What additive is present in trace element free blood collection tubes?

What additive is present in trace element free blood collection tubes?

• A. EDTA
• B. Sodium fluoride
• C. Clot activator
• D. Citrate

Answer: (C)

For trace element testing, you want a tube that won’t introduce metals or chelate them, and you need serum rather than plasma. That means the tube should promote clotting without adding anticoagulants or reagents that could interfere with metal measurements. A clot activator does exactly this: it speeds up the coagulation process so blood becomes serum, minimizing any additive that could contaminate or alter trace element levels. EDTA, citrate, fluoride, and other anticoagulants would bind or distort metal ions and are avoided in these tubes. Therefore, the additive present is a clot activator.

For trace element testing, you want a tube that won’t introduce metals or chelate them, and you need serum rather than plasma. That means the tube should promote clotting without adding anticoagulants or reagents that could interfere with metal measurements. A clot activator does exactly this: it speeds up the coagulation process so blood becomes serum, minimizing any additive that could contaminate or alter trace element levels. EDTA, citrate, fluoride, and other anticoagulants would bind or distort metal ions and are avoided in these tubes. Therefore, the additive present is a clot activator.