Cartridge-based nucleic acid amplification test useful for early diagnosis of extrapulmonary tuberculosis

The main aim of this study was to establish the usefulness of CBNAAT in diagnosing EPTB cases early.

For eight months, the team conducted a comparative study at a rural tertiary care hospital in West Bengal, India. The samples collected from different sites were pleural fluid, lymph nodes, cerebrospinal fluid (CSF), pus, ascitic fluid, and tissue aspirate. They were subjected to both CBNAAT and smear staining and examination under a fluorescent microscope. Positive samples were cultured, examined, and compared.

The key results of this study are:

• From 593 samples collected from different sites in suspected cases of EPTB—52 samples were positive by CBNAAT.
• Six cases demonstrated rifampicin resistance (RIF resistant).
• Smear staining of the samples by auramine-rhodamine stains and examined under the fluorescent microscope for acid-fast bacilli identifying 33 samples; the rest were negative.
• Lowenstein–Jensen media was used to culture Slides showing acid-fast bacilli.

They said CBNAAT is a very useful assay for diagnosing extrapulmonary cases early. It accurately identifies false negative samples by smear microscopy.

Our study found that EPTB cases are more in females than males.

The only limitation of the study was “more detailed study for over one year was not done.” they noted

Further reading:

https://www.japi.org/x2f4d4c4/diagnostic-approach-to-extrapulmonary-tuberculosis-by-cartridge-based-nucleic-acid-amplification-test