LT-Microscopy & NAAT

After completion of the set number of nucleic acid extractions (i.e., buffer count 05/ 25/ 50/ 100 completed) the Trueprep AUTO v2 device will prompt the alert on its 2- line LCD screen to “Change the reagent pack” and “Insert Reagent Reset Card & Start” on the screen alternatively. When this happens, the new reagent pack needs to be inserted into the device and the buffer count needs to be reset.

Feedback after RBRC

Cartridge-based Nucleic Acid Amplification Test (CBNAAT) is used to detect Mycobacteria tuberculosis and rifampicin-resistance using GeneXpert IV Dx system and the Xpert MTB/ RIF cartridge.

The CBNAAT system integrates and automates sample processing, nucleic acid amplification, and detection of Mycobacteria tuberculosis and rifampicin resistance.

The system utilises the use of single-use disposable CBNAAT cartridges that hold the Polymerase Chain Reaction (PCR) reagents and hosts the PCR process.

The process involves the following steps:

In Ziehl-Neelsen microscopy, the carbol fuchsin fuchsin stain is heated to enable the dye to penetrate and bind the waxy mycobacterial cell wall. Following acid-decolourisation, the sputum smear is counterstained with methylene blue which stains the background material, providing a contrast blue colour against which the red AFB can be seen.

Introduction

Cartridge-based Nucleic Acid Amplification Test (CBNAAT) is an automated rapid molecular diagnostic test which detects targeted Deoxyribonucleic Acids (DNA) sequences of Mycobacterium tuberculosis (M.tb) genome by Real-time Polymerase Chain Reaction (RT-PCR) method.

The consumables required at a Cartridge-based Nucleic Acid Amplification Testing (CBNAAT) laboratory include the following:

CBNAAT/ GeneXpert Dx System consisting of CBNAAT machine preloaded with assay software, Computer and the Barcode reader

• Good quality sputum collection is of paramount importance in tuberculosis diagnosis.
• Once a person is identified as presumptive TB, s/he is referred to the Designated Microscopy Centre (DMC) for sputum collection.
• For TB diagnosis two sputum samples are collected - one is the supervised ‘spot’ sample collected at the DMC (labelled Specimen A) and the other is the early morning sample collected by patient themselves at his/her home (labelled Specimen B).