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HelpTest ID: TB2LN Susceptibility, Mycobacterium tuberculosis Complex, Second Line, Varies
Infectious
Useful For
Determination of Mycobacterium tuberculosis complex minimal inhibitory concentrations to second-line antimicrobial agents
Additional Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| STV2 | Susceptibility, Mtb Cx, 2nd Line | No, (Bill Only) | Yes |
Testing Algorithm
When this test is ordered, the additional test will always be performed at an additional charge.
Special Instructions
Reporting Name
Susceptibility, Mtb Complex, 2 LineSpecimen Type
VariesAdditional Testing Requirements
CTB / Mycobacteria and Nocardia Culture, Varies or CTBID / Culture Referred for Identification, Mycobacterium and Nocardia, Varies must also be ordered and will be charged separately unless identification of organism is provided.
Shipping Instructions
1. For shipping information see Infectious Specimen Shipping Guidelines.
2. Place specimen in a large infectious container and label as an etiologic agent/infectious substance.
Necessary Information
Specimen source and suspected organism identification are required.
Specimen Required
Specimen Type: Organism
Supplies: Infectious Container, Large (T146)
Container/Tube: Middlebrook 7H10 agar slant
Specimen Volume: Isolate
Collection Instructions: Organism must be in pure culture, actively growing.
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Refrigerated | |||
Clinical Information
The Clinical and Laboratory Standards Institute (CLSI) provides a consensus protocol for the methods, antimycobacterial agents, and critical concentrations of each agent to be tested in order to permit standardized interpretation of Mycobacterium tuberculosis complex susceptibility testing results. CLSI guidelines suggest that second-line agents should be tested when an isolate of M tuberculosis complex is resistant to rifampin, is monoresistant to the critical concentration of isoniazid and the physician intends to use a fluoroquinolone for therapy, or is resistant to any combination of 2 first-line agents.
This test uses a broth microdilution method for susceptibility testing of M tuberculosis complex against second-line agents. Agents tested are amikacin, ethionamide, kanamycin, moxifloxacin, ofloxacin, p-aminosalicylic acid, rifabutin, and streptomycin. In contrast to other M tuberculosis complex susceptibility methods which test 1 or 2 critical concentrations of a drug, this method examines a range of drug concentrations and produces a minimal inhibitory concentration result.
Reference Values
Interpretive criteria and reporting guidelines are followed using the Clinical Laboratory Standards Institute (CLSI) M24S document.
Interpretation
Results are reported as minimal inhibitory concentrations in mcg/mL.
This test is used as an alternative to TB1LN / Antimicrobial Susceptibility, Mycobacterium tuberculosis Complex, First Line, Varies when reagents are not available to perform the TB1LN test. Ethambutol, isoniazid, and rifampin agents are not routinely reported with this test.
Clinical Reference
1. Hall L, Jude KP, Clark SL, et al. Evaluation of the Sensititre MycoTB plate for susceptibility testing of the Mycobacterium tuberculosis complex against first- and second-line agents. J Clin Microbiol. 2012;50:3732-3734
2. Centers for Disease Control and Prevention. Treatment of Tuberculosis, American Thoracic Society, CDC, and Infectious Diseases Society of America. MMWR 2003;52(No. RR-11):1-79
3. Woods GL, Lin S-Y G, Desmond EP. Susceptibility test methods: Mycobacteria, Nocardia and other Actinomycetes. In: Versalovic J, Carroll KC, Funke G, et al. Manual of Clinical Microbiology. 10th ed. ASM Press; 2011: 1215-1238
4. CLSI. Performance Standards for Susceptibility Testing of Mycobacteria, Nocardia species, and Other Aerobic Actinomycetes. First edition CLSI supplement M62. Clinical and Laboratory Standards Institute; 2018
Day(s) Performed
Monday through Sunday
Report Available
21 to 30 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
87186-Susceptibility, Mtb Cx, 2nd Line
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TB2LN | Susceptibility, Mtb Complex, 2 Line | 29579-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TB2LN | Susceptibility, Mtb Complex, 2 Line | 29579-0 |
Method Name
Minimum Inhibitory Concentration (MIC) by Microtiter Broth Dilution Method
Specimen Minimum Volume
See Specimen Required
mml-mycobacteria