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DEPENDABLE EXCELLENCE IN VECTOR-BORNE DIAGNOSTICS

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Troubleshooting Immunofluorescence Assays

Question: What reaction density (bacteria) constitutes a positive reaction?

Answer:
1. Antigen density in each antigen spot must be compared with the Positive Control reaction. Fluorescent particles may be seen within antigen spots and elsewhere in the open space, yet the true positive reaction much appear in density like the Positive Control, which is the criterion for judging a particular well as positive.
   
   

Questions / Problems

 

  1. Positive Control is negative or very weak.
  2. Antigen or substrate cells smeared or absent from wells before test.
  3. Antigen or substrate cells washed off during the procedure.
  4. Negative Control is positive.
  5. Reactions are stronger on the edges of the well in comparison to the center.