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%.

CONCLUSION:

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: Heather March, Anne Barger, Sheila McCullough, David Schaeffer, Peter Macwilliams
• Journal: Veterinary clinical pathology (Vet Clin Pathol) Vol. 34 Issue 2 Pg. 106-9 (Jun 2005) ISSN: 0275-6382 [Print] United States
• PMID: 15902660 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Hemoglobins

Topics

• Animals
• Dogs (blood)
• Hemoglobinometry (instrumentation, veterinary)
• Hemoglobins (analysis)
• Hemolysis
• Reproducibility of Results
• Sensitivity and Specificity