HIGH DOSE HOOK EFFECT IN THYROGLOBULIN ASSAY: CASE STUDY

*Dr. Jayesh Warade and Dr. Hari Shankar

ABSTRACT

The hook effect is common phenomenon in day-to-day work of a clinical laboratory and should not be neglected. Commonly followed laboratory methods in our country are immunometric and enzyme-linked immunosorbent assays where the prevalence of hook effect is more. In spite of huge prevalence of hook effect it is not well documented in most of the laboratory set ups. With the introduction of newer assay techniques like chemiluminescence, high-dose hook effect has only occasionally been observed. The thyroglobulin value for the patient who was known case of follicular carcinoma of the thyroid was obtained as 0.0 ng/ml during initial testing. Suspecting the false negativity the sample was processed in serial dilutions. Final value was obtained in 500 dilution as 64849.3 ng/ml.

Keywords: Hook effect, Thyroglobulin, immunometric, antigen-antibody.