Home pregnancy tests (HPTs) can be quite accurate. But the accuracy depends on many things. These include:
- How you use them – Be sure to follow the directions and check the expiration date.
- When you use them – The amount of hCG or pregnancy hormone in your urine increases with time. So, the earlier after a missed period you take the test the harder it is to spot the hCG. If you wait one week after a missed period to test, you are more apt to have an accurate result. Also, testing your urine first thing in the morning may boost the accuracy.
- Who uses them – The amount of hCG in the urine is different for every pregnant woman. So, some women will have accurate results on the day of the missed period while others will need to wait longer.
- The brand of test – Some home pregnancy tests are more sensitive than others. So, some tests are better than others at spotting hCG early on.
Many HPTs claim to be 99% accurate on the day you miss your period. But research suggests that most HPTs do not consistently spot pregnancy that early. And when they do, the results are often very faint.
In a 2004 study, researchers tested the accuracy of 18 HPTs sold in retail stores. They found that only one brand consistently detected the low levels of hCG usually present on the first day of the missed period. This was the First Response, Early Result Pregnancy Test. The other tests missed up to 85% of pregnancies on the first day of the missed period. Most tests accurately confirmed pregnancies one week after the missed period.