Pregnancy Test Accuracy

There are many characteristics of a good pregnancy test… indeed, entire articles have been written on the subject of what constitutes the “best pregnancy test“. But undoubtedly, the ability of a test to correctly measure what it purports to measure, or in other words, the accuracy of a pregnancy test, is absolutely critical. After all, a pregnancy test can be easy to use and inexpensive, but if it yields inaccurate results, it’s worthless.

Pregnancy test accuracy is typically expressed in terms of percentages. For example, the pregnancy tests sold at have a stated accuracy level that exceeds 99.9%. This means that the pregnancy tests will correctly yield a positive result 99.9% of the time when immersed in a sample containing 20 miu/ml or greater of the hormone Human Chorionic Gonadotropin (hcg). The accuracy of most brands of pregnancy tests, generally speaking, tends to be around the 99% mark.

These tests are calibrated such that a faint test line will be visible at 20 miu/ml hcg, while no test line should be visible at lower levels. This is an important quality of an accurate test, as we all (even men) have baseline levels of hcg in our non-pregnant state, and would not want these baseline hcg levels causing false positive results.

As hcg levels increase beyond the 20 miu/ml threshold for pregnancy detection, the test line will increase in intensity.  See the image below taken by an actual customer for an illustration of this effect.

Pregnancy Test Accuracy

Note that at 11 days past ovulation (DPO), the test line is visible, but just barely. We can assume based on this result that this person’s hcg level at 11 DPO was very close to the 20 miu/ml threshold for yielding a positive result. As time goes by, however, note that the intensity of the test line increases until at 17 days past ovulation, the intensity of the test line is nearly equal to the intensity of the control line.

To read actual customer feedback regarding the accuracy of the pregnancy tests sold at, click the reviews tab of the pregnancy test strip product description.

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