May I raise a discussion on the mapping of Choriogonadotropin.beta subunit [Units/volume] in Serum or Plasma. Currently there are laboratories applying the WHO international standard for the test. And in LOINC, there is a related concept:
20415-6 Choriogonadotropin.beta subunit [Units/volume] in Serum or Plasma by Immunoassay (EIA) 3rd IS
Since the WHO had released the latest 5th standard and local laboratories adopted this standard, is it appropriate to propose a new, up-to-date concept, specifying the method as 5th IS?
We suggest the use of test codes without IS in their name and encourage labs to report that information either as text in the method field of the HL7 message or in a comment when they think it is important.
We have found that laboratories are often inconsistent about the use of the various IS standard in their test names. Additionally, one reason for changing of IS standards is that the control specimens for the existing standard run out. This does not always mean a real difference in the new IS standard compared to the old. Further, the tests for pituitary hormones vary greatly in their test results because of the differences in the fragment and sections of the polypeptides they pick up. So on the one hand, it has been difficult to know what IS standard a given lab is really using when they make a submission to LOINC. On the other hand, differences in test methods create intrinsic noise in these tests.
So with advice from our laboratory chemistry experts, Regenstrief has decided not to try and keep up with the IS distinctions and should probably discourage the use of the terms with IS in their name.
We welcome input on these decisions.
Jami Deckard, MS
LOINC Content Developer
Regenstrief Institute, Inc.