CDISC Therapeutic Areas and LOINC

In a recent discussion with an important CDISC representative (well, they are all important), I heard the remark that the therapeutic area user guides (TAUGs) may be the perfect forum to introduce people to LOINC coding for lab tests. So I downloaded them all, and searched them for:

• whether LOINC is mentioned at all
• whether there are lab tests described which are / maybe important for the specific therapeutic area
• whether the important lab tests that are described come with their LOINC code
• whether example of LB domain tables have the LOINC code (in LBLOINC) included

So, let's go!

TAUG multiple sclerosis

•  mentioned that --LOINC variable is not to be used in domains NV and OE
• no lab tests described

TAUG virology

• LOINC mentioned many times as standard reference technology for tests in the domains VR, PR.
• Shows up in many of the example tables, for example PFTSTRCD=48005-3, PFTSTRNM=LOINC
• No specific laboratory tests described

TAUG Influenza

•  LOINC not mentioned at all
• A few lab tests are described (e.g. nucleic acid amplification techniques - NAAT) for which LOINC coding exists (e.g. 68987-7, 38270-5), but the LOINC codes are not provided

TAUG Cardiovascular Studies

•  LBLOINC field and values provided in all LB example tables
• Not further explained what LOINC is, supposed to be known by the users

TAUG Asthma

• LOINC not mentioned at all
•  Different lab tests extensively described (e.g. Leukotriene E4, Immunoglobulin E) but no LOINC codes provided, though they exist (e.g. 33344-3, 62621-8, ...)

TAUG Alzheimer (2.0)

•  Mentioned as standard technology for genomic tests (PFTCVNM, PFTTESTCV)
• No specific laboratory tests described

TAUG Diabetes

•  LOINC not mentioned at all
• A good amount of proposed lab tests is defined in detail, but no LOINC codes are given, although they exist for each of the described test

So, the use of LOINC seem to be very different: in some cases, LOINC is used all the way (even expected to be known by the user - cardiovascular), and in other cases, the authors of the TAUG seem even not to be aware of LOINC as a coding system for the exact identification of lab tests.

In the case of the TAUG diabetes, I added the LOINC codes myself to one of the tables describing a set of lab tests. It took me less than 10 minutes to do so (thanks WWW!). Here is the result:

Personally, I strongly believe that providing/suggesting LOINC codes for lab tests in a TAUG is a very good thing, as it can be copied into the protocol, so that the protocol writers / investigators / SDTM generators do not need to interprete / guess which test exactly must be done or was done.