title: Estimating the glomerular filtration rate using serum cystatin C levels in patients with spinal cord injuries.
abstract: METHODS
  Prospective cohort study.
  
  
  OBJECTIVE
  To investigate the relationship between (51)chromium-ethylene-diamine-tetra-acetate ((51)Cr-EDTA) clearance, serum cystatin C (CysC), serum creatinine, creatinine clearance and estimated glomerular filtration rate (eGFR(MDRD), MDRD stands for modification of diet in renal disease) based on the serum creatinine in patients with complete or incomplete spinal cord injury (SCI) and to develop and evaluate a GFR-estimating equation using serum CysC.
  
  
  METHODS
  Spinal Cord Injury Unit, Viborg Regional Hospital, Viborg, Denmark.
  
  
  METHODS
  Ninety-eight men and 47 women with SCI were included in the study. Serum CysC levels were measured by an automated particle-enhanced nephelometric immunoassay, serum and urine creatinine levels were measured by an enzymatic method traceable to the IDMS creatinine reference method, and (51)Cr-EDTA clearance was measured by a multiple plasma sample method.
  
  
  RESULTS
  The area under the curves (AUCs) in the non-parametric receiver operating characteristics (ROC) plots for serum CysC were compared with serum creatinine and to eGFR(MDRD) and revealed a significant difference (P-value < 0.05) for all SCI patients. There was no significant difference between the AUC for serum CysC compared with the AUC for creatinine clearance. GFR (ml min(-1) per 1.73 m(2)) can be calculated from serum CysC values (mg l(-1)) using the equation eGFR(CysC) = 212·exp(0.914·CysC). The model accurately predicted the GFR of 88% of patients within ± 30% of the measured GFR, and it was able to predict the GFR of 50% of patients within ± 10% of the measured GFR.
  
  
  CONCLUSIONS
  In patients with SCI, GFR can be estimated independent of age, sex and muscle mass by a newly developed equation based on a single serum CysC value.
authors.affiliation: Department of Clinical Biochemistry, Viborg Regional Hospital, Viborg, Denmark. erland.erlandsen@viborg.rm.dk
authors.forename: E J
authors.initials: EJ
authors.lastname: Erlandsen
authors.forename: R M
authors.initials: RM
authors.lastname: Hansen
authors.forename: E
authors.initials: E
authors.lastname: Randers
authors.forename: L E
authors.initials: LE
authors.lastname: Petersen
authors.forename: J
authors.initials: J
authors.lastname: Abrahamsen
authors.forename: I L
authors.initials: IL
authors.lastname: Johannesen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001830:Body Surface Area; D002648:Child; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013119:Spinal Cord Injuries / Q000097:blood* / Q000175:diagnosis; D055815:Young Adult
chemical_list: D055316:Cystatin C; D003404:Creatinine