Procedure for Immunochromatographic Test SD Bioline Assay/Capillia/TBcID

This method detects the MPT64 antigen specifically produced by the M. tuberculosis complex. It detects MPT64 (A 24 kDa major culture filtrate protein), secreted by the M. tuberculosis cells during growth.

The kit is a test plate that consists of a carrier strip composed of: 

• a specimen placing area

• a reagent area containing a colloidal gold-labelled anti-MPT64 monoclonal antibody (mouse)

• a developing area where the anti-MPT64 monoclonal antibody (mouse) and an anti-mouse immunoglobulin polyclonal antibody (rabbit) is fixed

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A drop of the culture is put on the “specimen placing area” on the test plate. The colloidal gold labelled MPT64 antibody “A” dissolves and forms an immune complex with MPT64 antigens in the specimen. This immune complex migrates through the developing area by capillary action and is captured by the anti-MPT64 antibody “B” fixed in the reading area [T =Test]. The resultant complex forms a purple-red line of colloidal gold in the reading area [T]. This visually indicates the existence of MPT64 antigens in the specimen. On the other hand, whether or not MPT64 antigens exist in the specimen, excess colloidal gold labelled anti-MPT64 antibodies further migrate through the developing area and are captured by the anti-mouse immunoglobulin antibody (fixed antibody). The resultant complex forms a purple-red line of colloidal gold in the reading area [C = Control]. This means that the colloidal gold-labelled anti-MPT64 antibodies have migrated normally.

Precautions:

1. Use freshly prepared suspension for each quality control test. 

2. All work should be carried out in a proper biological safety cabinet.

3. All materials should be sterilized by autoclaving before disposal. 

4. Follow all the recommended safety precautions.

Resource

Mycobacteriology Laboratory Manual 

Assessment