"Hook-Like Effect" Causes False-negative Point-of-Care Urine Pregnancy Testing in Emergency Patients

Richard T. Griffey, MD, MPH; Caleb J. Trent, MD; Rebecca A. Bavolek, MD; Jacob B. Keeperman, MD; Christopher Sampson, MD; Robert F. Poirier, MD


J Emerg Med. 2013;44(1):155-160. 

In This Article


Urine hCG POC tests generally perform very well, with low false-negative rates. Because POC uhCG tests are optimized for detection of very early pregnancy, when hCG-βcf is not present or is present in low concentrations, antibodies to this variant may not be included in test kits. Manufacturers should consider that their POC uhCG tests are routinely used in emergent settings at many stages of pregnancy. Manufacturers should characterize the hCG variants recognized by their tests, optimize their tests to detect both early and mid-stage pregnancy, and institute quality assurance measures eliminating lot-to-lot variability. Clinicians must familiarize themselves with the mechanisms and limitations of the specific type of urine point-of-care used in their practice while recognizing that under certain circumstances, false-negative tests can occur.[8,14]