LAUSR

BACKGROUND Elevated whole blood viscosity (WBV) is associated with increasing blood flow resistance in the microcirculation and is used to predict the occurrence and outcome of cardiovascular diseases. OBJECTIVE We evaluated the analytical performance of the ZL 6000i (Zonci Technology, Beijing, China), new fully automated cone-plate rotational type viscometer. METHODS We collected blood samples from 287 adults to establish a reference range. We evaluated total precision for 20 days using quality control (QC) samples and within-run precision was evaluated by performing 50 consecutive measurements of blood samples. Aliquots of blood samples were stored at room temperature and 5°C to assess the effect of storage time and temperature on viscosity measurement. RESULTS The reference ranges and median values of WBV were significantly higher in males than in females due to difference in hematocrit level. The coefficients of variation (CVs) for precision using QC and human blood samples were <  7.5% at all shear rates. WBV of the samples stored at room temperature for up to 6 h, and at 5°C for samples stored up to 2 days was not different from the control. CONCLUSIONS In this study, the ZL 6000i viscometer yields reproducible WBV data and is clinically useful for monitoring viscosity.