Hypocalcemia during blood transfusion is primarily caused by what substance in stored blood?

Hypocalcemia during blood transfusion is primarily caused by what substance in stored blood?

• A. Citrate
• B. Magnesium
• C. Potassium
• D. Sodium

Answer: (A)

Citrate is the substance responsible. Stored blood is preserved with citrate as an anticoagulant, and when that blood is transfused, citrate binds freely available calcium in the recipient’s blood. This binding lowers ionized calcium, the form that’s active in muscle contraction and cardiac function, leading to hypocalcemia. The effect can be more pronounced with rapid or massive transfusions or when liver function is compromised, because citrate metabolism slows and the calcium-chelating effect lasts longer. Magnesium, potassium, and sodium aren’t the primary drivers of transfusion-associated hypocalcemia; potassium may rise with cell breakdown, but it doesn’t cause the drop in calcium.

Citrate is the substance responsible. Stored blood is preserved with citrate as an anticoagulant, and when that blood is transfused, citrate binds freely available calcium in the recipient’s blood. This binding lowers ionized calcium, the form that’s active in muscle contraction and cardiac function, leading to hypocalcemia. The effect can be more pronounced with rapid or massive transfusions or when liver function is compromised, because citrate metabolism slows and the calcium-chelating effect lasts longer. Magnesium, potassium, and sodium aren’t the primary drivers of transfusion-associated hypocalcemia; potassium may rise with cell breakdown, but it doesn’t cause the drop in calcium.