Which anticoagulant is recommended for preserving blood samples for toxicological analysis?

• A. Sodium citrate
• B. EDTA
• C. Sodium fluoride
• D. Heparin

Answer: (C)

Sodium fluoride is recommended for preserving blood samples for toxicological analysis primarily because it acts as a glycolytic inhibitor. This means it prevents the metabolism of glucose by erythrocytes (red blood cells), thereby maintaining the integrity of the sample. In forensic toxicology, it is critical to prevent any biological processes that could alter the concentration of drugs or other substances present in the sample, which sodium fluoride effectively achieves.

Additionally, sodium fluoride can also inhibit the activity of certain enzymes that might degrade the sample or interfere with subsequent analyses. This characteristic makes it an ideal anticoagulant for toxicological studies where accurate measurement of substances in the body is crucial.

Sodium citrate, EDTA, and heparin, while effective anticoagulants in various contexts, do not provide the same level of metabolic inhibition that sodium fluoride does. Therefore, they are less suitable for preserving blood samples specifically for toxicological analysis, where maintaining the original state of the sample is paramount.