How Do Pregnancy Tests Work?
Pregnancy tests determine pregnancy by detecting a hormone called human chorionic gonadotropin (hCG) in a woman’s blood or urine. HCG is typically only detectable in the body during pregnancy. During early pregnancy, the embryo’s placenta begins to form and produce hCG and then builds to a detectable level as the pregnancy develops.
Blood and urine tests both detect hCG in a woman’s body. Blood pregnancy tests can detect a lower level of hCG than urine tests. Blood tests are available at medical offices, but they may take hours or up to a full day to return results. They are also more expensive, so many providers use urine tests instead.
A healthcare provider may order blood hCG testing to monitor the hCG level to ensure it is adequately rising to support a pregnancy.
Urine tests are readily available for consumer purchase. Over-the-counter tests range in accuracy, with some claiming to be accurate up to 10 days before a missed period. Still, some women find the directions confusing and often take multiple tests because they doubt the reliability of the test.
While false responses are uncommon, user error can cause an inaccurate reading. For example:
- Testing too early can cause a false negative.
- Testing at the wrong time of day can result in a false negative if the urine isn’t concentrated enough.
- Evaporation lines that look like a positive response can appear if too much urine is applied to the test strip or if you read the test results after the indicated time.
Free Pregnancy Testing
At Your Options Medical, you can rely on our professional nurses to correctly administer a lab-quality pregnancy test as early as 7-10 days after you have had sex. With a positive test, you will be offered a free ultrasound to confirm the pregnancy, so you aren’t left wondering. Schedule your free pregnancy testing appointment today.