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Lab Test Dictionary

TB PCR Screen (AFB2)

Methodology

Real-time PCR or line probe assay

Synonyms

AFB; Acid Fast Bacili; Mycobacteria; Mycobacterial; MTB; TB; NAAT

Performing Lab

National Jewish Health (NJH) Mycobacteriology

Epic ID

LAB080029

Lab Test Days

1-3 Days

Standard TAT

Monday-Saturday

Collection Information

Container Type

Sterile Container

Collection Instructions

2 mL Sputum or Lower respiratory track (bronchoalveolar lavage, bronchial lavage, etc.) or 2 mL Body fluids (pericardial, synovial, pleural, etc.) or CSF, 1 g Fresh tissue or FFPE tissue, 2 mL Gastric lavage or wash or 2 mL Urine in a sterile container. For Fresh tissue, submerge in sterile non-bacteriostatic saline in a sterile container. For Gastric lavage/wash, Neutralize specimen within 4 hours of collection with 100 mg of sodium carbonate.

Processing Information - Lab Use Only

Transport Temperature

Room Temp-OK/Refrigerate-OK

Specimen Stability

Room Temp: Unacceptable (72 Hours for Fresh Tissue or Gastric lavage/wash); Refrigerated: 7 Days (Unacceptable for Fresh Tissue or Gastric lavage/wash); Frozen: Unacceptable

Rejection Criteria

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

Processing Instructions

Complete a NJH Mycobacteriology requisition form and submit with specimen Monday-Friday, no weekends or holidays. For Fresh tissue, submerge in sterile non-bacteriostatic saline in a sterile container. For Gastric lavage/wash, Neutralize specimen within 4 hours of collection with 100 mg of sodium carbonate.

Comments

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