The information on this site is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images, and information, contained on or available through this website is for general information purposes only. The purpose of this is to help with education and create better conversations between patients and their healthcare providers.. The hCG levels should not be used to date a pregnancy since these numbers can vary so widely. There are two common types of hCG tests. A qualitative hCG test detects if hCG is present in the blood. A quantitative hCG test (or beta hCG) measures the amount of hCG actually present in the blood. Guideline to hCG levels during pregnancy. HCG can first be detected in a blood sample about 11 days after conception. Levels of hCG continue to double every 48 to 72 hours. They reach their peak around 8 to 11 weeks after conception. HCG levels then decline and level off, remaining steady for the rest of the pregnancy..