An aid to the early detection and management of diabetic nephropathy: assessment of a new point of care microalbuminuria system in the diabetic clinic.

Abstract

To compare the performance of the DCA2000 microalbuminuria system for albumin and creatinine concentrations and the albumin:creatinine ratio (ACR) with laboratory measurements in the hospital diabetes clinic and to assess the ease of use and applicability by standard clinic personnel. Urine albumin and creatinine concentration and ACR were measured in 154 diabetic patient samples and in 77 normal subjects. Both albumin assays are based on immunoturbidimetry. The DCA2000 system utilizes reagent cartridges processed automatically. Control material within-run precision (coefficient of variation (CV)) for albumin and creatinine ranged up to 7.1% and 3.3% respectively. Between-run CVs ranged from 2.1% to 4.3%. Method comparisons yielded correlation coefficients > 0.99 for albumin, creatinine and ACR, only a small negative bias of 3.2 mg/l for albumin and 0.10 mg/mmol for ACR, no concentration-related bias for ACR and no between-method difference for either albumin (P = 0.195) or ACR (P = 0.341). At a laboratory albumin concentration cut-off of 20 mg/l the sensitivity, specificity, negative and positive predictive values were 92.4% 100% 92.7% and 100%. Normal reference range mean albumin, creatinine and ACR values for the DCA2000 and the laboratory were 7.7 mg/l vs. 9.0 mg/l 13.0 mmol/l vs. 12.6 mmol/l and 0.66 mg/mmol vs. 0.81 mg/mmol respectively. Clinic personnel found that the DCA2000 system was easy to use suited the clinic environment and generated confidence in the results. This point of care system safely substitutes laboratory-based measurements. Ease of use and low cost make it suitable for screening and monitoring diabetes treatment. It facilitates the use of random urines, and may obviate the need for timed samples. This approach has a clear place in the battle to reduce the diabetic vascular disease burden.