Burglar breaks in and steals a ton of golf clubs, but leaves blood on the broken window. Local security see him exit and chases him around the neighborhood until the SO officers can arrive to arrest him.

Evidence is pretty stubstantial against the defendant: Eye witness, Property found in his possession.. etc.

The investigator wants to test the blood to be sure, and asks: do we need to get a search warrant for the defendant's DNA if he refuses to consent to give a sample?

I immediately thought, well yes. But quickly realized I didn't know. I think I'm just spooking at the fact that it's 'DNA' evidence. Are there specific statutes covering this sort of specific scientific evidence?

I'm spooked because: There was an article a few months ago about officers that were collecting DNA samples of all of the black males on a college campus, essentially doing a dragnet looking for a serial rapist. (questions of racial profiling and such arose) It seemed that they had some special right to simply swab up the students that fit the description.

Yes, you will need a search warrant to draw blood. Blumenstetter v. State, 135 S.W.3d 234, 242-43 (Tex.App.-Texarkana 2004, no pet. h.) (PC & exigent circumstances needed for no consent warrantless search). I guess if the guy is in custody -- and you have enough zeal -- you could get some kind of effluent from him without a warrant that would contained DNA

My dictionary says effluent is the outflow from a sewer or septic tank.

Stealing golf clubs?

That oughta be a hangin' offense ...