title: The effect of blood collection procedure on plasma renin activity (PRA) and concentrations of direct renin (DRC) and aldosterone.
abstract: BACKGROUND
  Performing measurements of plasma renin activity (PRA) or direct renin concentration (DRC) and aldosterone concentration, we should be well informed about requirements concerning blood sample processing.
  
  
  METHODS
  Forty-seven patients had blood collected in the supine and upright positions. Blood was withdrawn into two EDTA2K tubes and one with clot activator. One EDTA2K tube was cooled at +4 °C and centrifuged at +4 °C whereas the other was prepared at room temperature. PRA and DRC were measured by radioimmunoassay (RIA) and radioimmunometry (IRMA), respectively, in both cooled and not cooled plasma samples, and aldosterone was measured by RIA in not cooled plasma and in serum.
  
  
  RESULTS
  In all the groups, with low, medium, and high values of PRA and direct renin, the temperature of sample processing within 30 minutes had no marked influence on the final result (correlation coefficient for renin was 0.9994, and for PRA, 0.8297). The measured concentrations of aldosterone also showed high correlation (r = 0.9790) but were markedly higher in plasma.
  
  
  CONCLUSIONS
  The measurements of DRC, and to a lesser extent PRA, were similar regardless of temperature condition during the 20-30 minutes necessary for blood sample processing. Aldosterone concentrations in plasma vs serum samples appeared to be markedly higher.
authors.affiliation: Department of Endocrinology, The Medical Centre of Postgraduate Education, Poland glinicki@cmkp.edu.pl.
authors.forename: Piotr
authors.initials: P
authors.lastname: Glinicki
authors.affiliation: Department of Endocrinology, The Medical Centre of Postgraduate Education, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Jeske
authors.affiliation: Department of Endocrinology, The Medical Centre of Postgraduate Education, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Gietka-Czernel
authors.affiliation: Department of Endocrinology, The Medical Centre of Postgraduate Education, Poland.
authors.forename: Lucyna
authors.initials: L
authors.lastname: Bednarek-Papierska
authors.affiliation: Department of Endocrinology, The Medical Centre of Postgraduate Education, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Kruszyńska
authors.affiliation: Department of Endocrinology, The Medical Centre of Postgraduate Education, Poland.
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Słowińska-Srzednicka
authors.affiliation: Department of Endocrinology, The Medical Centre of Postgraduate Education, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zgliczyński
mesh_terms: D000450:Aldosterone / Q000097:blood*; D001800:Blood Specimen Collection / Q000379:methods*; D004492:Edetic Acid; D006801:Humans; D012083:Renin / Q000097:blood*; D013696:Temperature
chemical_list: D000450:Aldosterone; D004492:Edetic Acid; D012083:Renin
keywords: Aldosterone; DRC; PRA; direct renin concentration; plasma renin activity; primary aldosteronism