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Nucleic Acid Amplification Test (NAAT) for M. tuberculosis from clinical specimens

Test Code

NAAT or AFB2c (Old code: AFB2)

Description

This test detects M. tuberculosis complex and rifampin resistance from a specimen using nucleic acid amplification testing (NAAT). The NAAT is performed to rapidly rule-in or rule-out M. tuberculosis complex infection, identify resistance to rifampin, and triage potentially infected patients appropriately for airborne isolation. It should not be used as a test of cure.

The Centers for Disease Control and Prevention (CDC) recommends that NAAT should be performed on at least one respiratory specimen from each patient with signs and symptoms of pulmonary TB for whom a diagnosis of TB is being considered but has not yet been established, and for whom the test result would alter case management or TB control activities.

This test is automatically included as part of AFB1, the full AFB workup. It can be ordered separately or added-on to another test.

Collection/Transport

Collect

Specimen	Volume	Method	Total stability time including transport
Sputum (expectorated or induced)	2 mL	Real-time PCR	7 days refrigerated; 72 hours ambient.
Lower respiratory tract specimen (e.g. bronchoalveolar lavage, bronchial washes etc.)	2 mL	Real-time PCR
Body fluids (pericardial, synovial, pleural etc.)	2 mL	Line Probe
Cerebrospinal fluid (CSF)	2 mL	Real-time PCR	72 hours ambient. This source should not be refrigerated.
Fresh Tissue	1 g	Line Probe
FFPE Tissue	1 g	Line Probe
Gastric lavage or wash	2 mL	Line Probe
Urine	2 mL	Real-time PCR	7 days refrigerated.

Unacceptable Conditions

Specimen received with <1.5 mL volume.
Saliva
Frozen specimen
Swabs
Blood specimen
Stool specimen

Notes

The Centers for Disease Control and Prevention (CDC) recommends that NAAT should be performed on at least one respiratory specimen from each patient with signs and symptoms of pulmonary TB for whom a diagnosis of TB is being considered but has not yet been established, and for whom the test result would alter case management or TB control activities.

TB NAAT is not performed on swabs, stool, or blood specimens.

Test Detail

Performed

Typically all days.

Methodology

Real-time PCR or line probe assay

Turnaround Time

Results are typically reported in less than a day, but may be 1-3 days for non sputum sources.

Lab Department

Infectious Disease Laboratory, Mycobacteriology

Synonyms

Mycobacterial PCR, Tuberculosis PCR , MDR, TB PCR, MTB PCR

Related Tests

This test is a component of AFB1; MTB4 is a genotypic assay to detect resistance markers to first line drugs.

Sputum: FDA approved. Validated LDT for other sources (see Method in Collection Requirements).
Non-sputum sources: NYS waiver required for samples sent from NYS.

Result Interpretation

Reference Interval

M. tuberculosis complex not detected.

Interpretive Data

M. tuberculosis complex may be Detected, Not Detected, or Indeterminate.
Rifampin resistance may be Detected, Not Detected or Indeterminate. In cases where the line probe assay is used instead of real-time PCR, rifampin resistance is Present, Not Present, or Indeterminate. Isoniazid may also be reported.

Fees/Coding

CPT Code

Test	Method	CPT code	Billing code	When is this applied?
NAAT or AFB2C	Real-time PCR	87556	AFB2C	On sources where real-time PCR can be used. See "Method" under Collection Requirements.
NAAT or MTB4	Line Probe	87798 x 2	MTB4S	On sources where the line probe can be used. See "Method" under Collection Requirements.

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Nucleic Acid Amplification Test (NAAT) for M. tuberculosis from clinical specimens

Test Code

Description

Collection/Transport

Collect

Unacceptable Conditions

Notes

Test Detail

Performed

Methodology

Turnaround Time

Lab Department

Synonyms

Related Tests

Result Interpretation

Reference Interval

Interpretive Data

Fees/Coding

CPT Code

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Overview Search Tests

Nucleic Acid Amplification Test (NAAT) for M. tuberculosis from clinical specimens

Test Code

Description

Collection/Transport

Collect

Unacceptable Conditions

Notes

Test Detail

Performed

Methodology

Turnaround Time

Lab Department

Synonyms

Related Tests

Result Interpretation

Reference Interval

Interpretive Data

Fees/Coding

CPT Code

Recently Viewed Tests

Overview

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