Evaluation measurement of urinary albumin in population survey

Abstract

Objective To evaluate the spot urine sample collection method and value of urinary albumin measurement in population survey. Methods Six hundred and fifty-nine Beijing residents were requested to collect 24 h urine for detection of UAER, as well as random spot urine samples and morning urine samples in the next day. Rapid semi-quantitative urinary albumin-specific dipstick and ACR were measured in each spot urine specimen. The 24 h UAER was measured as golden standard to generate ROC curves and evaluate the sensitivity, specificity and AUC of each method. Results The value of ACR in the morning spot urine samples and random spot urine samples were 9. 36(5. 12-33.29) mg/g and 11.29(6. 34-41.29) mg/g respectively and there was no significant difference between these two groups (t = - 1. 382,P＞0.05). The correlation was significant in the two groups (r = 0.932, P ＜ 0.01). The correlation coefficient between ACR in the morning spot urine samples and UAER was 0. 853 (P ＜ 0. 01). The correlation coefficient between ACR in the random spot urine samples and UAER was 0. 874 (P ＜0. 01).The sensitivity and specificity of ACR for diagnosis of albuminuria in the random urine samples were 77. 9% and 91.0%. The sensitivity and specificity of ACR for diagnosis of albuminuria in the morning urine samples were 78. 4% and 95.7%. Concerning the semi-quantitative urinary albumin-specific dipstick, sensitivity and specificity were 90. 3% and 41.1% , respectively. The specificity was much lower than that of ACR. The area under the ROC curves of ACR in the random urine specimens and the morning urine specimens was 0. 918 ±0. 012, 0. 929 ± 0. 015, respectively. There was no statistical difference between these two groups (χ2 =2. 13, P＞0. 05). The area under the ROC curves of semi-quantitative urinary albumin-specific dipstick in the random urine specimens was 0.661 ±0.021, lower than that of ACR (χ2 = 248.41, P＜0.01).Conclusion Measurement of ACR in random urine samples is a reasonable method with simplicity and accuracy for the detection of albuminuria in general population screening program. Key words: Albuminuria; Urinalysis Albumins; Creatinine; Kidney failure,chronic; Epidemiological studies