The Effect of Sample Storage on Total Cholesterol and Hdl-cholesterol Assays

The result of sample analysis is said to be as good as the sample collection and preparation. Without adequate sample handling, accuracy and precision of sample analysis will be greatly affected. The effect of sample storage temperature and length of storage time on serum total cholesterol (TC) and HDL-cholesterol (HDL-C) assays was studied using twenty different samples, pooled into three. Each pool was split into three and stored at different temperaturesroom temperature (16 25 /C), refrigerator (4 /C) and freezer temperature (-20 /C), for 6, 30 ad 51 days respectively. The observations from the results obtained using day zero as control showed that the TC concentration in the samples stored at room temperature increased with the length of storage time. How ever, these increases were not statistically significant (P>0.05), for the duration of the study. HDL-C concentration was found to be significantly increased (p=0.0211 and 0.0117) from day 2 and 10, at room and refrigerator temperatures respectively. However, there was no statistically significant difference (P>0.05) in the samples stored at freezer temperature in both TC and HDL-C concentrations. Except for the TC concentration in the sample stored at freezer temperature, the samples showed a significant correlation at room, refrigerator and freezer temperatures respectively with the duration of storage. From this study, it can be concluded that the concentrations of TC and HDL-C in stored samples are both time and temperature dependent. Also, the concentration is mostly affected at room temperature and least affected at freezer temperature. Hence, if samples for TC and HDL-C assays are to be stored , freezer temperature is highly preferred.