title: Intra-individual variation in creatinine and cystatin C.
abstract: BACKGROUND
  Serum creatinine and cystatin C are measured in the assessment of glomerular filtration rate. Biological variation of an analyte is an important determinant of its usefulness. Intra-individual variation in serum creatinine and cystatin C in healthy subjects was determined in this study.
  
  
  METHODS
  Weekly blood samples were taken from 10 healthy subjects and analysed for creatinine (kinetic Jaffe method) and for cystatin C (by nephelometry).
  
  
  RESULTS
  Intra-individual variations for serum creatinine and cystatin C were 6.1% and 4.55%, respectively. Index of individuality values were similar for the analytes (0.35 for both).
  
  
  CONCLUSIONS
  Intra-individual variations for serum creatinine and cystatin C were similar in healthy subjects.
authors.affiliation: Department of Chemical Pathology, St. Thomas' Hospital, London, UK.
authors.forename: Niluka
authors.initials: N
authors.lastname: Bandaranayake
authors.forename: Thelma
authors.initials: T
authors.lastname: Ankrah-Tetteh
authors.forename: Sethsiri
authors.initials: S
authors.lastname: Wijeratne
authors.forename: Ramasamyiyer
authors.initials: R
authors.lastname: Swaminathan
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods*; D002624:Chemistry, Clinical / Q000379:methods*; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D003404:Creatinine