Which two analytes increase when serum is stored at room temperature?

Which two analytes increase when serum is stored at room temperature?

• A. Calcium and Albumin
• B. Lactate and Ammonia
• C. Glucose and Cholesterol
• D. Lipid and Bilirubin

Answer: (B)

When serum is stored at room temperature, the cells present in the sample continue to metabolize. Glycolysis proceeds in red cells and leukocytes, converting glucose to lactate, so lactate levels rise even after collection. At the same time, amino acids are deaminated by these cells (and potentially by any bacteria present), increasing ammonia. These metabolic activities are faster at room temperature, whereas cooling slows them down and preserves the original concentrations. Therefore, lactate and ammonia are the analytes that tend to increase under these conditions.

When serum is stored at room temperature, the cells present in the sample continue to metabolize. Glycolysis proceeds in red cells and leukocytes, converting glucose to lactate, so lactate levels rise even after collection. At the same time, amino acids are deaminated by these cells (and potentially by any bacteria present), increasing ammonia. These metabolic activities are faster at room temperature, whereas cooling slows them down and preserves the original concentrations. Therefore, lactate and ammonia are the analytes that tend to increase under these conditions.