A02) and in which case how can the receiving system differentiate between an A08 for a transfer and an A08 for an admission? - I can't see any field in an A08 that describes the message type down to this detail.

Answer 1

The answer varies entirely from application to application. Though I cannot define a new trigger event, I can simply change the use case.

If I were to exchange information, I will ask the other system to configure their side, to accept what my application is capable of delivering. Modern interface engine, which come embedded in the product itself, have check boxes around to define what need to be interpreted as patient admit, update etc.

Because My application is build on few specifications, and most of the time the recieving application collects this data and configures their side. It could be an EMR or a PMS at the other hand, but this handshake agreement is required before you can setup your interface.

If during the handshake I see that I cannot digest what you are going to send to me, than I unfortunately have to call it off or see new workaround or log a Dev ticket to get it done.

Most of the application follow specific pattern, with only minor changes in one or two events. Now, Let's say I define my system and call A04 as register a patient and A08 and update a patient. HL7 job is to specify or just carry A08 and A04 in the respective fields. However, on the other side the application need to interpret as required.

So What exactly happens at the message level- Nothing different.

Earlier in the A04 it was carrying JHON DOE as patient name. Later on in the subsequent A08 it carried JOHN DOE patients Demographics, with the same MRN in PID.2. That's it.

Discharges and Transfers A02 and A03 appear on INpatients only, but I have not ever seen them being used (cos I have always worked on Outpatients). I can use for transfers, A02,A06,A07,A25,A26 and A27 and likewise.

Is HL7 an exact science? - NO. What defined are possible events that occur in Healthcare system, the interpretation however, can change on a case to case basis. Its job is to convey certain information in certain fields as defined. You can't really send SSN in Patient ID field. Cos that is illogical and an abuse to HL7.

I hope that helps. :)

Answer 2

HL7 v2.x has messages to amend patient data, visit data and account data. You can download the specs for free from hl7.org, just create an account and search for HL7 2.4. On chapter 03 Patient Administration you will find the events ANN for the ADT message. For example, ADT A42 Merge Visit - Visit Number allows to correct visit data. A08 should be used to update info, but only if there is no other more specific message to update that info, from the specs:

Blockquote This trigger event is used when any patient information has changed but when no other trigger event has occurred. For example, an A08 event can be used to notify the receiving systems of a change of address or a name change. We strongly recommend that the A08 transaction be used to update fields that are not updated by any of the other trigger events. If there are specific trigger events for this update, these trigger events should be used. For example, if a patient's address and location are to be changed, then an A08 is used to change the patient address and the appropriate patient location trigger event is used to change the patient location. The A08 event can include information specific to an episode of care, but it can also be used for demographic information only.

Hope that helps.