Gregory Eisinger, BA, MD, MSW
fellow
Ohio State University Hospital
Columbus, Ohio
Disclosure information not submitted.
Wissam Osman, BS
Research Assistant
The Ohio State University, United States
Disclosure information not submitted.
Evan Prather, BS
Research Assistant
Ohio State University, Ohio, United States
Disclosure information not submitted.
Mark Julian, MS
Senior Research Associate
The Ohio State University, United States
Disclosure information not submitted.
Mikhail Gavrilin, PhD
Research scientist
The Ohio State University, United States
Disclosure information not submitted.
Elliott Crouser, MD
Professor of Medicine
The Ohio State University
Columbus, Ohio, United States
Disclosure information not submitted.
Mark Wewers, MD
Professor of Medicine
The Ohio State University, United States
Disclosure information not submitted.
Title: Blood Collection in Heparin Yields Higher Values for Monocyte Distribution Width Versus EDTA
Introduction: Monocyte distribution width (MDW) has become an important biomarker for early sepsis detection in recent years. Prior work has consistently demonstrated a higher reference range for samples collected in K3 versus K2 EDTA tubes. In prior in vitro inflammasome activation experiments, EDTA has been shown to cause suppression of IL1ß levels, an important marker of inflammasome activity. As such, we conducted a series of in vitro blood experiments using heparin as the anticoagulant to examine the impact on the reference range for MDW and the LPS effect on both MDW and IL1ß release.
Methods: Whole blood was collected from healthy volunteers (n=8) in either K2 EDTA or heparin sodium (HS) vacutainer tubes. Measurements of MDW were completed using the Unicel DxH900 analyzer (Beckman Coulter) at baseline and after 4-hour incubation with or without bacterial endotoxin (LPS) at a concentration of 1 µg/mL. Plasma was then collected for IL1ß measurement by sandwich ELISA.
Results: There were no differences in baseline MDW values between HS and EDTA tubes. After a 4-hour incubation without LPS, median MDW values were significantly higher in the heparinized samples (21.3) compared to EDTA (16.1; p=0.0006). A similar magnitude of effect was seen after a 4-hour incubation with LPS (30 vs 24.6; p=0.0024), with higher than baseline values in both groups reflecting inflammasome activation as is seen in patients with sepsis. The increased values for MDW in untreated samples in HS at 4 hours were not associated with IL1ß release. All samples treated with LPS showed significant IL1ß release reflecting inflammasome activation. Median levels of IL1ß tended to be higher in HS compared to EDTA, though with significant variability preventing the data from reaching statistical significance given the small sample size (2.78 [IQR 1.66 – 5.32] vs 1.79 [IQR 0.98 – 2.37] ng/mL; p=0.23).
Conclusions: The use of HS compared to EDTA as an anticoagulant for blood collection results in higher MDW values at 4 hours both with and without stimulation by LPS. The effect of time alone on MDW in heparinized samples did not appear to be inflammasome-dependent. Compared to K3 EDTA (on average 2 points higher than K2 EDTA), the effect of heparin on MDW appears to even more pronounced and also time-dependent, an effect not seen with K3 EDTA.