Taking Pregnancy Test. False Positives, Negatives
First Morning Urine, or any time of day?
First morning urine (FMU) generally contains the highest concentration of HCG, and is often recommend by HPT manufacturers, particularly if you are testing early, meaning before your expected period.
If you are not testing early, you can test at a later time in the day -- if the manufacturer's test instructions indicate this is acceptable. However, to avoid diluting HCG in your urine, you should not drink large quantities of liquid an hour or two before you take the test.
Factors Effecting HPT Results
Some fertility medications contain hCG, such as Pregnyl® and Profasi®. Testing too soon after taking these drugs can result in false positives (the test shows you are pregnant, when you are not: instead, the test actually showed positive because of the hCG in the drug).
If you have been pregnant recently, even if you miscarried, your urine may contain hCG based on that pregnancy. As a result, the test may how a false positive, even though you are not actually pregnant now.
A false negative (the pregnancy test shows you are not pregnant, when in fact you are) is more common than a false positive, and can occur for several reasons, including you tested too early. My home pregnancy test is negative- when should I test again?
*Pregnyl is a registered trademark of Organon USA, Inc.; Profasi is a registered trademark of Ares Trading S.A.