title: Measurement of amino terminal propeptide of type III procollagen (PIIINP) employing the ADVIA Centaur platform. Validation, reference interval and comparison to UniQ RIA.
abstract: BACKGROUND
  Recently, measurement of amino terminal propeptide of type III procollagen (PIIINP) was introduced as a part of the hepatic cirrhotic marker enhanced liver fibrosis™ test on the automated ADVIA Centaur(®) immunoassay platform (Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA). In this article, we show that the Centaur PIIINP may be used in place of the much more labor-intensive RIA method, and we present an age stratified reference interval.
  
  
  METHODS
  We analyzed four control samples 20 times over a period of 5 days. Centaur PIIINP assay measurements were compared with the widely used UniQ PIIINP RIA assay (Orion Diagnostica, Espoo, Finland) using 55 patient samples (range=3.7-43.3 µg/L). Furthermore, we established a reference interval based on samples from 287 blood donors.
  
  
  RESULTS
  In the concentration range 2.5-11.9 µg/L, the total imprecision was below 8%. Comparison with the UniQ PIIINP RIA assay yielded: Centaur PIIINP µg/L = 1.9 × (UniQ PIIINP RIA) + 0.6 µg/L, r2=0.94. The reference interval for the Centaur PIIINP assay showed no gender difference but was stratified by age [4.0-11.0 µg/L (18-40 years) and 3.5-9.5 µg/L (41-70 years)].
  
  
  CONCLUSIONS
  We conclude that the Centaur PIIINP assay is suitable for routine use with our newly defined reference interval. The results obtained by Centaur correlates well with those obtained by the previously employed RIA, though the absolute values are higher.
authors.forename: Cindy Soendersoe
authors.initials: CS
authors.lastname: Knudsen
authors.forename: Lene
authors.initials: L
authors.lastname: Heickendorff
authors.forename: Ebba
authors.initials: E
authors.lastname: Nexo
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D001331:Automation; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000592:standards; D008103:Liver Cirrhosis / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood* / Q000276:immunology / Q000592:standards; D011347:Procollagen / Q000097:blood* / Q000276:immunology / Q000592:standards; D011863:Radioimmunoassay; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D012737:Sex Factors; D054928:Validation Studies as Topic; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D010446:Peptide Fragments; D011347:Procollagen; D011933:Reagent Kits, Diagnostic; C041876:procollagen Type III-N-terminal peptide