Increased levels of hCG are due to pregnancy. HCG levels of 0-5 means no pregnancy. After 4 weeks of last menstruation or 2 weeks after conception, hCG levels can be up to 426. After the 3 weeks of last menstruation or one week after the conception, hCG levels are not detectable and can not confirm pregnancy. In my opinion, your levels of 270 are after 4 weeks of pregnancy. Your doctors can be right if they are taking your pregnancy from day of conception.