title: Use of the ADVIA 120 for differentiating extracellular and intracellular hemoglobin.
abstract: BACKGROUND
  The use of cell-free hemoglobin (Hgb) solutions, such as Oxyglobin (Biopure Corp, Cambridge, MA, USA), as a blood substitute for the treatment of acute anemias is increasing in veterinary medicine. These solutions interfere with colorimetric tests, which do not discriminate between cellular Hgb (Hgb-cell) from the patient and extracellular Hgb (Hgb-delta) from the Oxyglobin, and therefore make the monitoring of anemia, based on Hgb concentration, difficult. The ADVIA 120 hematology analyzer (Bayer Diagnostics, Tarrytown, NY, USA) evaluates Hgb by 2 methods, a standard cyanmethemoglobin colorimetric method and flow cytometry, and therefore might provide the means to differentiate extracellular and intracellular Hgb.
  
  
  OBJECTIVE
  The objective of this study was to determine the accuracy and precision of the ADVIA 120 in differentiating extracellular from intracellular Hgb.
  
  
  METHODS
  Anticoagulated whole blood samples from 10 healthy dogs were analyzed in triplicate on the ADVIA 120. Hgb-delta concentration was determined by adding Oxyglobin (13 g/dL) to the whole blood samples at dilutions of 1:1, 1:2, 1:4, 1:8, 1:16, and 1:32. Hgb-cell and Hgb-total values were calculated and compared with actual values by linear regression. Analyses were done in triplicate and repeated 9 consecutive times to evaluate intra-assay precision of Hgb-total and Hgb-cell determinations.
  
  
  RESULTS
  Correlation between Hgb values obtained by colorimetric (Hb-total) and flow cytometric (Hgb-cell) methods on whole blood samples was high (R(2) = .99; n = 10) with a slope of 0.96 and intercept of 0. Correlation between actual and predicted Hgb-cell values also was high (R(2) = .99), with a small positive bias (0.289 +/- 0.185; n = 60). Intra-assay precisions were high, with most coefficients of variation <2%.
  
  
  CONCLUSIONS
  The ADVIA 120 is capable of differentiating Hgb-cell from Hgb-delta. The flow cytometric method is accurate and precise when compared with the cyanmethemoglobin method. A small bias between the results is unlikely to be clinically significant but may affect the ability of the ADVIA to differentiate small quantities (<0.3 g/dL) of Hgb-delta.
authors.affiliation: Department of Veterinary Clinical Medicine, University of Illinois, Urbana, IL, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: March
authors.forename: Anne
authors.initials: A
authors.lastname: Barger
authors.forename: Sheila
authors.initials: S
authors.lastname: McCullough
authors.forename: David
authors.initials: D
authors.lastname: Schaeffer
authors.forename: Peter
authors.initials: P
authors.lastname: Macwilliams
mesh_terms: D000818:Animals; D004285:Dogs / Q000097:blood*; D006452:Hemoglobinometry / Q000295:instrumentation* / Q000662:veterinary; D006454:Hemoglobins / Q000032:analysis*; D006461:Hemolysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D006454:Hemoglobins