Which factor can cause false decreases in serum glucose levels?

Which factor can cause false decreases in serum glucose levels?

• A. Prolonged contact with red blood cells before separating the serum
• B. Refrigerating the serum sample before analysis
• C. Freezing the serum sample before analysis
• D. A lipemic sample

Answer: (A)

The main idea is that glucose is consumed by cells in the blood after collection. When serum is not separated promptly, red blood cells continue glycolysis, using up glucose and lowering its level in the sample. This leads to a falsely decreased glucose result. To prevent this, either separate the serum promptly or use a method that inhibits glycolysis (such as a glycolysis-inhibiting tube) and/or keep the sample cold to slow cellular metabolism. Refrigerating the serum after separation doesn’t cause the decrease, freezing can cause other artifacts like hemolysis, and a lipemic sample can interfere with some assay methods but doesn’t specifically cause a true drop in glucose from ongoing glycolysis.

The main idea is that glucose is consumed by cells in the blood after collection. When serum is not separated promptly, red blood cells continue glycolysis, using up glucose and lowering its level in the sample. This leads to a falsely decreased glucose result. To prevent this, either separate the serum promptly or use a method that inhibits glycolysis (such as a glycolysis-inhibiting tube) and/or keep the sample cold to slow cellular metabolism. Refrigerating the serum after separation doesn’t cause the decrease, freezing can cause other artifacts like hemolysis, and a lipemic sample can interfere with some assay methods but doesn’t specifically cause a true drop in glucose from ongoing glycolysis.