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Test ID MTBPZ Mycobacterium tuberculosis Complex, Pyrazinamide Resistance by pncA DNA Sequencing

Infectious

Useful For

Detection of genotypic resistance to pyrazinamide by Mycobacterium tuberculosis complex isolates

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
MTBVP Mtb PZA Confirmation, pnc A Sequence No, (Bill Only) No

Testing Algorithm

When this test is ordered, the reflex test may be performed and charged.

Method Name

DNA Sequencing

Reporting Name

Mtb PZA Resistance, pncA Sequencing

Specimen Type

Varies

Specimen Type: Organism

Container/Tube: Middlebrook 7H10 agar slant

Specimen Volume: Isolate

Collection Instructions:

1. Organism must be in pure culture, actively growing.

2. Place specimen in a large infectious container (Supply T146) and label as an etiologic agent/infectious substance.

Additional Information:

1. Specimen source and suspected organism identification are required.

2. See Infectious Specimen Shipping Guidelines in Special Instructions for shipping information.

Forms: If not ordering electronically, complete, print, and send a Microbiology Test Request Form (T244) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/microbiology_test_request_form.pdf).

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)
  Refrigerated 

Clinical Information

The protein product of the Mycobacterium tuberculosis complex pncA gene is an enzyme that is responsible for activation of the prodrug pyrazinamide (PZA). DNA sequencing of the Mycobacterium tuberculosis complex pncA gene can be used to detect mutations that correlate with in vitro PZA resistance.(1,2) The sequencing result can be available in as little as 1 day after the Mycobacterium tuberculosis complex isolate grows in culture, thereby providing a more rapid susceptibility result than the average 10 to 14 days required by phenotypic broth methods.

Reference Values

Pyrazinamide resistance not detected

Cautions

According to the literature,(3) 72% to 97% of pyrazinamide (PZA)-resistant clinical isolates carry mutations in the pncA gene or promoter region. However, other resistance mechanisms (eg, changes in PZA uptake or increased PZA efflux) will not be detected by this method.  

 

Correlation of the in vitro sequencing result with clinical presentation is strongly recommended.

Day(s) Performed

1 day per week, Varies

Report Available

7-14 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

87153-Mtb PZA Confirmation, pncA Sequence

NY State Approved

Yes