title: Inorganic Phosphorus and Potassium Are Putative Indicators of Delayed Separation of Whole Blood.
abstract: OBJECTIVE
  The delayed separation of whole blood can influence the concentrations of circulating blood components, including metabolites and cytokines. The aim of this study was to determine whether clinical-biochemistry analytes can be used to assess the delayed separation of whole blood.
  
  
  METHODS
  We investigated the plasma and serum concentrations of five clinical-biochemistry analytes and free hemoglobin when the centrifugation of whole blood stored at 4°C or room temperature was delayed for 4 hours, 6 hours, 24 hours, or 48 hours, and compared the values with those of matched samples that had been centrifuged within 2 hours after whole-blood collection.
  
  
  RESULTS
  The inorganic phosphorus (IP) levels in the plasma and serum samples were elevated ≥ 1.5-fold when whole-blood centrifugation was delayed at room temperature for 48 hours. Furthermore, the IP levels in the plasma samples showed excellent assessment accuracy [area under the receiver-operating-characteristic curve (AUC) > 0.9] after a 48-hour delay in whole-blood separation, and high sensitivity (100%) and specificity (95%) at an optimal cutoff point. The IP levels in the serum samples also exhibited good assessment accuracy (AUC > 0.8), and high sensitivity (81%) and specificity (100%). The potassium (K(+)) levels were elevated 1.4-fold in the serum samples following a 48-hour delay in whole-blood separation. The K(+) levels showed excellent assessment accuracy (AUC > 0.9) following a 48-hour delay in whole-blood separation, and high sensitivity (95%) and specificity (91%) at an optimal cutoff point.
  
  
  CONCLUSIONS
  Our study showed that the IP and K(+) levels in the plasma or serum samples could be considered as putative indicators to determine whether whole-blood separation had been delayed for extended periods.
authors.affiliation: National Biobank of Korea, Center for Genome Sciences, Korea National Institute of Health, Cheongju, Korea.
authors.forename: Jae-Eun
authors.initials: JE
authors.lastname: Lee
authors.affiliation: National Biobank of Korea, Center for Genome Sciences, Korea National Institute of Health, Cheongju, Korea.
authors.forename: Maria
authors.initials: M
authors.lastname: Hong
authors.affiliation: National Biobank of Korea, Center for Genome Sciences, Korea National Institute of Health, Cheongju, Korea.
authors.forename: Seul-Ki
authors.initials: SK
authors.lastname: Park
authors.affiliation: National Biobank of Korea, Center for Genome Sciences, Korea National Institute of Health, Cheongju, Korea.
authors.forename: Ji-In
authors.initials: JI
authors.lastname: Yu
authors.affiliation: National Biobank of Korea, Center for Genome Sciences, Korea National Institute of Health, Cheongju, Korea.
authors.forename: Jin-Sook
authors.initials: JS
authors.lastname: Wang
authors.affiliation: Department of New Health Technology Assessment Research, National Evidence-Based Healthcare Collaborating Agency, Seoul, Korea.
authors.forename: Haewon
authors.initials: H
authors.lastname: Shin
authors.affiliation: Department of Laboratory Medicine, Dankook University Medical College, Cheonan, Korea.
authors.forename: Jong-Wan
authors.initials: JW
authors.lastname: Kim
authors.affiliation: National Biobank of Korea, Center for Genome Sciences, Korea National Institute of Health, Cheongju, Korea.
authors.forename: Bok-Ghee
authors.initials: BG
authors.lastname: Han
authors.affiliation: National Biobank of Korea, Center for Genome Sciences, Korea National Institute of Health, Cheongju, Korea.
authors.forename: So-Youn
authors.initials: SY
authors.lastname: Shin
keywords: clinical biochemistry; plasma; preanalytical variation; serum; stability