How accurate is a first response pregnancy test?

November 12, 2012

How accurate is a first response pregnancy test?

There are a number of situations whereby a woman may feel the need to take a first response pregnancy test. She may be hoping to conceive and testing to find out if she’s been successful. Alternatively she may firmly not want to be pregnant and therefore taking a test to check at the first opportunity. Additionally there may be women who have missed a period and decide to take a first response pregnancy test for peace of mind.

How do they work?

A first response pregnancy test works by checking for a certain hormone present in the urine. The hormone is called hormone human chorionic gonadotropin (hCG for short) and is not usually found in adults. The hormone is only found in the placenta of a developing embryo. More specifically it is found in the part of the placenta known as the chorionm, which is where the hormones name comes from. If a woman is pregnant, there should be traces of hCG in her urine. The only other potential explanation for this hormone to be in her urine is if she is currently using a fertility drug that is similar or mimics hCG. Based on this system, first response pregnancy tests should be very high.


First response has a website that contains an abundance of information on pregnancy and the test itself. They are marketing two versions of the first response pregnancy test; the first in called Rapid Results and the second is called Early Results. According to First Response the accuracy of the Rapid Results tests is over 95 % whilst the Early Results tests, they claim to be accurate almost 100% of the time. However there are some exceptions. In reference to the Early Results version of the test, the website states that when taking the test 6 days or more before a missed period, the accuracy level falls to 40% and increases as you get closer to the day of the expected period. Additionally, they go on to say that hormone levels can vary from woman to woman and early on in the pregnancy the hCG levels may not be high enough to detect. There can also be some confusion when using pregnancy tests if it is allowed to develop for longer than the manufacturer instructs. There is something that it is known as the evaporation line, which looks the same as a positive result line but occurs after the instructed development time. This can lead women to read a false positive if they do follow the guidelines closely.


The results provided by a first response pregnancy test can make or break a woman’s heart depending on the result she desired. Whilst the tests are highly accurate, there is room for error as the test relies wholly on being able to detect small changes in the levels of hormone present the urine. Also remember that the closer to a missed period and after it, the more accurate the test becomes.


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