title: Comparison between IDMS-traceable Jaffe and enzymatic creatinine assays for estimation of glomerular filtration rate by the CKD-EPI equation in healthy and diabetic subjects.
abstract: OBJECTIVE
  The aim of this paper was to compare the agreement between creatinine measured by Jaffe and enzymatic methods and their putative influence on eGFR as calculated by the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation in healthy and diabetic individuals.
  
  
  METHODS
  Cross-sectional study conducted in 123 adult southern Brazilians with GFR>60 mL/min/1.73 m² (53 patients with type 2 diabetes, 70 healthy volunteers). Mean age was 49±16 years (range of 19-86). Most were female (55%) and white (83%). Creatinine was measured by a traceable Jaffe method (Modular P, Roche Diagnostic) and by an enzymatic method (CREA plus, Roche/Hitachi 917). GFR was measured by the ⁵¹Cr-EDTA single-injection method.
  
  
  RESULTS
  Serum creatinine measured by the Jaffe and enzymatic methods was similar in healthy subjects (0.79±0.16 vs. 0.79±0.15 mg/dL, respectively, P=0.76), and diabetic patients (0.96±0.22 vs. 0.92±0.29 mg/dL, respectively, P=0.17). However, the correlation between the two methods was higher in the healthy group (r=0.90 vs. 0.76, P<0.001). The difference between Jaffe creatinine and enzymatic creatinine was <10% in 63% of cases in the healthy group and 40% of cases in the diabetes group (P=0.018). In the subset of patients with diabetes, eGFR based on enzymatic assay results showed better agreement with measured GFR than did eGFR based on Jaffe results.
  
  
  CONCLUSIONS
  Jaffe and enzymatic creatinine methods show adequate agreement in healthy subjects, but in the presence of diabetes, the enzymatic method performed slightly better.
authors.affiliation: Graduate Program in Medical Science: Endocrinology, Universidade Federal do Rio Grande do Sul (UFRGS), Brazil.
authors.forename: Amanda Veiga
authors.initials: AV
authors.lastname: Cheuiche
authors.forename: Ariana Aguiar
authors.initials: AA
authors.lastname: Soares
authors.forename: Eduardo Guimarães
authors.initials: EG
authors.lastname: Camargo
authors.forename: Letícia Schwerz
authors.initials: LS
authors.lastname: Weinert
authors.forename: Joíza Lins
authors.initials: JL
authors.lastname: Camargo
authors.forename: Sandra Pinho
authors.initials: SP
authors.lastname: Silveiro
mesh_terms: D000328:Adult; D001938:Brazil; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology; D057075:Enzyme Assays / Q000706:statistics & numerical data*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D003404:Creatinine
keywords: CKD-EPI; Chronic Kidney Disease Epidemiology Collaboration; Creatinine; Diabetes mellitus; Enzymatic; Glomerular filtration rate; Jaffe; Kidney function; MDRD; Modification of Diet in Renal Disease; eGFR; estimated glomerular filtration rate