Which analyte increases when serum or plasma is stored at 4°C?

Which analyte increases when serum or plasma is stored at 4°C?

• A. LD4
• B. ALP
• C. Glucose
• D. Calcium

Answer: (B)

During storage, some analytes can change because cells in the sample continue to release substances or because enzymes leak out from platelets. Alkaline phosphatase is abundant in platelets, and when serum or plasma is kept at 4°C, platelets can slowly release ALP into the liquid portion over time. This ongoing release leads to an apparent rise in ALP activity in stored samples. In contrast, glucose tends to fall during storage because residual cells keep consuming it through glycolysis, so it doesn’t increase. Calcium levels aren’t known to reliably rise with storage at this temperature, and while LDH can increase if there’s hemolysis or cell damage, its rise is more about sample integrity than a predictable storage effect at 4°C. Therefore, ALP is the analyte most likely to show an increase with storage at cold temperature.

During storage, some analytes can change because cells in the sample continue to release substances or because enzymes leak out from platelets. Alkaline phosphatase is abundant in platelets, and when serum or plasma is kept at 4°C, platelets can slowly release ALP into the liquid portion over time. This ongoing release leads to an apparent rise in ALP activity in stored samples.

In contrast, glucose tends to fall during storage because residual cells keep consuming it through glycolysis, so it doesn’t increase. Calcium levels aren’t known to reliably rise with storage at this temperature, and while LDH can increase if there’s hemolysis or cell damage, its rise is more about sample integrity than a predictable storage effect at 4°C. Therefore, ALP is the analyte most likely to show an increase with storage at cold temperature.