There are 2 main types of pregnancy tests, a urine test kit which can be performed in the convenience and privacy of your own home or in the clinic, and a blood test that must be performed in the clinic.
Both tests work by measuring if there is a hormone called Human Chorionic Gonadotrophin (hCG) which is produced after a fertilised egg is attached to the womb.
The urine test kit is what I would call a “qualitative” test kit, it gives you a “Yes” or “No” answer and it works once the hCG reaches a certain level. The test kits available in the pharmacies are generally quite accurate and would be sensitive enough to pick up a pregnancy if you missed your menses by a week and suspect you may be pregnant.
The blood test is a “quantitative” test kit and it measures the amount of hCG in the blood. A level of more than 25 mIU/ml is considered positive for pregnancy. It is, therefore, more sensitive in a way and can pick up pregnancies even earlier. As such, I use this test if my patient is very anxious and wants to pick up the pregnancy earlier or if my patient has an irregular menstrual history and does not know if she has missed her menses.