Pathology Handbook

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Alternative Names:

TB PCR

Laboratory:

Microbiology

Test Code:

MTB

Specimen Types:

Bronchoalveolar Lavage
Bronchial Washings
Nasopharyngeal Aspirate
Cerebrospinal Fluid
Urine random
Tissue
Paraffin Block Shavings

Container Types:

Plain 70mL pot
CSF Tube 3

Collection & Request Instructions:

Mycobacterial culture should also be requested

The use of nucleic acid amplification tests (NAAT) for screening specimens from patients with suspected TB should be limited to:

Respiratory smear-positive specimens where the result is likely to influence clinical (treatment) and/or public health (isolation, contact investigation) decisions;
Respiratory smear-negative specimens from a patient with a high probability of TB, when prompt management and public health decisions are required; and
Selected non-respiratory specimens (e.g. meningeal, some tissue biopsies) where a prompt management decision is necessary (recognised that such tests have not been validated or approved).

The use of NAAT is considered inappropriate in the following instances:

When a patient is respiratory smear-negative and has a low probability of TB;
When a patient is respiratory smear-positive and has a very high probability of TB;
Paucibacillary non-respiratory specimens (e.g. pleural fluid, ascitic fluid).

Transport Instructions:

Room Temperature