Which statement correctly matches the anticoagulant and its typical use in common plasma tubes?

• A. Lithium Heparin in Green Tubes Used for Coagulation Studies.
• B. Sodium Fluoride/Potassium Oxalate in Gray Tubes Used for Glucose Testing.
• C. Citrate in Light-Blue Tubes Used for CBC Testing.
• D. EDTA in Lavender Tubes Used for Chemistry.

Answer: (B)

Understanding how anticoagulants and additives suit specific tests helps you pick the right tube. The gray top tube uses potassium oxalate as the anticoagulant to prevent clotting and sodium fluoride as a glycolysis inhibitor to stop glucose from being consumed by cells. This combination specifically preserves glucose levels in plasma, making it the appropriate choice for glucose testing.

In contrast, lithium heparin on green tubes is mainly used for plasma determinations in chemistry, not for coagulation studies; citrate in light-blue tubes is the standard anticoagulant for coagulation testing (not CBC); and EDTA in lavender tubes is used for hematology/CBC because it preserves cells well, not for routine chemistry.