February 7, 2022

Western Blot Test: Uses, Result, Cost, and More

Western blot is a technique used for protein detection from a mixture of proteins and has its application in immunology, molecular biology, biochemistry, and cell biology fields.

Western blotting is used for the confirmatory medical diagnosis of various infectious diseases and, to name a few, HIV, bovine spongiform encephalopathy (BSE), hepatitis C (HCV), syphilis, and autoimmune disorders.

As per WHO guidelines, this technique has been widely used as a more specific & supplemental assay on samples found initially reactive using ELISA and other screening tests for HIV. The Western Blot test is the confirmatory test to detect antibodies to HIV (Human immunodeficiency virus), the causative agent of AIDS (Acquired Immunodeficiency Syndrome). HIV Testing is performed using screening test; Rapid /ELISA and samples found reactive in these tests are confirmed for their status by Western blot.


The test is run on strips blotted with HIV viral antigens, and the blue color bands appear on the strip after the test is completed due to the use of Alkaline phosphatase enzyme and BCIP –NBT substrate in the process. The results are interpreted as Negative, Positive, or Indeterminate based on the presence of bands on the strip at the corresponding HIV Antigen;.Envelope (gp120,gp160,gp41), GAG (p17,p24&p55) and POL(p51, p31 & p66).

For a sample to be HIV Positive, a Control band and at least 2 HIV envelope bands along with any 1 GAG or 1 POL band shall be present on the strip. Suppose the band does not meet the positive criteria, i.e., either presence of 1 envelope band and GAG &/or POL band or only GAG OR POL band. In that case, the sample is interpreted as INDETERMINATE for HIV. The presence of only the control band is interpreted as HIV Negative.

The test is simple and can be performed in small setup labs as only a rotary shaker is required to complete the test. Furthermore, there is provision to run 1 test at a time, and hence it is cost-effective with a turnaround time of 5 hours since results can be obtained within 3-4 hours.

J Mitra & Co. offers HIV 1& 2 Western Blot (Confirmatory test kit ) to diagnose HIV in Human serum /plasma. It is the only Indian company manufacturing confirmatory tests for HIV antibodies.

The product is indigenously developed has a user-friendly test procedure with excellent sensitivity (100%) and specificity (100%) and reliability in test results.

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