Home Pregnancy Tests(HPTs) Accuracy, Sensitivity
Testing at Home for hCG Levels; Pregnant Positive Results
Nov 3, 2009
HPTs are found in every drugstore, are easy to use, relatively inexpensive, and very sensitive, showing accurate positive levels of beta hCG, the hormone measured by the tests, very early in pregnancy, often before the first missed period.
Accuracy of Home Pregnancy Tests for Beta hCG Levels
Human chorionic gonadotropin, or hCG, is a hormone released by the growing placenta after an embryo implants. Women generally start their periods 14 days after ovulation. HCG levels in early pregnancy rise like this, on average:
- 10 days after ovulation: beta hCG level 25mIU/ml
- 12 days after ovulation: beta hCG level 50mIU/ml
- 14 days after ovulation: beta hCG level 100 mIU/ml
Virtually every early detection pregnancy test has the sensitivity to detect 100 mIU/ml of hCG, so a test will be positive by the first missed period in most cases. Most HPTs have two lines, one for a “control” and one that shows the actual result. The actual result line should be darker than the control line in a positive pregnancy test. Results show up in just a minute or two.
Pregnancy Test Sensitivity by Brand
Most pregnancy test kits today have similar sensitivity levels. Nearly every test registers positive between 25-50 MIU/ml and should be accurate by the first day of a missed period. It doesn’t matter which test is used; the cheaper tests are also accurate. Buying tests in bulk may save money for compulsive testers.
Using Home Pregnancy Test Kits Correctly
To get the best results from HPTs:
- Test first thing in the morning, because the urine in the morning is most concentrated, and will give the most accurate results
- Read the tests within the time stated on the HPT. The test band may change colors and not be accurate if it isn’t read within the allotted time.
False Positives and Negatives on Home Pregnancy Tests
Everyone is different, and hCG levels aren’t exact from one women to another. A negative pregnancy test, especially if done right before or the day of a missed period, may still be positive; it might just be slightly too early. Test again in a few days (okay, a few hours), and be sure to use the first urine sample of the day.
False positives are far less common, except for the following conditions:
- Taking hCG injections for an IVF or IUI cycle ; hCG in small amounts may still be present in the urine up to 14 days, although it usually clears by day 10 after the injection.
- Miscarriage in the past month; it takes four weeks or so for the hCG levels to drop completely.
Early Detection Pregnancy Kits Are Convenient and Accurate
It’s easy, effective and reasonably inexpensive to do urine pregnancy tests at home. Women today want to know if they’re pregnant as early as possible, and the accuracy of home pregnancy test kits makes it possible—and fun!
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