Test Id : TB1LN
Effective August 05, 2025: This test is temporarily unavailable due to assay performance issues. The downtime is expected to be >30 days. Order TB2LN as an alternative. See test notification here.
Antimicrobial Susceptibility, Mycobacterium tuberculosis Complex, First Line, Varies
Useful For
Suggests clinical disorders or settings where the test may be helpful
Susceptibility testing of Mycobacterium tuberculosis complex isolates growing in pure culture.
Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.
| Test Id | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TB2LN | Susceptibility, Mtb Complex, 2 Line | Yes | No |
Additional Tests
Lists tests that are always performed, at an additional charge, with the initial tests.
| 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 |
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
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.
Method Name
A short description of the method used to perform the test
Broth Dilution at Critical Drug Concentrations
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
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)
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
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.
Specimen Type
Describes the specimen type validated for testing
Varies
Ordering Guidance
If testing for the first-line agent pyrazinamide is desired, order MTBPZ/Mycobacterium tuberculosis Complex, Pyrazinamide Resistance by pncA DNA Sequencing, Varies.
Additional Testing Requirements
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.
Shipping Instructions
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.
Necessary Information
Specimen source and suspected organism identification are required.
ORDER QUESTIONS AND ANSWERS
| Question ID | Description | Answers |
|---|---|---|
| Q00M0072 | Specimen source (Required) and Organism Identification (Required unless concurrent identification test is ordered) |
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Specimen Type: Organism
Supplies: Infectious Container, Large (T146)
Container/Tube: Middlebrook 7H10 agar slant
Specimen Volume: Isolate
Collection Instructions:
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Agar plate | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Refrigerated | |||
Useful For
Suggests clinical disorders or settings where the test may be helpful
Susceptibility testing of Mycobacterium tuberculosis complex isolates growing in pure culture.
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
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.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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.
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 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.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Isolates not received in pure culture may have delayed results because isolation is required prior to testing.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
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
Method Description
Describes how the test is performed and provides a method-specific reference
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. The FDA-cleared platform BACTEC MGIT 960 (Becton Dickinson) is 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)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Sunday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
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
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
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 instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
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.
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 Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
87188 x 3-Antimicrobial Susceptibility, Mycobacterium tuberculosis Complex, Broth Method
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| 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 |