An AFB-DNA (TB-PCR) Detection by Real-Time PCR with Reflex to Rifampicin Resistance by Ultra CBNAAT on Sputum is a premier, ultra-sensitive molecular test for diagnosing Pulmonary Tuberculosis (TB).

While traditional microscopic smears look for the physical bacterium under a lens, this advanced panel directly extracts and copies the genetic blueprint (DNA) of the Mycobacterium tuberculosis complex. It stands as a vital frontline diagnostic tool because it rapidly answers two clinical questions directly from a sputum sample: Is the patient infected with TB? and if so, Will standard first-line antibiotics work against it?

Deconstructing the Test Terminology
AFB-DNA (TB-PCR) by RTPCR: The laboratory uses Real-Time Polymerase Chain Reaction to replicate specific genetic sequences unique to TB. Because it amplifies target DNA millions of times, it can detect the presence of the bacteria even if the patient has a very low bacterial load (paucibacillary sputum), which a standard microscope smear would completely miss.

Reflex to Ultra CBNAAT: "Reflexing" means the laboratory automation software automatically launches a secondary, deeper test only if the initial PCR screen detects TB DNA. The patient does not need to return to give a second sample.

Ultra CBNAAT (Cartridge-Based Nucleic Acid Amplification Test): This refers specifically to the newer GeneXpert MTB/RIF Ultra technology. The "Ultra" cartridge features an increased sample chamber volume and nested PCR technology, providing unmatched sensitivity.

Rifampicin Resistance: Rifampicin is a cornerstone drug in standard anti-tubercular therapy. The Ultra assay maps the bacterial rpoB gene to check for mutations that make the bacteria immune to Rifampicin. Resistance to this drug is a critical marker for Multidrug-Resistant Tuberculosis (MDR-TB).