What immunoassay interferences are commonly due to heterophile antibodies and how can they be mitigated?

• A. Heterophile antibodies can cause falsely high or low immunoassay results; mitigated by different assay formats, alternative antibodies, or specimen dilution.
• B. Heterophile antibodies can cause falsely high or low immunoassay results; mitigated by adjusting sample volume.
• C. Heterophile antibodies improve assay specificity.
• D. Heterophile antibodies have no effect on immunoassays.

Answer: (A)

Heterophile antibodies can interfere with immunoassays by bridging the capture and detection antibodies or by blocking binding, which can create a signal even when the analyte is absent or mask a true signal. This interference can cause results that are falsely high or falsely low, and the effect depends on the specific assay format and reagents used.

The best way to mitigate this interference is to modify the testing approach in ways that reduce or eliminate the bridging or blocking. Using a different assay format, switching to antibodies from different species, or employing alternative antibodies can prevent the heterophile antibodies from forming the non-specific bridge. Pre-treating or diluting the specimen can also diminish the interfering activity and reveal whether the signal is due to true analyte presence or to interference. These strategies address the root cause by changing how the assay components interact with potential heterophile antibodies, making the test more reliable.

Other options like adjusting sample volume are not standard, and heterophile antibodies do not improve specificity nor have no effect on immunoassays; their impact is to distort results unless mitigated.