Clinical utility of trace proteinuria for microalbuminuria screening in the general population.
BACKGROUND
The urine dipstick test that regards > 1+ proteinuria as positive is unsuitable for microalbuminuria screening owing to its low sensitivity in the general population. We conducted a cross-sectional survey to examine whether trace proteinuria could be an indicator of microalbuminuria.


METHODS
The subjects were 2321 participants in a community-based health check-up in Takahata, Japan. Dipstick tests for proteinuria and the urine albumin-creatinine ratio (UACR) measurement were performed with single-spot urine specimens collected early in the morning. The results of the dipstick tests were recorded as (-), trace, (1+), (2+), and (3+). Micro- and macroalbuminuria were defined as UACR 30-300 mg/g and > 300 mg/g, respectively.


RESULTS
Overall, the prevalence and median UACR levels of urine protein (-), trace, (1+), (2+), and (3+) were 92.0% (8.8 mg/g), 3.5% (43 mg/g), 2.6% (81 mg/g), 1.4% (315 mg/g), and 0.5% (1073 mg/g), respectively. Within the trace proteinuria category, the prevalence of microalbuminuria in all subjects, men, subjects >or=60 years, diabetic subjects, and hypertensive subjects was 59.3%, 73.8%, 71.2%, 88.9%, and 68.0%, respectively. By regarding trace proteinuria as positive, the sensitivity of the urine protein dipstick test for micro- and macroalbuminuria was improved (from 23.3% to 37.1%), while its specificity was not significantly changed (from 98.9% to 97.3%).


CONCLUSIONS
Trace proteinuria could be a useful indicator of microalbuminuria in the general population, and especially in subjects at high risk of cardiovascular disease.
Konta
Tsuneo
T
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan. kkonta@med.id.yamagata-u.ac.jp
Hao
Zhimei
Z
Takasaki
Satoshi
S
Abiko
Hiroshi
H
Ishikawa
Mizue
M
Takahashi
Toshiyuki
T
Ikeda
Ami
A
Ichikawa
Kazunobu
K
Kato
Takeo
T
Kawata
Sumio
S
Kubota
Isao
I
D000368:Aged; D000419:Albuminuria / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011934:Reagent Strips; D016482:Urinalysis
D011934:Reagent Strips