Test ID: MTBV2
Antimicrobial Susceptibility, Mycobacterium tuberculosis Complex, Broth Method
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Rapid, qualitative susceptibility testing of Mycobacterium tuberculosis complex isolates growing in pure culture
Affirming the initial choice of chemotherapy for Mycobacterium tuberculosis infections
Confirming the emergence of drug resistance
Guiding the choice of alternate agents for therapy for Mycobacterium tuberculosis infections
Additional Tests Lists test(s) that are always performed, at an additional charge, with the initial test(s)
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| STV | Susceptibility, Mtb Complex, Broth | No, (Bill Only) | Yes |
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
When this test is ordered, the reflex test will be performed and charged.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Broth Dilution at Critical Drug Concentrations
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
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)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen Type: Organism
Container/Tube: Middlebrook 7H10 agar slant
Specimen Volume: Isolate
Collection Instructions:
1. Organism must be in pure culture, actively growing.
2. Place specimen in a large infectious container (Supply T146) and label as an etiologic agent.
Additional Information:
1. Specimen source and suspected organism identification are required.
2. CTB/8205 Mycobacterial Culture or CTBID/80278 Culture Referred for Identification, Mycobacterium must also be ordered and will be charged separately unless identification of organism is provided.
3. See Infectious Specimen Shipping Guidelines in Special Instructions for shipping information.
Forms: If not ordering electronically, submit a Microbiology Request Form (Supply T244) with the specimen.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | Agar plate |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Ambient (preferred) | |
| Refrigerated | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Primary treatment regimens for Mycobacterium tuberculosis complex often include isoniazid, rifampin, ethambutol, and pyrazinamide. Susceptibility testing of each Mycobacterium 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 Mycobacterium 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 Mycobacterium tuberculosis complex susceptibility testing results. Current recommendations indicate that laboratories should use a rapid broth method in order to obtain Mycobacterium 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 Mycobacterium tuberculosis complex and assesses resistance to the following antimycobacterial drugs at the critical concentrations indicated: isoniazid (0.1 mcg/mL and 0.4 mcg/mL), rifampin (1 mcg/mL), ethambutol (5 mcg/mL and 8 mcg/mL), and pyrazinamide (300 mcg/mL).
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Results are reported as susceptible or resistant.
Interpretation Provides information to assist in interpretation of the test results
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.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
For resistant organisms, confirmatory testing is automatically performed by the method of indirect proportion for isoniazid, rifampin, and ethambutol. Pyrazinamide resistance is confirmed by pncA DNA sequencing.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
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
Method Description Describes how the test is performed and provides a method-specific reference
This method is based on presence or absence of a pressure increase inside broth vials containing Mycobacterium tuberculosis in the presence of critical concentrations of the antimycobacterial drugs isoniazid, rifampin, ethambutol, and pyrazinamide. Increasing pressure indicates the presence of actively growing Mycobacterium 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 Mycobacterium tuberculosis growth and susceptibility to the drug at the tested concentration.(VersaTREK Mycobacteria Detection and Susceptibility Testing system, TREK Diagnostics, Cleveland, OH)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Varies
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
Antimicrobial Susceptibility, Mycobacterium tuberculosis Complex, Broth Method
87188 x 4
Susc, Mtb MOP, 1 drug
87190 (if appropriate)
Mtb PZA Confirmation, pcnA Sequencing
87153 (if appropriate)
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| MTBV2 | Susceptibility, Mtb Complex, Broth | In Process |
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