# What qualifies as ABXBACT?

**URL:** <https://forum.loinc.org/t/what-qualifies-as-abxbact/1169>\
**Category:** antibiotic-susceptibilities\
**Created:** [November 23, 2022, 4:40am UTC](https://forum.loinc.org/t/what-qualifies-as-abxbact/1169 "2022-11-23T04:40:40Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![noamyo](https://forum.loinc.org/letter_avatar_proxy/v4/letter/n/3da27b/32.png) [@noamyo](https://forum.loinc.org/u/noamyo)\
**Post date:** [November 23, 2022, 4:40am UTC](https://forum.loinc.org/t/what-qualifies-as-abxbact/1169/1 "2022-11-23T04:40:40Z")

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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.

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**Author:** ![pdbanning](https://forum.loinc.org/letter_avatar_proxy/v4/letter/p/9f8e36/32.png) [@pdbanning](https://forum.loinc.org/u/pdbanning)\
**Post date:** [December 4, 2022, 10:55pm UTC](https://forum.loinc.org/t/what-qualifies-as-abxbact/1169/2 "2022-12-04T22:55:41Z")

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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,

Pam

&nbsp;

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**Author:** ![system](https://forum.loinc.org/uploads/default/original/1X/dbab97ce9b2987d788a376e254fcaae249f3b672.png) [@system](https://forum.loinc.org/u/system)\
**Post date:** [June 23, 2023, 3:36pm UTC](https://forum.loinc.org/t/what-qualifies-as-abxbact/1169/3 "2023-06-23T15:36:51Z")

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