LT-Microscopy

Feedback after RBRC

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.

• 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).

Sputum smear microscopy is an integral part of the National TB Elimination Programme's (NTEP’s) diagnostic services and can majorly impact the success of the programme.

It is essential to have a credible and well-established quality assurance system to assess the performance of the microscopy service.

NTEP has implemented a multi-level quality assurance network system of sputum smear microscopy in the country consisting of: 

1. Internal Quality Control (IQC)
2. External Quality Assessment (EQA)
3. Quality Improvement (QI)

• Designated Microscopy Centres (DMCs) are the most peripheral laboratory under the National TB Elimination Programme (NTEP) network. Therefore, it is very important for the DMCs to maintain an adequate stock of all consumables.
• A paper-based stock register is maintained at the DMC and submitted as a part of the ‘Monthly report on programme management, logistics and microscopy’.

The monthly abstract is a recording format filled and printed in the Designated Microscopy Centre (DMC) Tuberculosis (TB) laboratory register. Every month after the last day, the laboratory technician (LT) summarizes the information on sputum smear examinations done during that month, using the monthly abstract format.

• Designated Microscopy Centres (DMCs) are the most peripheral laboratory under the National TB Elimination Programme (NTEP) network.
• Any person identified to be a presumptive TB patient is first referred to the nearest DMC for sputum examination or their sputum specimens are collected and transported to the DMC. Therefore, it is very important for the DMCs to maintain an adequate stock of reagents and other consumables.
• The Medical Officer (MO) of DMC is responsible for determining the number of reagents and other materials the DMC needs every month.