Hook effect in Abbott i-STAT β-human chorionic gonadotropin (β-hCG) point of care assay.

Unlabelled: Point-of-care testing for β-hCG has been widely advocated to allow rapid diagnosis/exclusion of pregnancy in the emergency department. A quantitative blood β-hCG assay has the additional benefit of being able to monitor the viability of pregnancy, using serial measurements, to determine the appropriate expected increase in β-hCG levels over time (e.g.