How early you are able to take a pregnancy test will depend on the type of test that you use. All pregnancy tests measure the amount of the pregnancy hormone, human chorionic gonadotrophin (hCG) in your body. This hormone is produced when the egg is fertilized and attaches to the uterine wall, usually six days after fertilization.
Some tests are more sensitive than others and can detect very low levels of hCG in your body. The more sensitive tests could detect hCG as early as four days before your missed period. The sensitivity of a pregnancy test can be found on the packaging and is measured in mIU/ml (milli-International Unit per milliliter). Sensitivity can range from 10mIU/ml to 40mIU/ml. The lower the number, the more sensitive the test is and, in turn, will detect pregnancy sooner.
Different Types of Tests
There are two main types of pregnancy tests, urine test and blood test. Both tests detect the amount of hCG in the body.
Urine tests can be purchased at the grocery store or pharmacy and done in the privacy of your home. Results are most accurate when the test is performed when your period is due, or about 2 weeks after you ovulate. However, some can detect pregnancy as early as 4 days before your missed period.
If you get a positive result, you will want to make an appointment with your doctor to have a blood test done to confirm the pregnancy and begin prenatal care.
If you get a negative result, you either may not be pregnant, or may have ovulated later than you expected and levels of hCG may be too low to be detected. If you still do not get your period, test again in a few days. The levels of hCG will continue to increase rapidly, practically doubling every two to three days, and may be high enough to then be detected by the test.
Blood tests are done at a doctor’s office or lab and are also effective in detecting hCG in the body. Blood tests are more sensitive than urine tests and can detect pregnancy as early as 6-8 days after ovulation. Unfortunately, most doctors will not perform the blood test until after the date that your period is due has past. The results of blood tests also take longer than a urine test.