Depending on how the blood dries, clumps or spreads, you will be able to compare your blood stain to a results card. Within minutes, you'll be able to determine your blood type. At-Home Blood ...

and of what appeared to be a large blood stain on the underside of the mattress. Jane Dorotik: I do know when Bob had a nosebleed he made a comment about getting some blood on the mattress.