I am going to be a nurse and have ran in to a discussion about this last week--So my answer is accurate.
You are way more likely to get false negatives than a false positives. Pregnancy test claim to be 99 percent accurate. False positive pregnancy tests are rare – though there are instances and conditions where they can occur. First of all Chemical Pregnancy (which is an early miscarriage), Also Missed Reaction Time (which is when you let the test sit longer than the alloted time on the box), Evaporation Lines (which is a faint line second line).
Here are some drugs that can cause false positives.
HCG (treatments given to people TTC, and trying to lose weight)
Phenothiazines and phenothiazine derivatives
Phenergan (Nassau medication)
A blood test is very accurate, however, So you should make an appointment to get an accurate answ
at 11:58 AM on Feb. 15, 2011