How Early to Test for Pregnancy

Patient: Sorry for the long details… I am a 33 yr old female who has always been very regular with my menstrual cycle (7 days). Not sure if I might be pregnant. My last menstrual cycle was on Aug. 23, 2009. Did engage in unprotected sex on Sept. 13, 2009. My next menstrual cycle was due on or around Sept. 20, 2009. Not sure if what I got was my period. Started on Sept. 20 with not much happening on that day very light spotting in the morning with a normal flow late in the evening. The following day was a normal flow compared to a heavy flow that I always get, after that evening there was very light spotting for the next 2 days followed by nothing for the next 4 days. The week after this I started feeling period like cramping, headaches, nausea (very light) and loose stool. Took a home pregnancy on the week that I was suppose to be on my period (9/24/2009) came out negative.  I did experience implantation bleeding for the 1st 3 months of my 1st pregnancy 14 yrs ago. Could I be pregnant? When is the best time to retest?

Doctor: Pregnancy can occur anytime there is unprotected sex.  Fortunately, even though it can be difficult for you to tell earl ly on, it is easy for your doctor to diagnose.It is diagnosed by detecting the presence of a hormone, HCG, which is produced by the placenta.Home pregnancy tests are quite accurate as they qualitatively test for HCG hormone.  This means they test for the presence of HCG hormone and not the amount.  Its basically a simple “yes its there” or “no its not” test.  The best home pregancy tests on the market can give you an accurante response as early as 7 days after conception .A blood test performed by your doctor  is a quantitative test for HCG hormone.  This means that not only is the test able to detect the presence of HCG hormone, it is able to also tell you how much.  The amount of hormone can be an indication of how far along the pregnancy is.  The blood tests can be very accurate even earlier than urine tests.If you are concerned about pregnancy, I suggest you visit your doctor for a simple blood test.  I have seen cases where the store bought test was negative and the blood test was positive.