What qualifies as ABXBACT?

While working on a Lab hierarchy content, we’ve noticed that the class “ABXBACT” refers so several different type of codes which doesn’t seem to belong together:

73657-9Varicella zoster virus ORF36 genotype [Identifier]

77734-2Mycobacterium abscessus complex clarithromycin resistance erm(41) full length gene [Presence] by Molecular method

96107-8Bedaquiline [Susceptibility] by Genotype method

If all of them really do belong in the same class, how come only one has “[Susceptibility]” in it’s long common name?
I couldn’t find an answer in the documentation.

Hello Noam,

Apologies for the delay in responding. The ABXBACT class refers to a microorganism’s ability to defend itself from a medication administered to an infected patient. The original SUSC property at LOINC origin didn’t have genetic material of microorganisms to determine their ability to “fight against” a medication.

Since that time, molecular microbiology has come into vogue as a new technology. Now the laboratory is able to determine from the organism’s nucleic acid material what genetic structure is present that allows it to be resistant to (or susceptible to) a particular class of antibiotics/antivirals.

Take 73657-9 Varicella zoster virus ORF36 genotype as an example. The detail description states " Genotypic detection of Varicella zoster virus resistance to antivirals is based on ORF36 (thymidine kinase, TK) and ORF28 (DNA polymerase, Pol) gene sequencing."

Example answers (scrolling down on the same page) provide 5 potential mutations or variants that provide resistance to medication: D18N, G24E, D129N, etc. Notice the property and scale are PRID and NOM; that’s different from the SUSC ORD/QN property normally seen in susceptibility resistance. If any of those 5 mutations are found, there’s probably an interpretive comment about the virus’s ability to be resistant.

As a second example, 96107-8 Bedaquiline [Susceptibility] by Genotype method has a SUSC property, and example answers of Susceptible and Resistant. The laboratory is doing an interpretation based on their genotyping of the Mycobacterium organism isolated from the patient, but their example answers are not reporting the specific mutation or variant that was found.

The LOINC database is intended to report laboratory information in a wide variety of methods; we can always find something to wonder about. With the size and breadth of the database, it helps to focus on your site’s use case. Are you trying to map a facility? Are you doing research on microbiology resistance to medications? Please reply if you need more specific information.

All the best,