Every woman who is trying to conceive has wondered how soon can she detect that pregnancy has occurred and which methods are most reliable. Various pregnancy tests can be found on the market claiming to detect pregnancy as early as 2, 4 or even 6 days before expected period. Testing before period absence is often unreliable because if ovulation hasn’t been tracked by one of available and valid methods, it is difficult to know how much has passed since ovulation and in case of negative test pregnancy can’t be eliminated. If ovulation day is known pregnancy tests of 25 mIU/mL of β-hCG can give reliable results as early as 10. days post ovulation (DPO). In case of inconclusive results, test should be repeated after 48 hours since in that period β-hCG concentration will double in serum and also in urine and test will give clearer results.