Do pregnancy blood test usually show up neg?
There are 2 types of blood tests to detect if you are pregnant. 1.Quantitative Blood Serum Test it is very accurate and tests the EXACT amount of HCG levels in your blood even trace amounts. This is the one they use when you may be miscarrying because it is easy to watch the numbers increase or decrease over a period of time. 2.Qualitative Blood Serum Test can only confirm whether HCG (the hormone they look for) is in your blood and tends to be as accurate as an HPT. Some medications you take CAN decrease the amount of HCG actually present in your blood. Promethazine which is used as an antihistamine in combination cough and cold products to treat allergy symptoms and to treat nausea or vomiting from illness or motion sickness. Also diuretics taken for fluid retention. http://contraception.about.com/od/contra… Also different labs consider different levels of HCG to indicate pregnancy. HC
