engleski

Monocyte distribution width (MDW) values measured in K2-EDTA and K3-EDTA test tubes

BACKGROUND-AIM: Monocyte Distribution Width (MDW) is a novel hematology parameter, which represents a measure of change inthe monocyte size distribution. Morphological changes of monocytes in sepsis show greater heterogeneity of themonocyte population and thus a higher MDW value. MDW provides significant added value along with currently usedsepsis markers (WBC, PCT, CRP, IL-6) for early sepsis screening. The clinical MDW cut-off of 20.0 was establishedthrough a blinded prospective multi-center pilot study using K2-EDTA venous whole blood samples. According to thisstudy, MDW values >20.0 should raise suspicion that sepsis is present or will develop in patients within twelve hoursof the Emergency Department (ED) presentation. The type of EDTA salt may affect the accuracy of cell counting andsizing. The aim of our study was to evaluate the impact of Beckton-Dickinson (BD) blood collection tubes containingK2-EDTA and K3-EDTA as anticoagulants on MDW values. METHODS: Blood samples from 158 apparently healthy individuals undergoing annual health checkups were collected in K2-EDTA and simultaneously in K3-EDTA test tubes. All samples were analyzed for CBC with differential within 30 minafter collection on a Beckman Coulter Unicel DxH 900 hematology analyzer. Data were tested for normality usingthe Kolmogorov–Smirnov test. The significance of differences between samples was assessed by Wilcoxon's pairedtest. P < 0.05 was considered statistically significant. Data are presented as medians and interquartile ranges. Bland-Altman plotting was performed to assess the comparability of results. Statistical analysis was performed using MedCalc 14.8.1.0 statistical software. RESULTS: The study included 158 participants, age 30 (18–58), 91 (57, 6%) males. For K2-EDTA tubes median MDW value was 16, 25(15, 38–17, 44) and for K3-EDTA tubes 17, 11 (16, 18–18, 42). A statistically significant difference was found comparingMDW values in K2- EDTA and K3-EDTA (P<0.001). Bland-Altman analysis revealed statistically significant constant(mean -0, 8 ; 95%CI -1, 03 to -0, 59) and proportional differences (mean -4, 8% ; 95%CI -6, 10 to -3, 52). Limits of agreement(±1.96 SD of differences) ranged from -3.6 to 1.9 for constant difference and -20, 9 to 11.2% for proportional difference, respectively. Most of the values were lower when measured in K2-EDTA then in K3-EDTA. CONCLUSIONS: K2-EDTA is recommended as the anticoagulant of choice for routine hematology testing by the International Council for Standardization in Hematology (ICSH) and Clinical Laboratory Standard Institute (CLSI). Although K2- EDTA isthe anticoagulant of choice, K3-EDTA tubes are still in widespread use. Our study provides evidence that there is astatistically significant difference between K2-EDTA and K3-EDTA MDW measurements.To accurately use of MDW asadditional marker for early sepsis screening, it is necessary to perform clinical outcome studies based on the impactof K3-EDTA on MDW measurements.

sepsis markers ; MDW ; K2-EDTA ; K3-EDTA

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