title: Capillary versus venous haemoglobin determination in the assessment of healthy blood donors.
abstract: OBJECTIVE
  To determine the accuracy of fingerstick haemoglobin assessment in blood donors, the performance of a portable haemoglobinometer (HemoCue Hb 201+) was prospectively compared with that of an automated haematology analyzer (Cell-Dyn 4000). Haemoglobin values obtained by the latter were used as the 'true' result.
  
  
  METHODS
  Capillary fingerstick samples were assayed by HemoCue in 150 donors. Fingerstick samples from two sites, one on each hand, were obtained from a subset of 50 subjects. Concurrent venous samples were tested using both HemoCue and Cell-Dyn devices.
  
  
  RESULTS
  Capillary haemoglobin values (HemoCue) were significantly greater than venous haemoglobin values (HemoCue), which in turn were significantly greater than venous haemoglobin values by Cell-Dyn (mean ± SD: 14.05 ± 1.51, 13.89 ± 1.31, 13.62 ± 1.23, respectively; P < 0.01 for all comparisons among groups). Nine donors (6%) passed haemoglobin screening criteria (≥ 12.5 g/dl) by capillary HemoCue, but were deferred by Cell-Dyn values (false-pass). Five donors (3%) were deferred by capillary sampling, but passed by Cell-Dyn (false-fail). Substantial variability in repeated fingerstick HemoCue results was seen (mean haemoglobin 13.72 vs. 13.70 g/dl, absolute mean difference between paired samples 0.76 g/dl). Hand dominance was not a factor.
  
  
  CONCLUSIONS
  Capillary samples assessed via a portable device yielded higher haemoglobin values than venous samples assessed on an automated analyzer. False-pass and false-fail rates were low and acceptable in the donor screening setting, with 'true' values not differing by a clinically significant degree from threshold values used to assess acceptability for blood donation.
authors.affiliation: Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Patel
authors.forename: R
authors.initials: R
authors.lastname: Wesley
authors.forename: S F
authors.initials: SF
authors.lastname: Leitman
authors.forename: B J
authors.initials: BJ
authors.lastname: Bryant
mesh_terms: D000328:Adult; D000368:Aged; D001782:Blood Donors; D002196:Capillaries; D046148:Donor Selection / Q000379:methods*; D005260:Female; D006452:Hemoglobinometry / Q000295:instrumentation / Q000379:methods*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014680:Veins; D055815:Young Adult
chemical_list: D006454:Hemoglobins