What corrective action should be taken when an indeterminate pattern occurs in an indirect IFA?

An indeterminate pattern in an indirect immunofluorescence assay (IFA) often indicates that the initial test results are not definitive, which could suggest a low antibody titer or the presence of non-specific binding. Diluting the sample and retesting is the appropriate corrective action in such cases. By diluting the sample, you can reduce potential interference from high levels of background fluorescence or non-specific binding, thereby enhancing the likelihood of obtaining a clearer result that reflects the true presence of antibodies.

This approach allows for better interpretation of the test by potentially identifying specific reactivity patterns that could be masked at higher concentrations. Additionally, repeating the test under these circumstances can be essential for confirming the presence or absence of antibodies, as it can minimize variability and improve accuracy.