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Capillary vs venous blood: delayed measurement of hemoglobin concentrations and hematocrit
Author(s) -
Drammeh Bakary S,
Mandava Usha,
Zhang Mindy,
Schleicher Rosemary L,
Pfeiffer Christine M
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.538.7
Subject(s) - vacutainer , hematocrit , hemoglobin , medicine , venous blood , anemia , blood volume , anesthesia
The influence of preanalytical factors on hemoglobin (Hb) concentrations and hematocrit (Hct) is important in anemia assessment particularly in field settings where sample handling might be compromised. We collected venous (Vacutainer®) and capillary (2 nd , 3 rd , 4 th drops followed by Microtainer®) blood from 35 adults and measured Hb and Hct using a HemoCue Hb‐201 and Block Scientific Inc. centrifuge, respectively. Blood (Vacutainer and Microtainer) was stored at 10°C for up to 3 days (n=15); Microtainer blood was also stored at −70°C for 4 days (n=32). We calculated mean changes against appropriate comparator groups and performed ANOVA and t‐tests using SAS software (p<0.05). There were no significant differences in mean (±SE) Hb concentrations (g/dL) between Vacutainer (14.4±0.3) and Microtainer (14.2±0.2) blood, nor among 2 nd , 3 rd and 4 th capillary drops (14.7±0.2). We saw significant Hb differences between Microtainer blood and individual drops (p<0.0001). Delays for up to 3 days did not affect Hb and Hct measurements (<2% change) if blood was kept cool. Freezing blood for 4 days did not affect Hb concentrations either (≤2% change). Due to small differences in Hb between capillary drops and Vacutainer or Microtainer blood (<4%), it is preferable to measure capillary blood Hb from the Microtainer. Unexpected delays in testing or accidental freezing of blood do not rule out valid results for anemia assessment.