Clinical Specimen Submission Guidance

Submit all specimens to 50 Orms St, Providence RI 02904. Open Monday to Friday 8:30 AM to 4:30 PM

Mycobacterium tuberculosis
Lab Special Pathogens & Biothreats Laboratory 401-222-5586
Pathogen

Mycobacterium tuberculosis

Disease Tuberculosis (TB)
Test Description

Specimens: Smear (fluorochrome stain) for presence of acid fast bacilli and culture (liquid and solid media) for presence of Mycobacterium spp.

Nucleic acid amplification testing (NAAT) (i.e. TB PCR) is available for specimens from patients meeting the CDC recommended guidelines for testing. Refer to M. tuberculosis (NAAT) Frequently Asked Questions at: http://www.health.ri.gov/diseases/tuberculosis/for/laboratorians/#tb

Isolates: Identification/speciation by nucleic acid (DNA) probe (M.TB-complex, M. avium complex, M. gordonae) . Mycobacteria isolates that are not identified by probe by the RISHL, and meet the criteria for identification by CDC, are forwarded to CDC for identification by molecular means.

Drug Susceptibility Testing: Isolates of M. tuberculosis complex only are forwarded to a CDC-designated reference laboratory for susceptibility testing. Contact the Mycobacteriology section of the Special Pathogens Lab at (401) 222-5587 for further information regarding susceptibility testing on Mycobacterium species.

Special Instructions

TB PCR

Sputum

The Cepheid Xpert MTB/RIF Assay uses nested real-time PCR to detect MTB-complex DNA and rifampin-resistance associated mutations of the MTB-complex rpoB gene. The Xpert MTB/RIF Assay has been cleared by the U.S. Food and Drug Administration (FDA) and the performance characteristics were validated by the Rhode Island State Health Laboratories.

Non-Sputum respiratory specimens (bronchial washing/lavage, bronchioalveolar lavage, lung washing, bronchial brushing)

The Cepheid Xpert MTB/RIF Assay used nested real-time PCR to detect MTB-complex DNA and rifampin-resistance associated mutations of the MTB-complex rpoB gene. The performance of the Xpert MTB/RIF Assay was validated by the Rhode Island State Health Laboratories for additional non-sputum respiratory specimens that have not been approved nor cleared by the U.S. Food and Drug Administration (FDA). Namely, bronchial washing/lavage, bronchioalveolar lavage, lung washing, and bronchial brushing.

AFB confirmation

The Cepheid Xpert MTB/RIF Assay uses nested real-time PCR to detect MTB-complex DNA and rifampin-resistance associated mutations of the MTB-complex rpoB gene. The performance of the Xpert MTB/RIF Assay for the identification of MTB-complex isolates for AFB positive culture was validated by the Rhode Island State Health Laboratories. The testing of AFB positive cultures using this assay has not been approved nor cleared by the U.S. Food and Drug Administration (FDA).

RESULT INTERPRETATION

Refer to "https://health.ri.gov/publications/guidance/TBNucleicAcidImplificationTestingInterpretation.pdf"

Specimen

Specimens: Refer to Rhode Island State Health Laboratories "Guidelines for the Collection and Transport of Specimens for Tuberculosis Testing."

TB PCR: must meet CDC recommended guidelines (see Test Description)

Isolate: 4 mL liquid media, Lowenstein-Jensen slant or Middlebrook 7H-10 or 7H-11 slant/plate is also acceptable

CLIA regulations require two patient identifiers on the specimen container and the test requisition

Form Required

Rhode Island State Health Laboratories (RISHL) test requisition form http://www.health.ri.gov/laboratorytesting

Test Request

Specimens: AFB Smear & Culture

TB PCR (requires AFB smear and culture)

Isolates: AFB Identification

Transport

Refer to Rhode Island State Health Laboratories "Guidelines for the Collection and Transport of Specimens for Tuberculosis Testing."

Specimens and isolates must be in leak proof containers with properly fastened screw caps. Isolates in liquid media are to be sealed with parafilm or other appropriate barrier film.

Specimens must be packaged & transported in accordance with current federal shipping regulations.

Containers specifically labeled for transport of specimens and isolates to the RISHL Mycobacteriology Laboratory are available in all Microbiology Laboratories and Laboratory Sendout departments.

Shipments that meet the definition for 'Category A' infectious substances as defined by federal regulation require additional packaging/labeling.

Normal Value

Smear: Smear negative for acid-fast bacilli (AFB)

Culture: Culture negative for Mycobacterium species

TB PCR: DNA of Mycobacterium tuberculosis complex is not detected

Reporting Requirement Providers must report patient information on Tuberculosis within 4 days using the RIDOH reportable disease form.
Turnaround Time

Smear: within 1 working day of specimen receipt

PCR: within 2 working days

Culture: culture plates are held for 8 weeks before being reported as negative for growth of Mycobacterium species

Isolate identification: DNA probe testing is performed within 1 working day of isolate receipt

Antimicrobial Susceptibility Testing: Testing performed at a CDC-designated reference laboratory.

Kit Kits are available from the RISHL Center for Laboratory Support Services and may be obtained Monday - Friday between 8:30 am and 4:30 pm. Test order forms can be faxed to (401) 222-6985