Rapid, qualitative susceptibility testing of Mycobacterium tuberculosis complex isolates growing in pure culture
Affirming the initial choice of chemotherapy for M tuberculosis infections
Confirming the emergence of drug resistance
Guiding the choice of alternate agents for therapy for M tuberculosis infections
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
STV2 | Susceptibility, Mtb Cx, 2nd Line | No, (Bill Only) | No |
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
STV1 | Susceptibility, Mtb Complex, Broth | 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 for confirmation of resistance and 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 for confirmation of resistance and second line agents will be performed and charged.
Varies
CTB / Mycobacteria and Nocardia Culture or CTBID / Culture Referred for Identification, Mycobacterium and Nocardia must also be ordered and will be charged separately unless identification of organism is provided.
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.
Other | Agar plate |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | ||
Refrigerated |
Rapid, qualitative susceptibility testing of Mycobacterium tuberculosis complex isolates growing in pure culture
Affirming the initial choice of chemotherapy for M tuberculosis infections
Confirming the emergence of drug resistance
Guiding the choice of alternate agents for therapy for M tuberculosis infections
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 for confirmation of resistance and second line agents will be performed and charged.
Primary treatment regimens for Mycobacterium tuberculosis complex often include isoniazid, rifampin, ethambutol, and pyrazinamide. Susceptibility testing of each M tuberculosis complex isolate against these first-line antimycobacterial agents is a key component of patient management.
In vitro susceptibility testing methods are available to assess the susceptibility of M tuberculosis complex isolates to selected antimycobacterial agents. The Clinical Laboratory Standards Institute (CLSI) provides consensus protocols for the methods, antimycobacterial agents, and critical concentrations of each agent to be tested in order to permit standardized interpretation of Mm tuberculosis complex susceptibility testing results. Current recommendations indicate that laboratories should use a rapid broth method in order to obtain M tuberculosis susceptibility data as quickly as possible to help guide patient management. Resistance, as determined by rapid testing, must be confirmed by another method or by another laboratory.
This test uses an FDA-cleared commercial system for rapid broth susceptibility testing of M tuberculosis complex and assesses resistance to antimycobacterial drugs at the 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 (0.1 mcg/mL) but not exhibiting resistance to high levels (0.4 mcg/mL) 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.
For resistant organisms, confirmatory testing is automatically performed by minimum inhibitory concentration for isoniazid, rifampin, and ethambutol.
1. Blumberg HM, Burman WJ, Chaisson RE, et al: American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America: treatment of tuberculosis. Am J Respir Crit Care Med 2003;167(4):603-662
2. CLSI: Susceptibility Testing of Mycobacteria, Nocardiae, and Other Aerobic Actinomycetes; Approved Standard. CLSI document M24-A (ISBN 1-56238-550-3). CLSI, Wayne, PA, 2003
3. Inderlied CB, Pfyffer GE: Susceptibility test methods: Mycobacteria. In Manual of Clinical Microbiology. Eighth edition. Edited by PR Murray, EJ Baron, JH Jorgensen, et al. Washington, DC, ASM Press, 2003, pp 1149-1177
4. LaBombardi VJ: Comparison of the ESP and BACTEC Systems for testing susceptibilities of Mycobacterium tuberculosis complex isolates to pyrazinamide. J Clin Microbiol 2002;40:2238-2239
This test method is based on presence or absence of growth of Mycobacterium tuberculosis in broth cultures with the presence of critical concentrations of the antimycobacterial drugs isoniazid, rifampin, and ethambutol. One of 2 FDA-cleared platforms may be used.
The VersaTrek platform uses the presence or absence of a pressure increase inside broth vials containing M tuberculosis in the presence of critical concentrations of the antimycobacterial drugs isoniazid, rifampin, and ethambutol. Increasing pressure indicates the presence of actively growing M tuberculosis that is resistant to the critical concentration of drug contained in the broth. Low or undetectable pressure increases in the presence of critical drug concentrations suggests a lack of M tuberculosis growth and susceptibility to the drug at the tested concentration. Antimycobacterial drugs and concentrations tested are: isoniazid (0.1 mcg/mL and 0.4 mcg/mL), rifampin (1 mcg/mL), and ethambutol (5 mcg/mL and 8 mcg/mL).(Package insert: VersaTREK Mycobacteria Detection and Susceptibility Testing system, TREK Diagnostics, Cleveland, OH 2014)
The BACTEC MGIT 960 platform uses the production and measurement of fluorescence within a Mycobacterial Growth Indicator Tube (MGIT) in the presence of actively growing M tuberculosis complex isolates in the presence of critical concentrations of the antimycobacterial drugs isoniazid, rifampin, and ethambutol. Low or undetectable levels of fluorescence in the presence of critical drug concentrations suggests lack of M tuberculosis growth and susceptibility to the drug tested at the tested concentration. Increased fluorescence suggests active growth of M tuberculosis and resistance to the drug at the tested concentration. Antimycobacterial drugs and concentrations tested are: isoniazid (0.1 mcg/mL and 0.4 mcg/mL), rifampin (2 mcg/mL), and ethambutol (5 mcg/mL).(Package insert: BACTEC MGIT 960 SIRE Kit, BD Diagnostics, Sparks, MD 2016)
A separate test (TBPZA) is available for testing of the other first-line agent pyrazinamide.
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
87186-Susceptibility, Mtb Cx, 2nd Line (if appropriate)
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 Resumed | 2022-11-30 |
Test Status - Test Down | 2022-01-20 |