agreement between whole-blood crp measurement using humacount 5dcrp and serum crp measurement by immunoturbidimetry (abbott alinity ci series): a comparative study

C-reactive protein (crp), an acute-phase protein in response to infection, inflammation, and tissue damage, is useful for both diagnosis and monitoring. nowadays, serum crp with immunoturbidimetry is a popular method for measuring crp. this method requires more time for preparation and larger sample volumes. humacount 5dcrp, a hematology analyzer, offers faster, single-run complete blood count and crp tests, reducing turn-around-time (tat). however, this new method should be validated and compared with the established method. the objective of this study was to evaluate the agreement between whole-blood humacount 5dcrp and serum crp level and immunoturbidimetry method (abbott alinity). the crp levels of 65 patients were each examined using whole-blood samples in humacount 5dcrp and serum samples in abbott alinity.  the correlation of crp values was evaluated using spearman test. the reliability test used cohen kappa agreement coefficient. bland-altman curve test analysis was used to examine the difference in limit of agreement of crp levels between those analyzers. spearman test showed a very strong positive correlation (r=0.956, p<0.001). kappa agreement test analysis revealed almost perfect agreement (r = 0.938, p < 0.001). bland-altman curve analysis showed a mean difference of -2.59 (95% ci -12.34 - 7.16), where of the 65 samples tested, only four samples had a difference in crp levels outside the limit of agreement value. the whole blood crp with humacount 5dcrp is strongly agreed with crp with abbott alinity. it can serve as a reliable crp testing, provide rapid results to support faster clinical decision-making, and improve patient management.