The utility of conventional dipsticks for urinary protein for screening of
microalbuminuria in diabetic patients
Supamai Soonthornpun, Asst. Prof., D. of Internal Medicine, F. of Medicine, PSU.
Natawan Thammakumpee, Scientist, D. of Internal Medicine, F. of Medicine, PSU.
Atchara Thamprasit, Nurse, D. of Internal Medicine, F. of Medicine, PSU.
Chatchalit Rattarasarn, Assoc. Prof., D. of Internal Medicine, F. of Medicine, PSU.
Rattana Leelawattana, Asst. Prof., D. of Internal Medicine, F. of Medicine, PSU.
Worawong Setasuban, D. of Internal Medicine, F. of Medicine, PSU.
Corresponding e-mail : ssupamai@ratree.psu.ac.th
Grant : Prince of Songkla University
Published : J Med Assoc Thai 2000, 83 : 797-803
Key words : dipsticks, microalbuminuria, urinary protein, diabetes mellitus
The demonstration that microalbuminuria is predictive of overt diabetic nephropathy has
created a demand for the routine measurement of urinary albumin in diabetic patients. We assessed the sensitivity, specificity, positive and negative predictive values of the conventional dipsticks for uri-nary protein (Ames Multistix, Bayer Diagnostic, Australia) as the screening test for microalbuminuria in diabetic patients compared with Micral-Test II (Boehringer Mannheim, Germany). Radioimmuno-assay for albumin was taken as standard for comparison. With the urinary albumin concentration of
20 mg/L as a discriminating level of microalbuminuria, Micral-Test II had a sensitivity of 98.8
percent and a specificity of 68.6 percent whereas Ames Multistix had lower sensitivity but higher specificity. If urinary albumin concentration of 60 mg/L was used instead as a discriminating level of microalbuminuria, none of Ames Multistix by visual reading and only 5 of 32 (15.6%) of those by reflectance photometer had false negative results. By visual reading, the sensitivity of Ames Multi-
stix was increased from 68.1 to 100 percent with the drop in specificity from 85.7 to 50.2 percent.
On the other hand, the sensitivity was increased from 37.4 to 84.4 percent but the specificity was maintained if reflectance photometer was used. In conclusion, Ames Multistix was less sensitive than Micral-Test II in detection of urinary albumin concentration above 20 mg/L. At higher urinary
albumin concentration above 60 mg/L which indicates a clinically significant microalbuminuria, the sensitivity of Ames Multistix was increased to 100 percent. Ames Multistix which is much less expensive than Micral-Test II, can be used as the screening test for significant microalbuminuria in clinical practice particularly in cases having financial problems.
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