when should hcg blood test be done
More sensitive tests, those that are able to detect a lower amount of hCG, can provide an accurate result as early as 7-10 days post ovulation. When deciding if you should use an HPT or have a blood pregnancy test done at the lab, here are a few items to consider: (See the chart below for average blood hCG levels as pregnancy advances). 2  If hCG levels do not rise appropriately in those very early days, it can signal a problem with the pregnancy. 3  By monitoring your exact hCG levels with regular quantitative blood test, your doctor may be able to detect a problem early on.