a blood test will detect pregnancy if that is what the doctor is looking for. you would have to tell them, they dont just test for pregnancy in a routine blood test.
unless that's what they're looking for...no. they don't just randomly test for pregnancy. if you want to know if you are pregnant either take an hpt or tell the doc.
if is regular bloodwork no. you will have to ask him to do it. is called a beta hcg.