Originally Published IVD Technology
March 2003
INDUSTRY NEWS
Consumer Reports rates pregnancy test kits |
Most pregnancy test kits claim 99% accuracy, yet a new study by Consumer’s Union reveals that all kits are not created equally. This study, presented in an article titled “When the Test Really Counts” in the February 2003 issue of Consumer Reports (CR), was a consumer-oriented study of 18 pregnancy test kits. The study concluded that the First Response Early Result Pregnancy Test substantially outperformed the others in terms of both reliability and sensitivity. Both this kit and the Clear Choice At Home Pregnancy Test detected levels of human chorionic gonadotropin (hCG), a hormone released by the developing placenta when it implants itself in the uterine wall, at concentrations as low as 6.5 mIU/ml. The most sensitive of the remaining 16 tests was not able to detect hCG in urine until it reached a concentration of 100
mIU/ml.
CR describes many of the claims on the labels made by kit manufacturers as “untrustworthy.” Several test kits were less accurate at the manufacturer’s suggested reading time of 1 to 3 minutes than when read at the 10-minute maximum. Additionally, although many tests claim to be accurate when conducted the day after a period has been missed, those results can be misleading, whereas a test taken one week later will most likely be accurate.
Sensitivity, waiting time to receive results, and readability were deemed to be among the most important criteria for consumers.
An earlier study published in the December 2001 issue of Clinical Chemistry compared the efficacy of 15 pregnancy test kits and revealed that a different set of criteria was deemed important to the diagnostic industry. The study compared sensitivity to both hCG and H-hCG, a large hCG variant that is also the principal hCG-related molecule in pregnancy urine during the first two weeks following pregnancy. The researchers found that 60% of the tests had poorer detection limits for H-hCG than for hCG.
No investigation was made of the optimum amount of time required to receive accurate test results, the best time of the menstrual cycle for conducting the test, or the readability of the result. However, all of these criteria affect the accuracy of test results and appear to be of strong importance to the consumer.
A third set of criteria was used by a medical industry-oriented study of pregnancy test kits published in the September/October 1998 issue of the Archives of Family Medicine. That study compared the accuracy of test results obtained by investigators from patients’ samples, volunteers from patients’ samples, and those gathered by patients from their own samples. This study determined that the diagnostic efficacy of home pregnancy test kits is greatly affected by the individual characteristics of users, pointing to a need for more-extensive and uniform public education about how to perform the tests.
The variety of criteria used in these three studies points to the need for a collaboration and open dialogue between the IVD industry, practitioners, and the device-user population when designing a point-of-care device development plan.
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