Abstract: FR-PO754

Comparison of Spot Urinary Protein to Creatinine Ratio to 24 Hours Urinary Protein at Different Time Points During the Day: Is There a Variability During the Day?

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Sabir, Omer, Fatima Memorial School of Health Sciences, University of health Sciences, Lahore, Pakistan
  • Riaz, Muhammad Mohsin, Fatima Memorial School of Health Sciences, University of health Sciences, Lahore, Pakistan
  • Tarif, Nauman, Fatima Memorial School of Health Sciences, University of health Sciences, Lahore, Pakistan
  • Rehman, Abaid Ur, Fatima Memorial School of Health Sciences, University of health Sciences, Lahore, Pakistan
  • Rafique, Kashif, Fatima Memorial School of Health Sciences, University of health Sciences, Lahore, Pakistan
  • Rizvi, Nabiha, Fatima Memorial School of Health Sciences, University of health Sciences, Lahore, Pakistan
Background

24 hours urinary protein excretion is considered gold standard for the estimation of daily urinary protein loss, although cumbersome. We compared the spot urinary protein to creatinine ratio (PCR) collected at three different time points of the day with standard 24 urine protein collection to identify the best time for sampling.

Methods

This was an observational, cross sectional study carried out at Fatima Memorial Hospital Lahore, Pakistan over four years from January 2013. Sixty-seven (67) patients who were persistently dipstick positive for protein were included and informed consent was obtained. The patients were required to collect a twenty-four hours urine sample according to standard recommendations for protein and creatinine measurement. From the same collection 10 ml aliquots of urine were separated and sent for spot urinary protein and spot urinary creatinine for PCR at different time points ( Morning: 8 AM – 10 AM; Evening : 2 PM – 6 PM; Night: 8 PM – 10 PM).

Results

Mean age of the cohort was 32.91+ 13.12 years and 39 (58.2%) were males. Mean Serum Creatinine was 3.24 + 2.50 mg/dL (mean eGFR by CKD-EPI equation: 45.1 + 37.3 ml/min. Range: 5.7 – 147.5 ml/min). 37.3% were diabetic and were clinically designated as having diabetic nephropathy whereas the rest were undergoing evaluation or had biopsy proven glomerulonephritis. Patients were classified as CKD Class I: 18.6%, Class II: 15.3%, Class III: 23.7%, Class IV: 16.9% and Class V: 25.4%. None of the patient was on renal replacement therapy at the time of cross section. Mean serum albumin of the cohort was 3.23 + 0.63 g/dL (Range: 1.9 to 4.7 g/dL.); whereas mean 24 hours urinary protein was 2.0 + 1.58 g/day (Range: 0.73 – 6.5 g/day). Pearson’s correlations for all three spot PCR samples were significantly correlated with the 24 hours urinary protein sample, however night time spot sample was found to have strongest correlation (Pearson’s r: 0.64, p 〈 0.05) as compared to early morning and evening samples (r = 0.41 and r = 0.37 respectively, p < 0.05 for both).

Conclusion

Our study shows that nighttime sampling for spot PCR may better correlate with 24 hours urinary protein excretion. Further studies in different CKD stages and ethnicities could confirm the findings of our study.