I’d first like to caution you on making plans for using LOINC other than what it’s intended for. Some people have tried to use LOINC as the principal identifier in their LIS or LIMS, only to find out the multiple use cases of a business operation called for similar tests (with different pricing or performance characteristics) that couldn’t keep the same LOINC, because the LIS field needed to be unique. It might be helpful to get some mapping/identification done on your current catalog, and start observing your own use cases.
If you enter XDR in search.loinc.org you’ll see 6 LOINCs for Bedaquiline or it’s metabolite. Notice the method of Slow Growing Mycobacteria for 88704-2. Would that be a fit? I find the ease of putting in just one keyword in the search window to get started, or a portion of one keyword will start you faster.
That method didn’t work for HAIN as a keyword however. A quick google scholar search found https://pubmed.ncbi.nlm.nih.gov/25632618/ with HAIN https://www.hain-lifescience.de/en/products/microbiology/mycobacteria/tuberculosis/genotype-mtbdrplus.html . It appears this test looks for rifampin (rpoB gene) and isoniazide (katG and inhA) resistance “The identification of rifampicin resistance is enabled by the detection of the most significant mutations of the rpoB gene (coding for the β-subunit of the RNA polymerase). For testing the high level isoniazid resistance, the katG gene (coding for the catalase peroxidase) is examined and for testing the low level isoniazid resistance, the promoter region of the inhA gene (coding for the NADH enoyl ACP reductase) is analyzed.”
If you’ll search.loinc.org for “drug resistant”, you’ll see the single gene result fields; these would be used presuming each gene was reported separately. Clicking on any other of these will take you to the detail page, where you can find the order LOINC of 94053-6 Mycobacterium tuberculosis complex resistance panel by Molecular genetics method. There are no Required/Optional/Conditional’s listed on this panel, so it could be used for the ordering side.
Be sure to look through the Microbiology Mapping Guide, the Knowledge Base, and past webinars/conference recordings at www.loinc.org. I know a while ago a presentation contained tips and tricks for microbiology.