CAPTURE ELISA - Improvement in specificity and sensitivity for IgM detection


PROBLEM :

    In India, there is a high prevalence of IgG antibodies in Infectious diseases. Thus if high affinity antibodies to the specific antigen is present in the sample then, it may preferentially bind to the antigen. This may interfere with the detection of antigen specific IgM antibodies. This may lead to false negative or even false low positive IgM results. Also Rheumatoid factor (RF) has very high prevalence in India which are antibodies directed to the Fc region of IgG, IgM and IgA type antibodies, are produced during Rheumatoid arthritis. Presence of IgG RF may also lead to a false positive IgM results.
SOLUTION :

    In u CAPTURE ELISA, the microtitre plates are coated with anti IgM antibodies. This step helps in binding of only IgM antibodies in first step and removes all IgG in first step washing and eliminating any chances of IgG cross reactivity in IgM tests. During the second step specific antigen bound to the enzyme conjgateis added. This, then acts on the appropriate substrate to give a colored product which can estimated calometrically to estimate the antigen specific IgM type of ntybodies in the serum sample. This step eliminates the interference caused due to IgG RF.

Special features of ToRCH IgM ELISA :

  • Based on Mu-capture ELISA for better sensitivity & specificity
  • This capture technique eliminates the competition between IgG & IgM antibodies.
  • No interference caused due to rheumatoid factors.
  • No preabsorption of the serum required.
  • 96 break away microwells format.
  • Sample volume required : 10ul
  • Simple & same procedure for all IgM kits, making it adaptable to any instrument.
  • All the three controls (positive, negative & cut-off controls),sample diluents are ready to use.
  • Following reagents are interchangeable between lots such as negative control, wash buffer, sample diluents, substrate and stop solution.
  • Same sample diluent: removes the need for multiple dilutions for the same sample.
  • CE marked kits.