Interference of recombinant human interferon α2b in human chorionic gonadotropin assays: a case report and clinical analysis.

Background: Recombinant human interferon α2b (rhIFN-α2b) is a widely used antiviral and immune-modulating agent. However, its potential to interfere with immunoassays, particularly human chorionic gonadotropin (hCG) tests, has not been extensively documented. This case report highlights the challenges of interpreting hCG assay results in the context of rhIFN-α2b therapy. Case Description: A 24-year-old female presented with amenorrhea for over 40 days, and tested positive for urine hCG using the colloidal gold method (124 IU/L). However, her serum β-hCG measured by electrochemiluminescence was <0.200 IU/L, and her progesterone was 29.3 nmol/L. A further analysis across platforms revealed that the Roche, Beckman, and Mindray chemiluminescence methods were unaffected by rhIFN-α2b, while the colloidal gold urine hCG, quantitative immunochromatography, and Abbott chemiluminescence assays were affected by rhIFN-α2b. This interference likely stems from the immunomodulatory effects of rhIFN-α2b, which can cause non-specific binding to assay antibodies. Conclusions: This case underscores the importance of using multiple testing platforms and conducting thorough clinical assessments to avoid false-positive results. It also highlights the need for assay developers to consider epitope targeting in reagent design to minimize interference. Clinicians and laboratory professionals should be aware of the potential for rhIFN-α2b to cause assay interference and collaborate closely to ensure accurate interpretation of test results. This case calls for further research into the prevalence of rhIFN-α2b-induced hCG assay interference and the development of strategies to mitigate its impact on clinical diagnostics.