Effects of potential confounding variables on accuracy of a commercially available veterinary point-of-care hematocrit meter in the evaluation of blood samples from dogs and cats

OBJECTIVE To assess the agreement in measurements of Hct values and hemoglobin (Hgb) concentrations in blood samples from dogs and cats between a commercially available veterinary point-of-care (POC) Hct meter and a laboratory-based (LAB) analyzer and to determine the effects of various conditions (ie, lipemia, hyperbilirubinemia, hemolysis, autoagglutination, and reticulocytosis) on the accuracy of the POC meter. SAMPLES Blood samples from 86 dogs and 18 cats PROCEDURES Blood samples were run in duplicate on the POC meter, which reported Hgb concentration, measured via optical reflectance, and a calculated Hct value. The POC meter results were compared with results from a LAB analyzer. Blood samples with grossly visible lipemia, icterus, hemolysis, and autoagglutination were noted. RESULTS Mean +/- SD values for LAB Hct were 33.9 +/- 15.73% (range, 3.9% to 75.8%), and for LAB Hgb were 11.2 +/- 5.4 g/dL (range, 1 to 24.6 g/dL). Mean bias between POC Hct and LAB Hct values was -1.8% with 95% limits of agreement (LOAs) of -11.1% to 7.5% and between POC Hgb and LAB Hgb concentrations was - 0.5 g/dL with 95% LOAs of -3.8 to 2.8 g/dL. There was no influence of lipemia (14 samples), icterus (23), autoagglutination (14), hemolysis (12), or high reticulocyte count (15) on the accuracy of the POC meter. The POC meter was unable to read 13 blood samples; 9 had a LAB Hct <= 12%, and 4 had a LAB Hct concentration between 13% and 17%. CONCLUSIONS AND CLINICAL RELEVANCE Overall, measurements from the POC meter had good agreement with those from the LAB analyzer. However, LOAs were fairly wide, indicating that there may be clinically important differences between measurements from the POC meter and LAB analyzer.

Automated summary

The study assessed the agreement in measurements of Hct values and Hgb concentrations in blood samples from dogs and cats between a commercially available veterinary point-of-care (POC) Hct meter and a laboratory-based (LAB) analyzer, showing good agreement between the two. Interestingly, various conditions such as lipemia, hyperbilirubinemia, hemolysis, autoagglutination, and reticulocytosis did not affect the accuracy of the POC meter.