Quantitation of proteinuria using protein-creatinine ratio in random urine samples
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R S Iyer1, S N Shailaja, N Bhaskaranand
1Department of Pediatrics, Kasturba Medical College, Manipal, Kamataka.
Insights
Assessing proteinuria in children is simplified. A random urine protein-to-creatinine ratio reliably estimates protein excretion, avoiding lengthy 24-hour urine collections.
Area of Science:
- Pediatric Nephrology
- Clinical Chemistry
Background:
- Estimating proteinuria in children typically requires a 24-hour urine collection, which is inconvenient.
- The protein-to-creatinine ratio in urine is a potential surrogate marker for protein excretion, assuming stable glomerular filtration rate.
Purpose of the Study:
- To evaluate the reliability of the random urine protein-to-creatinine ratio for assessing proteinuria in children.
- To establish correlations between 24-hour urine protein and random urine protein-creatinine ratio.
Main Methods:
- Collected 100 urine samples (24-hour and random) from 50 children with nephrotic syndrome, 25 in remission, and 25 healthy children.
- Assessed 24-hour urine total protein and random urine protein-to-creatinine ratio.
- Performed linear regression analysis to correlate the two measurement methods.
Main Results:
- An excellent correlation (r = 0.81, p < 0.001) was found between 24-hour urine total protein and random urine protein-to-creatinine ratio.
- A ratio > 3.5 indicated massive proteinuria, while a ratio < 0.2 suggested physiological levels.
- The protein-to-creatinine ratio demonstrated high sensitivity, specificity, and predictive values for massive proteinuria.
Conclusions:
- The random urine protein-to-creatinine ratio is a reliable and convenient method for assessing proteinuria severity in pediatric patients.
- This method can replace the cumbersome 24-hour urine collection in clinical practice.
Abstract:
Estimation of proteinuria in children is cumbersome when a 24 h urine collection is needed. In the presence of a stable glomerular filtration rate, the ratio of urinary protein and creatinine should reflect the protein excretion. One hundred samples of urine (24 h and random samples) were collected from 50 children with nephrotic syndrome, 25 with nephrotic syndrome in remission and 25 normal children. The 24 h urine total protein and random urine protein-creatinine ratio were assessed on these samples. Linear regression analysis of the results showed excellent correlation between the values (r = 0.81, p less than 0.001). A random urine protein-creatinine ratio of greater than 3.5 correlated with massive proteinuria, while a ratio less than 0.2 was suggestive of physiological values. The sensitivity, specificity, positive and negative predictive values of the protein-creatinine ratio in massive proteinuria were very high. We conclude that the random urine protein-creatinine ratio can be used reliably to assess the degree of proteinuria in children.