Which tube is associated with the orange lid containing lithium heparin for biochemistry testing?

• A. EDTA blood tube
• B. Lithium heparin blood tube
• C. Sodium fluoride and potassium oxalate blood tube
• D. Heparinized saline

Answer: (B)

Biochemistry panels need plasma that is free of clots and not distorted by additives. Lithium heparin acts as an anticoagulant that prevents clotting while preserving analytes for most chemistry measurements, making it a practical choice for biochemistry tests. The orange-lid tube is the one labeled for this lithium heparin additive, which is why it’s associated with chemistry work.

EDTA would distort many chemistry results because it binds calcium and other ions, so it’s kept for hematology. The sodium fluoride and potassium oxalate (gray) tube is mainly for glucose testing due to glycolysis inhibition. Heparinized saline isn’t used as a routine blood collection tube for chemistry panels; it’s used to flush lines or for specific short-term sample handling.