title: Spot urine protein-to-creatinine ratio compared with 24-hour urinary protein in patients with kidney transplant.
abstract: OBJECTIVE
  This study sought to determine the correlation between protein-to-creatinine ratio and 24-hour urinary protein excretion, to examine agreement between the 2 methods, and to determine the discriminant value for protein-to-creatinine ratio that reliably determines significant threshold levels of proteinuria.
  
  
  METHODS
  Proteinuria was assessed by 24-hour urine protein excretion and protein-to-creatinine ratio. Correlation and limits of agreement between the 2 methods were evaluated. The discriminant cutoff values for spot urine protein-to-creatinine ratio in predicting 24-hour urine protein excretion were determined using receiver operating characteristic curves.
  
  
  RESULTS
  A positive correlation (r=0.7459, P < .0001) was found between spot urine protein-to-creatinine ratio and 24-hour urine protein excretion. A Bland-Altman plot shows that the 2 tests have reasonable limits of agreement at a low level of protein excretion, but the limits become wider as protein excretion increases. The area under the receiver operating characteristic curve for urine protein-to-creatinine ratio at various cutoffs was 0.967 (95% confidence interval: 0.880-0.996; P < .0001). The cutoff level of 0.433 had a sensitivity and specificity of 100% and 90%.
  
  
  CONCLUSIONS
  We conclude that the protein-to-creatinine ratio in spot urine specimens in patients undergoing a kidney transplant is a convenient and reliable method of estimating protein excretion in urine.
authors.affiliation: Department of Internal Medicine, Division of Nephrology, University of Jordan, Amman, Jordan.
authors.forename: Ayman M
authors.initials: AM
authors.lastname: Wahbeh
mesh_terms: D000328:Adult; D019540:Area Under Curve; D015415:Biomarkers / Q000652:urine; D003404:Creatinine / Q000652:urine*; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011507:Proteinuria / Q000175:diagnosis* / Q000209:etiology / Q000652:urine; D012372:ROC Curve; D011934:Reagent Strips; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome; D016482:Urinalysis / Q000295:instrumentation
chemical_list: D015415:Biomarkers; D011934:Reagent Strips; D003404:Creatinine