Pregnancy test accuracy
Each type of pregnancy test is designed to detect a set minimum level of hCG. This is why pregnancy test manufacturers advertise the way they do: “Know four days sooner,” or “Accurate up to six days before a missed period.” However, while home pregnancy tests are quite accurate – many boast a 99% detection rate based on laboratory testing results – marketing claims can be misleading.
For example, a 99% detection rate means a test can detect hCG 99% of the time on the day you miss your period. These statistics also assume that women are testing at the optimal time and following all instructions correctly.
Many home pregnancy tests available today are midstream urine dip tests, which are the traditional “pee-on-a-stick” tests and are fairly easy to use. There also are tests in which you pee into a cup and dip a test strip into the urine. The New York Times published a story ranking the best home pregnancy tests, citing a midstream test with an ergonomic grip as the easiest to use and most accurate.
Research has shown that average test results when women used the dip tests matched lab test results just 70% of the time, whereas 99% of women typically can get an accurate reading from a midstream test.