Will a blood test say negative if you have an ectopic pregnancy?

Usually not: An ectopic pregnancy with a living conception will produce the same hormones that an intrauterine pregnancy does, and noticing this is part of the diagnosis. If death occurs, the levels will drop off. If an ectopic pregnancy has affected you or a loved one, you have my sympathy -- my hope is you will be able, if you wish, to go on to have a healthy child.