- Providing a superb example of the ever-changing biomedical landscape for even the most mundane of diagnostics, researchers at Washington University School of Medicine find that some commonly-used urine pregnancy tests lose their negative predictive values after five to seven weeks due to the interference of a variant of the pregnancy hormone human gonadotropin ((hCG)).
- A false negative result poses risks to pregnant women who may undergo x-rays, take certain contraindicated medications or have ectopic pregnancies.
- Easy-to-use visually-interpreted pregnancy tests have been used by women and clinicians alike for decades. All hospitals offer them.
- Two tests, Genzyme's (SNY) OSOM and Cen-Med's Elite were so inhibited that they pose an unacceptable risk of false negatives.
- The researchers suggest that manufacturers revise their products' labeling while they refine their tests to account for the interference.
- Only urine samples present the risk because the hCG variant is not present in serum.