Mycobacterium tuberculosis Susceptibility First Line Drugs
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| WSLH Department: | CDD - Communicable Disease Division |
| WSLH Test Code: | MM00204 |
| Day(s) Performed: | Monday - Friday |
| Turn-around Time: | 3-6 weeks |
| Recommended Uses: | To determine the in vitro susceptibility of M. tuberculosis complex organisms to first line antimicrobial agents. |
| Pre-approval: | N |
| Contraindications: | |
| Additional Tests Performed: |
| Preparation for Collection: | |
| Specimen Requirements: | M. tuberculosis complex isolate in broth or solid media |
| Collection Instructions: | |
| Collection Kit/Container: | |
| Requisition Form: |
CDD Requisition Form A
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| Required Information: | Identification of organism as a member of the M. tuberculosis complex. Laboratory regulations require the following minimum information to be provided on the requisition form for a specimen to be accepted for testing: Patient name or unique identifier; date and time of collection, patient date of birth and sex, specimen type/site of collection, test request(s), clinician name and UPIN, and address for reporting results. Please be certain that name/identifier on the form matches that on the specimen label. |
| Rejection Criteria: | |
| Specimen Handling: | Mycobacterium tuberculosis isolates should be packaged and transported according to the guidelines outlined for "Category A Infectious Substances." Cultures may be transported to the laboratory at ambient temperatures. Avoid temperature extremes during transport. |
| Packaging Requirements: | |
| Courier Information: | |
| Specimen Receiving Hours: | Monday-Friday 7:45 AM - 4:30 PM, Saturday 7:45 AM - 12:00 PM |
| Results Include: | M. tuberculosis complex organisms Susceptible or Resistant to the listed antimicrobial agents using criteria established by the Clinical and Laboratory Standards Institute (CLSI). |
| Limitations: | **Test can only be performed on pure M. tuberculosis complex isolates. Mixed or contaminated cultures will extend turnaround time significantly and may prevent susceptibility testing. |
| Additional Tests Recommended: | |
| Additional Comments: | **Isolates resistant to rifampin or two first-line drugs are automatically referred to CDC for second-line drug susceptibility testing. **The initial M. tuberculosis complex isolate is genotyped as part of the CDC universal genotyping program. **GeneXpert MTB/RIF will automatically be performed on all isolates submitted for 1st-line DST. The MGIT test used here has been approved by the U.S. Food and Drug Administration. However, MGIT and other growth-based susceptibility tests have known issues with false resistance and reproducibility of pyrazinamide. As a result, MTBC isolates scored as PZA resistant will be reported as PZA “Indeterminate” and will be sent to the Centers for Disease Control and Prevention (CDC) for pncA sequencing to determine if mutations known to confer PZA resistance are present. |
| Methodology: | MGIT broth method. This test has been approved by the U.S. Food and Drug Administration (FDA). |
| Includes: | Susceptibility tests of M. tuberculosis complex organisms with two concentrations of Isoniazid (I), one concentration of Ethambutol (E), Rifampin (R) and Pyrazinamide (PZA). |
| Regulatory Compliance: |
| CPT Code: | 87188x5 |
| Price: | $271.00 Price Effective 1/1/25 |
| Fee Exempt Eligible: | N |
| Billing and Revenue Office: | 1-800-862-1065 arbill@slh.wisc.edu |