title: Preanalytical stability of adrenocorticotropic hormone depends on both time to centrifugation and temperature.
abstract: OBJECTIVE
  The purpose of our study was to analyze the effects of temperature, time delay, and time to centrifugation on the stability of human plasma adrenocorticotropin (ACTH) measurements.
  
  
  METHODS
  Twenty-one EDTA whole blood sample pools were centrifuged at 1100 ×g for 10 minutes at 4°C either immediately or after storage for 2, 4, 8, and 24 hours at 4°C or room temperature. Plasma ACTH was then measured either immediately or after 2, 4, 8, and 24 hours storage at 4°C or room temperature.
  
  
  RESULTS
  The change in ACTH concentrations was affected significantly (from 8.1±5.0% to 12.4±2.9% at 4 hours, P<.005) by time to centrifugation at room temperature. However, it remained stable (<5% change) up to 8 hours at 4°C in samples both centrifuged immediately and uncentrifuged.
  
  
  CONCLUSIONS
  To get accurate values of plasma ACTH concentrations, if the samples cannot be transferred to the laboratory for analysis at room temperature within 2 hours, they should be immediately stored at 4°C, and analyzed within 8 hours.
authors.affiliation: Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.
authors.forename: Zhi-Qi
authors.initials: ZQ
authors.lastname: Wu
authors.affiliation: Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.
authors.forename: Hua-Guo
authors.initials: HG
authors.lastname: Xu
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood* / Q000737:chemistry*; D000328:Adult; D000368:Aged; D001800:Blood Specimen Collection / Q000379:methods / Q000592:standards*; D002498:Centrifugation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055550:Protein Stability; D013696:Temperature; D013997:Time Factors; D055815:Young Adult
chemical_list: D000324:Adrenocorticotropic Hormone
keywords: adrenocorticotropic hormone; preanalytical; stability; temperature