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MYCOBACTERIUM TUBERCULOSIS COMPLEX/RIFAMPIN BY RT-PCR

Item Value
Available Stat? No
Test code MTBX
Performed by? Microbiology (AFB)
Sendout? No
Price range $$$$
In House Availability Specimen may be sent 24 hours/7days. Test is performed Monday - Friday, 7:30 am – 7:00 pm as specimens are received. At other times on Monday – Friday, and on weekends, evenings, holidays, assay will be performed as staffing allows.
Principle A qualitative Real Time (RT) PCR method is used to detect Mycobacterium tuberculosis complex gene sequences.
Interpretation Specimens with Mycobacterium tuberculosis complex target DNA and Rifampin resistance detected by RT-PCR are reported as:
POSITIVE. M. tuberculosis complex target DNA detected. Rifampin resistance DETECTED. Confirmatory testing by DNA sequencing recommended. Contact Microbiology Lab Medicine Resident for recommended testing (415-443-1438).

Specimens with Mycobacterium tuberculosis complex target DNA detected and Rifampin resistance not detected by RT-PCR are reported as:
POSITIVE. M. tuberculosis complex target DNA detected. Rifampin resistance NOT DETECTED.

Specimens with Mycobacterium tuberculosis complex target DNA not detected by RT-PCR are reported as:
NEGATIVE. M. tuberculosis complex target DNA not detected.

If internal controls or amplification steps do not give acceptable results, the assay results will be reported as:
INVALID. Presence or absence of MTB complex cannot be determined. Resubmit if clinically indicated.

Disclaimer:
A negative result does not rule out the presence of MTB complex from a sputum sample due to low numbers or inhibitors.
A positive test does not necessarily indicate the presence of viable organisms since the test may detect the nucleic acid of dead organisms.
This assay is FDA approved for the analysis of induced or expectorated sputa only.
This assay is also limited for use with specimens from patients who have not received anti-tuberculosis therapy and should not be used to monitor drug therapy.
This assay does not provide confirmation of rifampin susceptibility since there may be other mechanisms of rifampin resistance not detected by this test.
Container type Sterile, leak-proof, screw cap container, without preservatives or diluents.
Amount to Collect 3 - 5 mL
Sample type Sputum, expectorated or induced
Min. Volume 1 mL
Normal range NEGATIVE. M. tuberculosis complex target DNA not detected.
Synonyms MTB Complex PCR;MTB Complex/Rifampin by RT PCR; MTBX (GeneXpert)
Stability Deliver to Microbiology Lab (2M33) immediately after collection or hold at 4° C until delivery.
Causes for rejection 1. All other specimen types such as tracheal aspirates, bronchoalveolar lavage, wounds, abscesses, CSF, tissues and other specimen types are not acceptable. This assay is FDA approved only for the analysis of sputum.
2. Specimens received > 48 hours after collection time.
3. Specimens less than 1 mL.
4. Duplicate sputa collected on the same day.
5. Specimens with visible food particles.
6. Leaking specimens.
7. Unlabeled or improperly labeled specimens.
Turn around times 3 hours (see In House Availability)
References Xpert MTB/RIF Product Insert. Cepheid. Sunnyvale, CA. 301-14-4, Rev. A July 2013.
CPT coding 87556 / 87798
Last Updated 11/4/2015 1:33:41 PM
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