After 2 months of getting false positives on 4 different brands of home pregnancy tests including this brand, I realized that LH would cause false positives . So if you see a line and then do a blood draw and find out you are not pregnant, apart from the fact that it is a chemical (which I did not have), please understand that LH can cause the line to form , and some women take in enough LH at the end of their cycle to get a false positive result.