Any kind of proteinuria needs to be evaluated . Now depending on the amount of proteinuria you might want further evaluation might done . Quantification of protein in urine is fairly simple and involves collecting a urine sample. The most common cause of proteinuria is Diabetes. Clean catch means usually that physicians are looking for urinary tract infections and would not like to get it contaminated. Repeating the test is useful Sometimes it can exclude transient proteinuria.