Abstract

Back ground and Objectives: Urine albumin measurements are used in patient care, epidemiological studies, and in clinical trials for which the samples are often stored at different temperatures and for a variable duration of time. Proper storage technique is the need of the hour to preserve the albumin concentration as measurement errors can have serious implications on the study results. Therefore, this study intended to observe the effect of storage temperatures and duration of storage on low concentrations of urinary albumin (microalbuminuria) in patients of diabetes mellitus.

Methods: Single random urine sample which is dipstick negative for protein was collected from 44 patients with diabetes mellitus. The samples were analysed immediately and then stored at -20ºC and 4ºC for 1week and 4weeks and reanalysed. The urinary albumins in the above samples were re-estimated at the end of 1 week and again at the end of 4 weeks. The difference in albumin levels between the fresh samples and after
storage was noted and statistically analysed.

Results: Urinary albumin concentration decreased with the increase in duration of storage. Storage at -20°C showed a larger decrease in urinary albumin concentration as compared to those stored at 4°C. Conclusion: Estimation of microalbumin should be performed in a fresh sample of urine and if storage is imperative, the sample may be stored at 4°C and the estimation carried out in less than a week.

Key words: Albuminuria; preservation;diabetes mellitus.