Comprehensive precision analysis of the MIZAR 2.0 hemorheometer in EDTA-anticoagulated canine whole blood samples.

Hemorheology, the study of blood flow properties, utilizes the deformability, elasticity, and aggregability of RBCs to assess health and disease. Although promising in human medicine for diagnosing and monitoring various conditions, its clinical utility in dogs remains unexplored. Given that assay validation is paramount for establishing RIs and interpreting hemorheologic data, we characterized the precision of 13 hemorheologic RBC measurands in dogs using a novel hemorheometer (MIZAR; Alcor Scientific). We investigated the influence of precision type (within- and between-run), temperature (room temperature and 4°C), number of repeats (n 8-22), and wavelength of reading (620 and 800 nm) on measurement CVs. We found 3 distinct measurand categories: consistently low CVs, exemplified by optical transmission flow (OTF); consistently high CVs, exemplified by distribution index (DI); and condition-dependent CVs, exemplified by aggregation index (AI). For measurands with consistently high CVs, n had a greater impact on imprecision than any other factor. All other measurands had expected patterns of imprecision, with within-run measurements having the lowest CVs. Interestingly, measurand values did not significantly impact CVs in healthy dogs. For most measurands, CVs varied among samples handled similarly, which could be related to inter-individual variation; this observation may not necessarily affect the clinical accuracy of the hemorheometer in assessing clinically relevant changes in hemorheologic measurands during disease states.