wht can't blood be collected in tubes containing fluoride as preservative and anticoaugulant?

Answer 1

There is a certain tube that has sodium fluoride compound in it. That simply means there is a fluoride in it.

The tube contains potassium oxalate as an anticoagulant and sodium fluoride as a preservative - used to preserve glucose in whole blood and plasma analyses for acetone, and alcohols.

Every different tubes have other specific preservative and anticoagulants to keep the the particular blood components unaltered thus obtaining accurate results.

Answer 2

You are referring to the "gray tops" that contain fluoride and oxalate. The fluoride is not a preservative relative to microbes. It inactivates enzymes that digest glucose in the sample. The oxalate is the anticoagulant. These will interfere with a number of assays. Because of the anticoagulant, no assay can be run where the anticoagulation will reverse and a clot will foul the assay. The fluoride may be misinterpreted in other assays, or may inactivate the enzymes used to make such assessments.

Answer 3

Flouride helps tooth enamel and is safe if ingested. I doubt it's as safe in the bloodstream (not really sure,) and it's not a preservative in the sense of extending efficacy or shelf life.