The adaptation of an immunoturbidimetric assay to quantitatively measure urinary albumin is described and this was used to evaluate a commercial latex agglutination slide test, Albuscreen, with a sensitivity of 25 mg/l. Excellent agreement was observed between the two methods, and in clinical studies an acceptable classification of patients was made using Albuscreen, an albumin: creatinine ratio of less than or equal to 2.5 being used to indicate possible microalbuminuria. A small number of false negative and false positive results occurred in some dilute and concentrated urine samples, respectively.