What additive do light blue topped tubes hold?

What additive do light blue topped tubes hold?

• A. Sodium Citrate
• B. EDTA
• C. Heparin
• D. Oxalate

Answer: (A)

For coagulation testing you need an anticoagulant that stops clotting without destroying the clotting factors, and it must preserve the plasma. Light blue topped tubes use sodium citrate to achieve this. Sodium citrate binds calcium in the blood, temporarily preventing clot formation so the plasma can be separated and tested for clotting times like PT and APTT (and INR). Getting the volume right is crucial because the citrate-to-blood ratio (about 1 part citrate to 9 parts blood) must be maintained; underfilling alters this ratio and can skew results. Other tube additives serve different purposes and colors: EDTA is for CBCs, heparin is for certain chemistry tests, and oxalate (often with fluoride) is used for glucose testing, not coagulation studies. So, the additive in light blue tubes is sodium citrate.

For coagulation testing you need an anticoagulant that stops clotting without destroying the clotting factors, and it must preserve the plasma. Light blue topped tubes use sodium citrate to achieve this. Sodium citrate binds calcium in the blood, temporarily preventing clot formation so the plasma can be separated and tested for clotting times like PT and APTT (and INR). Getting the volume right is crucial because the citrate-to-blood ratio (about 1 part citrate to 9 parts blood) must be maintained; underfilling alters this ratio and can skew results. Other tube additives serve different purposes and colors: EDTA is for CBCs, heparin is for certain chemistry tests, and oxalate (often with fluoride) is used for glucose testing, not coagulation studies. So, the additive in light blue tubes is sodium citrate.