title: Overview of the in vitro stability of commonly measured vitamins and carotenoids in whole blood.
abstract: BACKGROUND
  The pre-analytical stabilities of vitamins A, E, K, B1, B2, B6, B12, C, carotenoids and folates in whole blood were studied. The aim of this work was to provide clear and workable pre-analytical procedures specifying optimal delay before freezing for laboratories which perform themselves such analyses or which receive and transfer such specimens to referral laboratories.
  
  
  METHODS
  The stability of vitamins was studied in whole blood at room temperature after light exposure up to 24 h (vitamin C), 48 h (vitamins A, E, B1, B2, B6 and carotenoids) and 72 h (vitamins K, B12, red blood cell (RBC) and serum folates). Vitamin C stability after baseline acidification was analysed up to 48 h. Changes observed were compared to a clinical cut-off defined as total change limit based on a combination of analytical performance and within-subject variation.
  
  
  RESULTS
  Clinically and statistically significant changes occurred only in vitamins C (-22.5%), B6 (+9.9%) and serum folates (-16.8%) concentrations after 6, 24 and 48 h, respectively. Vitamins A, E, K, B1, B2, B12, RBC folates and carotenoids showed good stability up to 48 or 72 h. Vitamin C in acidified serum conserved at room temperature appeared unstable. The optimal condition for acidified vitamin C conservation was at less than -20℃.
  
  
  CONCLUSIONS
  The majority of vitamins remain stable for up to 48 h. Vitamin C quantification requires serum acidification followed by freezing as soon as possible. Freezing, respectively, within 12 h and 24 h for determination of plasma vitamin B6 and serum folates concentrations is recommended.
authors.affiliation: Biochemistry Department, Lyon Sud Hospital, Hospices Civils de Lyon, Lyon, France INSERM U1060, CarMeN Laboratory, Lyon 1 Claude Bernard University, Oullins, France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Cuerq
authors.affiliation: INSERM U1060, CarMeN Laboratory, Lyon 1 Claude Bernard University, Oullins, France Paediatric Nutrition Department, Hôpital Femme-Mère-Enfant, Hospices Civils de Lyon, Lyon, France Faculté de Médecine Lyon Est, Université Claude Bernard Lyon 1, UCBL, Lyon, France.
authors.forename: Noël
authors.initials: N
authors.lastname: Peretti
authors.affiliation: Biochemistry Department, Lyon Sud Hospital, Hospices Civils de Lyon, Lyon, France INSERM U1060, CarMeN Laboratory, Lyon 1 Claude Bernard University, Oullins, France.
authors.forename: Karim
authors.initials: K
authors.lastname: Chikh
authors.affiliation: Biochemistry Department, Lyon Sud Hospital, Hospices Civils de Lyon, Lyon, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Mialon
authors.affiliation: Biochemistry Department, Lyon Sud Hospital, Hospices Civils de Lyon, Lyon, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Guillaumont
authors.affiliation: Biochemistry Department, Lyon Sud Hospital, Hospices Civils de Lyon, Lyon, France INSERM U1060, CarMeN Laboratory, Lyon 1 Claude Bernard University, Oullins, France.
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Drai
authors.affiliation: Biochemistry Department, Lyon Sud Hospital, Hospices Civils de Lyon, Lyon, France INSERM U1060, CarMeN Laboratory, Lyon 1 Claude Bernard University, Oullins, France emilie.blond@chu-lyon.fr.
authors.forename: Emilie
authors.initials: E
authors.lastname: Blond
mesh_terms: D000328:Adult; D002338:Carotenoids / Q000097:blood* / Q000737:chemistry / Q000528:radiation effects; D002624:Chemistry, Clinical / Q000379:methods*; D003080:Cold Temperature; D005260:Female; D005492:Folic Acid / Q000097:blood* / Q000737:chemistry / Q000528:radiation effects; D005602:France; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D008297:Male; D008875:Middle Aged; D010949:Plasma / Q000737:chemistry; D011786:Quality Control; D015203:Reproducibility of Results; D044967:Serum / Q000737:chemistry; D013997:Time Factors; D014815:Vitamins / Q000097:blood* / Q000737:chemistry / Q000528:radiation effects; D055815:Young Adult
chemical_list: D014815:Vitamins; D002338:Carotenoids; D005492:Folic Acid
keywords: Quality assurance and control; chromatography; nutrition