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Susceptibility testing of Mycobacterium tuberculosis complex isolates growing in pure culture.
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
TB2LN | Susceptibility, Mtb Complex, 2 Line | Yes | No |
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
STV1 | Susceptibility, Mtb Complex, Broth | No, (Bill Only) | Yes |
STV2 | Susceptibility, Mtb Cx, 2nd Line | No, (Bill Only) | Yes |
When this test is ordered, the additional test will always be performed and charged separately.
If resistance to a first line antimicrobial agent is detected, reflex testing of second line agents will be performed and charged.
Broth Dilution at Critical Drug Concentrations
Acid-Fast Bacilli (AFB)
AFB (Acid-Fast Bacilli)
Antibiotic Susceptibility
Antimicrobial Susceptibility, Mycobacterium tuberculosis
Bacillus, Acid-Fast
MTB (Mycobacterium tuberculosis)
Mycobacteria Antimicrobial Susceptibility (MIC) (Minimum Inhibitory Concentration)
Mycobacterium tuberculosis (MTB)
Susceptibility Testing
Susceptibility, Mycobacterium tuberculosis
TB (Tuberculosis)
Tubercle Bacilli: Mycobacterium tuberculosis
Tuberculosis (TB)
When this test is ordered, the additional test will always be performed and charged separately.
If resistance to a first line antimicrobial agent is detected, reflex testing of second line agents will be performed and charged.
Varies
If testing for the first-line agent pyrazinamide is desired, order TBPZA / Susceptibility, Mycobacterium tuberculosis Complex, Pyrazinamide, Varies.
If organism identification is not provided, 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.
1. See Infectious Specimen Shipping Guidelines in Special Instructions.
2. Place specimen in a large infectious container (T146) and label as an etiologic agent/infectious substance.
Specimen source and suspected organism identification are required.
Question ID | Description | Answers |
---|---|---|
Q00M0072 | Specimen source (Required) and Organism Identification (Required unless concurrent identification test is ordered) |
Specimen Type: Organism
Supplies: Infectious Container, Large (T146)
Container/Tube: Middlebrook 7H10 agar slant
Specimen Volume: Isolate
Collection Instructions:
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Agar plate | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | ||
Refrigerated |
Susceptibility testing of Mycobacterium tuberculosis complex isolates growing in pure culture.
When this test is ordered, the additional test will always be performed and charged separately.
If resistance to a first line antimicrobial agent is detected, reflex testing of second line agents will be performed and charged.
Initial treatment regimens for Mycobacterium tuberculosis complex often include isoniazid, rifampin, ethambutol, and pyrazinamide. Susceptibility testing of M tuberculosis complex isolates against these antimycobacterial agents is a key component of patient management.
The Clinical Laboratory Standards Institute (CLSI) provides consensus protocols for the methods, antimycobacterial agents, and critical concentrations of each agent to be tested to permit standardized interpretation of M tuberculosis complex susceptibility test results.
This test uses an US Food and Drug Administration cleared commercial system for rapid broth susceptibility testing of M tuberculosis complex and assesses resistance to antimycobacterial drugs at the CLSI-recommended critical concentrations.
Results are reported as susceptible or resistant.
Mycobacterium tuberculosis complex isolates are reported as susceptible or resistant to the aforementioned drugs at the critical concentrations.
Some experts believe that patients infected with strains exhibiting resistance to low levels of isoniazid but not exhibiting resistance to high levels may benefit from continuing therapy with this agent. A specialist in the treatment of tuberculosis should be consulted concerning the appropriate therapeutic regimen and dosages.
Isolates not received in pure culture may have delayed results because isolation is required prior to testing.
1. Nahid P, Mase SR, Migliori GB, et al. Treatment of Drug-Resistant Tuberculosis. An Official ATS/CDC/ERS/IDSA Clinical Practice Guideline [published correction appears in Am J Respir Crit Care Med. 2020 Feb 15;201(4):500-501
2. Clinical and Laboratory Standards Institute (CLSI). Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes. 3rd ed. CLSI standard M24. CLSI; 2018
3. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Susceptibility Testing of Mycobacteria, Nocardia spp., and Other Aerobic Actinomycetes. 2nd ed. CLSI supplement M24S. CLSI; 2023
This test method is based on growth or absence of growth of Mycobacterium tuberculosis complex isolates in broth cultures containing critical concentrations of the antimycobacterial agents isoniazid, rifampin, and ethambutol. One of two FDA-cleared platforms, the BACTEC MGIT 960 (Becton Dickinson) or the VersaTREK (ThermoFisher) will be used. (Brown-Elliott, BA, Cirillo DM, Musser KA, Rowlinson M-C. Susceptibility Test Methods: Mycobacteria, Nocardia, and Other Actinomycetes. In: Carroll KC, Pfaller MA, eds. Manual of Clinical Microbiology, 13th Edition. ASM Press, 2023)
The BACTEC MGIT 960 platform measures fluorescence in a Mycobacterial Growth Indicator Tube (MGIT) containing an M tuberculosis complex isolate in the presence of critical concentrations of an antimycobacterial agent. Antimycobacterial agents tested are isoniazid, rifampin, and ethambutol. (Package insert: BACTEC MGIT 960 SIRE Kit, BD Diagnostics, 2016)
The VersaTrek platform measures pressure changes inside bottles containing M tuberculosis complex isolates in the presence of critical concentrations of an antimycobacterial agent. Antimycobacterial agents tested are isoniazid, rifampin, and ethambutol. (Package insert: VersaTREK Mycobacteria Detection and Susceptibility Testing system, TREK Diagnostics, 04/2014)
Monday through Sunday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
87188 x 3-Antimicrobial Susceptibility, Mycobacterium tuberculosis Complex, Broth Method
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
TB1LN | Susceptibility, Mtb Complex, 1 Line | 29579-0 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
TB1LN | Susceptibility, Mtb Complex, 1 Line | 29579-0 |
Change Type | Effective Date |
---|---|
Test Status - Test Down | 2024-08-08 |
Test Status - Test Down | 2024-06-17 |
Test Status - Test Resumed | 2022-11-30 |