We recently received this request: https://loinc.org/95971-8/ --- SARS CoV-2 stimulated gamma interferon [Presence] in Blood. We also recieved requests for the following LOINC codes: 95974-2, 95972-6, and 95973-4. Upon further research on all 4 LOINC codes, they are referring to the IFNg Response Assay, which has been modeled in the LB domain in the TB-TAUG.
The IFNG Response test toward M. Tuberculosis is modeled in the LB domain, in the TB-TAUG as the following:
ELISA:
ELISPOT:
There are several issues with this modeling:
- Where do you show that this challenge assay is done against M. Tuberculosis (or any microbe of interest, like SARS-CoV-2)? - NHOID is not appropriate here because in this case because the subject of study is not the M. Tuberculosis itself but whether someone has been previously exposed to M. Tuberculosis. A positive result does not mean the person is currently infected with TB, it may mean that the person had been previously infected by, or vaccinated against M. Tuberculosis. NHOID is used when you know the bug or a reference strain is present in the testing sample.
- CP domain has developed a new standard variable called Test Condition Agent/CNDAGT (CP Specification), which is used to represent stimulating agents, like the values in ASSYAG above, should this variable be added to LB, or IS? TEAM AGREES
- Lastly, Interferon-Gamma Response Assay is a classic immunological test, is it correct to map this to the LB domain?
- Can we model this in the IS domain, see example dataset below. Yes - TEAM AGREES
- If we model this test in IS, how do we distinguish it from the INFg test in lab. Can we draw the line where if we are running a routine lab test looking for IFNg levels it goes to LB vs. IFNg challenge/response test toward a specific, known microorganism then it goes to IS? Yes-TEAM AGREES
If we were to model this in IS:
Similarly if we were to model Jozef's request in IS for https://loinc.org/95971-8/ --- SARS CoV-2 stimulated gamma interferon [Presence] in Blood