Pregnacy test results

HCG is human chorionic gonadotropin. It is a hormone produced by the placenta during pregnancy. Home pregnancy tests (HPTs) are designed to detect it.

HCG is detectable in the blood serum of approximately 5% of pregnant women by 8 days after conception, and in virtually all the rest by 11 days. HCG rises progressively from conception. Levels double on the average, every 30.9 hours until values reach 6500 mIU/ml (6,500 IU/L) at approximately the eighth week after the last menstrual period (LMP). After that the rate of rise becomes individualized, peaking between the 60th and 70th day (9 to 10 weeks) LMP. HCG decreases slightly between the 12th and 16th week post LMP, and then remains constant until birth.

A blood serum level of less than 5 mIU/ml (5 IU/L) can be considered negative and anything above 25 mIU/ml (25 IU/L) positive for pregnancy. If you are unsure, repeat the test in two days to see if there is an upward trend, which indicates pregnancy.

Endometriosis and fertility drugs can cause false POSITIVE results, not negative. It may be that you have tested to soon, wait until the first day of a missed periode. The tests that claim to be accurate 5 - 7 days before a missed period are only accurate at that early stage in about 17% of pregnancy, the tests accuracy percentage raises the closer you get to your normal periode time, to 99.9% at one day before.

This site may help you sort through home pregnancy test info. You may also want to see your doctor to have a quantative Hcg level taken.

http://www.fertilityplus.org/faq/hpt.html