Successful utilization of point-of-care testing (POCT) requires correlation between POCT and core laboratory values. Validation studies, including assessment of linearity and bias, precision, stability, and effectiveness as a blind check sample, establish this relationship. Traditionally, human blood has been used as the substrate for validation and proficiency materials. However, acquisition of human blood has become problematic because of increased costs of blood products and the need for institutional approval. In this study, the authors hypothesized that animal blood may provide a suitable alternative for POCT validation. They performed linearity studies on Accu-Chek Advantage glucose meters (Roche Diagnostics, Indianapolis, IN) and HemoCue B-Hemoglobin analyzers (HemoCue Inc., Lake Forest, CA) using bovine, horse, sheep, and swine blood. Using animal blood, the instruments demonstrated a linear response with close correlation to human blood. Precision calculations (human blood, n = 20; animal blood, n = 14) for HemoCue results yielded coefficients of variation between 0.5% and 2.6%. Glucose values (human blood, n = 17–20; animal blood, n = 15–20) had coefficients of variation between 2.5% and 3.9%. Using human and animal blood, blind check samples with concentrations of approximately 50 mg/dL and 175 mg/dL showed from −3.0 to 4.0 mg/dL bias for the low sample and −5.1 to 0.6% bias for the high sample between hospital unit and laboratory reference meters. Examination of hemolysis with repeated washes showed that bovine blood was the most stable of the animal blood, correlating with human blood values. Based on stability and handing characteristics, bovine blood seems to be ideally suited for POCT validation studies.
From the Johns Hopkins Medical Institutions, Baltimore, MD (B. Silverman, Dr Clarke, K. Dyer, J. Stem, and Dr Sokoll), and Baystate Health Systems, Springfield, MA (Dr Nichols).
Reprints: Lori J. Sokoll, PhD, Department of Pathology, 600 N. Wolfe Street, Meyer B125, Baltimore, MD 21287 (e-mail: firstname.lastname@example.org).