Aim: to test the precision and accuracy of a Digital Microcapillary instrument in measuring blood and plasma viscosity.
Methods: about 40 blood samples were drawn for precision test. The samples were obtained from patients admitted for Medical Check-Up at CiptoMangunkusumo Hospital (RSCM) in December 2011.Accuracy test was evaluated using cross-sectional design and involving 135 patients with acute ischemic stroke. The patients underwent either inpatients or outpatients care at Department of Clinical Pathology, Department of Neurology,and Emergency Unit of RSCM, Fatmawati Hospital Jakarta, Prikasih Hospital Jakarta, and Bhakti Yuda Hospital Depok. The precision test was evaluated by calculating the coefficient of variation (CV), interrater variability of Cronbach Alpha, and reliability coefficient of Bland Altman. The accuracy of the test was evaluated with a diagnostic test. The gold standard used for these tests was Brookfield LV-DV III viscometer.
Results: the results of precision test were: CV = 0.04; interrater variability of blood and plasma viscosity = 0.94 and 0.82, respectively; the Bland Altman mean difference = -0.19. The results of accuracy test were: sensitivity of blood and plasma viscosity measurement were 88.9% and 100%, respectively; specificity of blood and plasma viscosity measurement were 88.9% and 84%, respectively.
Conclusion: the digital microcapillary has high sensitivity and specificity; therefore the instrument can be considered to be used as screening test tool to measure blood and plasma viscosity.