Most home pregnancy test these days have very high accuracy usually quoted at around 98-99% accuracy, if, and this is the important bit, used according to manufacturers instructions.
What does this actuually mean ?
The quoted accuracy figures refer to clinical trials and the rate of pick up of pregnancy in pregnant womens urine, in which the level of pregnancy hormone in the urine sample is greater than the detection level of the test and where the test is being performed by someone who is familiar with the testing process. Quite often the test is being performed in a lab.
This does not mean that if you use the test it will have a 99% chance of detecting pregnancy every time. If the pregnancy is very early the pregnancy hormone (Hcg) may not be sufficiently high to give a positve result on the pregnancy test that you are using. This can cause confusion as many women are now testing for pregnancy before the missed period when the hcg levels are still very low.
Factors that affect the accuracy of the home pregnancy test:
- whether the pregnancy test is performed correctly-make sure you read and follow the instructions that the manufacturer has provided. Not all pregnancy tests are the same and user error is common if you are not familiar with that particular brand of pregnancy test.
- how concentrated is the urine sample-it is always best to do a pregnancy test on the urine that you product first thing in the morning on rising from bed, as this is the most concentrated. Often refeered to by doctors as the ‘1st morning void’
- What is the sensitivity of the home pregnancy test that you are using ? The lower the mIU detection level of the pregnancy test the more sensitive is the pregnancy test ie a 10mIU pregnancy test will detect pregnancy earlier than a 25mIU pregnancy test. Some brands of pregnancy test do not disclose the detection level of the test-in this case look for a pregnancy test that says very early detection or ultra early detection if you are testing before your missed period, as these should be more sensitive than a standard home pregnancy test.
- Make sure that you time the pregnancy test and read the result at the correct time-this varies from brand to brand so it is important to read the instructions fully before you start.
If you followed all the instrucions and the result is negative, this does not necessarily mean that you are not pregnant. It may just mean that the pregnancy hormones have not reached a sufficiently high level to give a positive pregnancy test on the particular brand of pregnancy test that you are using. If this is the case and you have not started your period then wait 48 hours (if you can ) and do another pregnancy test on a 1st morning void.
Hope this information is helpful to you. Any questions or comments e-mail us or post in comments