Role of CBNAAT in Diagnosing TB Meningitis

Diagnostic Performance of CBNAAT in TB Meningitis

CBNAAT has approximately 62% sensitivity for detecting TB in cerebrospinal fluid, meaning it misses about 38% of true TB meningitis cases 1
Specificity is excellent at approximately 98%, indicating that false-positive results are rare (only about 2%) 1
A positive CBNAAT result can be used as evidence of TB meningitis and guide decision-making because false-positive results are unlikely 1
However, a negative CBNAAT result cannot be used to exclude TB meningitis because false-negative results are exceedingly common due to the paucibacillary nature of the disease 1

Provides results within 24-48 hours compared to culture which takes 2-6 weeks 2
Can detect the presence of M. tuberculosis bacteria weeks earlier than culture for 80-90% of patients whose TB is ultimately confirmed by culture 2
Earlier laboratory confirmation of TB can lead to earlier treatment initiation, improved patient outcomes, and increased opportunities to interrupt transmission 2

Collect cerebrospinal fluid (CSF) specimens from patients with suspected TB meningitis and perform CBNAAT on CSF as a first-line rapid diagnostic test 1
If CBNAAT is positive: Diagnose as TB meningitis and initiate appropriate treatment immediately 1
If CBNAAT is negative: Cannot exclude TB meningitis; consider empiric treatment based on clinical features and other laboratory findings 1