Supplying LOINC Codes

PKB encourages any customer that is sending in Pathology results to consider including the appropriate LOINC or SNOMED code for a test result instead of the local test identifier that is generally held. This is because the Test results from two different sources will never share the same [[Local Test Type]] since these are scoped to the source organisation. By default, this means they have different test types and as such will not appear on the same graph. In order to appear on the same graph the [[Local Test Type]] entries must be mapped to the same supported LOINC test type. This is a process known as LOINC mapping, and is undertaken by the sending organisation to ensure that PKB is sent the required LOINC information in the integration feed.

There is a page in the PKB Deployment Wiki that explains in detail the benefit of providing LOINC codes:
https://wiki.patientsknowbest.com/space/DEPLOY/3543662596/Benefits+of+LOINC+Mapping, but for ease of understanding, the key benefits are:

• A direct link for users from the PKB UI to Lab Tests Online information for that specific result is automatically provided

• Results sent from different organisations or entered manually via the UI can be mapped on the same graph

• It avoids the “same” results from an organisation being mapped separately due to a difference in either the code, sending system or units used.

• LOINC mapped results can be added to Care Plans created in PKB

• LOINC mapped results have a consistency in the result name displayed to users, as opposed to relying on the name provided in the HL7 feed.

• Results will automatically be added to the correct report panels in the PKB UI.

• Results from different sources can be extracted with a standardised code set and used for research purposes.

How do Organisations implement this?

PKB can only process the data we are provided, so we are reliant on organisations sending us an agreed upon LOINC code and unit of measurement for the pathology results in their feed to us.

This “mapping” process can take a little time and will need the support of a Pathology expert from the sending organisation, who will need to review the tests supported by PKB and advise which entry the local test code and unit measurement combinations map to. Should PKB need to provide support/guidance and/or extend the range of results we support, then this can be accommodated.

The integration team of the sending organisation will usually create a local lookup table that can checked when results “arrive” from the Pathology system. Checking that table for a match on local test id and unit and replacing them in the HL7 message to PKB with the assigned LOINC code and measurement unit string.

Are SNOMED codes supported in the same way?

PKB are working on mapping our LOINC coded data to the correct SNOMED code, so that in the future we can provide the same level of enhanced functionality upon receipt of a SNOMED code. Whilst this is not currently available, we would encourage organisations to provide SNOMED coded data if they have it, as when PKB completes our internal mapping work they will automatically benefit.

What are the technical considerations?

1. LOINC has to be specified as the result test coding system in OBX-3.3 of the ORU message

   1. The code system matches (case-insensitively) the string "LOINC"

2. The code value and unit value both match (case-sensitively) one one of the LOINC test types supported by PKB. Ensuring the unit information in (OBX-6 of the ORU message) sent with LOINC-mapped results is correct

3. if you tell us the units you are using for each test, we’ll make sure we can support those units for that test. We match on LOINC code and unit, but do need to map each possibility.

   1. Units need to match our expectation exactly

   2. If a LOINC has multiple unit possibilities, we need to map each one. Each combination is graphed separately in PKB

   3. Our matching is done on string matching, so units must match exactly (including CAPS use)