[Urinary dipsticks must not be used to detect diabetes-induced incipient nephropathy]

Microalbuminuria is an early indication of diabetic nephropathy in patients with Type 1 diabetes and a marker of cardiovascular in patients with type 2 diabetes. It must therefore be assessed annually in these patients. We sought to determine whether semiquantitative determination of proteinuria with urinary dipsticks was useful for this purpose.

This analysis of consecutive urinary samples among diabetic patients excluded those with dipstick results positive either for leukocyturia or nitrituria, to avoid false positives due to urinary infection. We assessed the reliability of the dipsticks in comparison with conventional microalbuminuria and proteinuria assays.

The study included 230 patients. Positive dipstick results had good positive (95.7%) and negative (93.9%) predictive values. Low levels of microalbuminuria, however - those that lead to early adjustment of treatment, were much more difficult to identify: the negative predictive value was only 73.7% and proteinuria was no longer correlated with microalbuminuria.

Urinary dipsticks cannot replace conventional assays for microalbuminuria or proteinuria.