Mycobacterium tuberculosis complex PCR
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| WSLH Department: | CDD - Communicable Disease Division |
| WSLH Test Code: | MM00256 |
| Day(s) Performed: | Monday - Friday |
| Turn-around Time: | 1-3 days |
| Recommended Uses: | CDC recommends that NAAT (PCR) be performed on at least one respiratory specimen from each patient with signs and symptoms of pulmonary tuberculosis (TB) for whom diagnosis of TB is being considered but has not yet been established, and for whom the test would alter case management or TB control activities, such as contact investigations (MMWR. 2009; 58: 7-10). |
| Pre-approval: | No |
| Contraindications: | • Specimens from patients who have received TB antimicrobial therapy for more than 7 days in the past 12 months are not appropriate for this assay. • Patients for whom suspicion of TB is low. • Not to be used for test of cure. • Not to be used for decisions to release patients from airborne isolation. • This test is not intended for screening asymptomatic contacts of TB patients or for screening smear-negative pulmonary specimens from patients diagnosed with extra-pulmonary TB. |
| Additional Tests Performed: |
GeneXpert MTB/RIF testing will automatically be performed on any TB-positive pulmonary specimens |
| Preparation for Collection: | Collect specimens prior to anti-mycobacterial drug treatment or within 7 days of start of therapy. Sterile preparation of site if applicable. |
| Specimen Requirements: | Submit 3-10 mL of a primary respiratory specimen (sputum, tracheal aspirate, bronchial washings, BAL). Specimens with visible blood will be accepted. If AFB smear has not been performed, WSLH will perform AFB smear and culture testing and the submitter will be billed. Submit 0.5 mL of decontaminated and/or concentrated sediment. All specimens should be submitted in sterile, leak-proof containers. If a specimen from a non-sterile site has not been decontaminated, WSLH will perform decontamination and the submitter will be billed. TB PCR must be performed within 7 days of specimen collection. |
| Collection Instructions: | Sputum: Collect three specimens, each collected in 8-24 hour intervals with at least one being an early morning specimen (CDC MMWR 2005: 54, RR-17). Optimally 5 mL of sputum, minimum 3 mL. Sputum specimens collected less than 8 hours apart will be pooled into a single smear and culture. Gastric Lavage: Collect fasting specimen soon after patient awakens in order to obtain sputum swallowed during sleep; place in neutralizing buffer immediately. |
| Collection Kit/Container: |
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| Requisition Form: |
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| Required Information: | 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 which is required to have a minimum of two identifiers. |
| Rejection Criteria: | Specimens from patients who have received TB drug treatment for more than 7 days in the past 12 months should not be submitted for this assay. Specimens from patients with known TB or NTM infections should not be submitted for this assay unless it has been >12 months since their last positive AFB smear or culture. AFB smear-negative extrapulmonary specimens are not tested. This test is only performed on primary specimen material; positive cultures are not acceptable for this testing. Concentrated sediment volume of less than 0.2 mL is not acceptable for this testing. |
| Specimen Handling: | Store specimens at refrigerated (2-8°C). Ship with frozen cold pack(s). Use pressure-resistant bags as inner packaging. |
| Packaging Requirements: | |
| Courier Information: | Specimens submitted for surveillance or at the request of a public health department are eligible for fee-exempt courier. Contact Purple Mountain Dispatch at 800-990-9668 for specimen pickup. |
| Specimen Receiving Hours: | Monday-Friday 6:00 AM - 4:30 PM, Saturday 6:30 AM - 12:30 PM |
| Results Include: | Mycobacterium tuberculosis complex DNA detected; No Mycobacterium tuberculosis complex DNA detected; Inhibitors of PCR present in the specimen; Equivocal |
| Limitations: | This real-time PCR assay detects the presence of M. tuberculosis complex DNA in clinical specimens. It detects a target within an insertion sequence (IS6110), which is specific for, but does not differentiate among, members of M. tuberculosis complex. In very rare M. tuberculosis complex strains, this target may be absent. A negative result does not rule out infection with M. tuberculosis complex. |
| Additional Tests Recommended: | TB PCR should always be performed in conjunction with Mycobacteria AFB Smear and Culture (Test Code MM00250). For smear-positive, TB PCR-negative results, consider testing a second specimen to confirm the PCR result. No more than two specimens should be tested total. |
| Additional Comments: |
| Methodology: | This real-time PCR assay detects the presence of M. tuberculosis complex DNA in clinical specimens. It detects a target within an insertion sequence (IS6110), which is specific for members of M. tuberculosis complex. |
| Includes: | Nucleic acid amplification (NAAT) real-time PCR for direct detection of M. tuberculosis complex DNA in human respiratory and non-respiratory specimens. |
| Regulatory Compliance: |
| CPT Code: | 87556 |
| Price: | $307.00 |
| Fee Exempt Eligible: | Yes, pre-approval required. Contact the WI State TB Program at 608-261-6319. Patients must meet the Wisconsin TB Control Program criteria and be WI residents to qualify for fee-exempt testing. Patient must have signs and symptoms of pulmonary TB. Patient must be reported to the local or state public health department as a suspect TB case. Patient must be in respiratory isolation. Patient must not have been diagnosed with TB or a non-tuberculous mycobacterial (NTM) infection within the last 12 months. Patient must have received ≤7 days of anti-mycobacterial therapy or no such treatment within the last 12 months. |
| Billing and Revenue Office: | 1-800-862-1065 arbill@slh.wisc.edu |