Understanding Home Pregnancy Test Accuracy

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Millions of women use home pregnancy tests to detect small levels of human chorionic gonadotropin (hCG), also known as the pregnancy hormone. Can you rely on home pregnancy test accuracy to tell you when you’re pregnant? Here’s a quick look at how accurate these tests really are and how you can improve their reliability.

Home Pregnancy Test Accuracy
Most home pregnancy tests claim to be 97 to 99% accurate on the date you miss your period. A few studies have found that these at-home tests are not very consistent in their ability to detect pregnancy this early, however. The accuracy of home pregnancy tests increases dramatically when the package directions are followed 7 days after a missed period. There are 4 main things that affect the accuracy of your home pregnancy test:

1. How they are used. Make sure the test is not expired and follow all included directions. The instructions will give you a window for valid results, so checking the test results too soon or too late may result in a false positive or negative. Some research shows that these tests are most accurate 10 minutes after you perform the test.
2. When you use it. The level of hCG in your urine increases rapidly as your pregnancy progresses. The sooner the test is taken after a missed period, the harder it is to detect hCG in your urine. While some tests claim 99% accuracy on the day of your missed period, it’s actually hard to detect low levels of hCG at this time. Waiting one week after your missed period will give you more accuracy.
3. Who uses it. Every woman ovulates at a unique time in her cycle, and the fertilized egg can implant into the uterine wall at different times. Because hCG is only released when the egg implants, your test may not detect anything the day of your missed period. Around 10% of women don’t experience implantation until after the day the miss their period, so accuracy can depend on the individual, as well as timing.
4. The brand of the test. Some home pregnancy tests are more accurate than others and able to detect smaller amounts of hCG.

How to Improve Home Pregnancy Test Accuracy

• Use the first morning urine, which is more concentrated and contains higher levels of hCG, if present. If you don’t use the first urine of the morning, make sure you at least wait 4 hours after peeing to take the test and don’t load up on fluids.
• Don’t drink a lot of fluids to increase the volume of urine you produce. This will dilute the urine and make it more difficult to detect the hCG hormone.
• Certain medications, especially fertility drugs, can affect the results of an at home pregnancy test.
• Wait 7 days after the day of your missed period to take the test. Some tests are more accurate than others, but it’s still very hard to detect hCG levels very early in your pregnancy.