Monocyte Distribution Width

Severity of infection biomarker

Monocyte Distribution Width (MDW),  proprietary to Beckman Coulter analyzers, is the only regulatory-cleared hematological biomarker that helps to establish severity of infection and risk of sepsis in adult patients in the emergency department. MDW is a measure of increased morphological variability of monocytes in response to bacterial, viral or fungal infections.

MDW is reported automatically as part of a routine CBC with Differential test on the DxH 900 and DxH 690T hematology analyzers using the Early Sepsis Indicator (ESId) application*, which enables automatic reporting with no workflow changes or need to order an additional test.

This product may not be available in your country or region at this time. Please contact your Beckman Coulter sales representative or distributor for more information.


MDW, proprietary to Beckman Coulter analyzers, is the only regulatory-cleared hematological biomarker that helps to establish severity of infection and risk of sepsis in adult patients in the ED.

Available Early

MDW helps reduce diagnostic uncertainty. It is available early to help clinicians escalate or de-escalate care in patients with suspected infectious etiology.

CBC Diff

MDW is available early in patient assessments as part of CBC with Differential tests—no need to order additional tests.

By including MDW in our thought process, we can potentially uncover an underlying sepsis that could have been otherwise missed, especially when other causes can explain a patient’s symptoms.
Nima Sarani, M.D.
University of Kansas Medical Center


Navigating the uncertainties of sepsis and severe infection is challenging. In this short training video, Dr. Tobin Efferen shares the fundamentals of MDW and explains the clinical utility of incorporating the MDW biomarker as part of the CBC-diff early in ED screening to aid in identifying severity of infection and risk of sepsis.

MDW Patient Case Studies

MDW has been studied for the past decade with more than 16 peer-review publications and over 21,000+ patients6-16, confirming the robustness and reproducibility of MDW performance in different patient populations. Learn more about MDW by reviewing the patient case studies below.


Additional resources

BLOG What is Monocyte Distribution Width?

A large unmet clinical need for the early detection of sepsis exists. MDW is a novel, FDA-cleared biomarker intended to meet this need.

Sepsis detection in the emergency department

Peer-Reviewed Clinical Study MDW Improves SIRS and qSOFA Early Sepsis Detection in the Emergency Department

New analysis from a pivotal study shows that patients with abnormal MDW values at presentation have increased odds of sepsis.

Emergency department physician

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  1. S. Fernando et al., Emergency Department Disposition Decisions and Associated Mortality and Costs in ICU Patients with Suspected Infection, Crit Care 2018; 22,172.
  2. E. Rivers et al., Early and Innovative Interventions for Severe Sepsis and Septic Shock: Taking Advantage of a Window of Opportunity, CMAJ 2005; 173(9):1054-65. 
  3. A. Vijayan et al., Procalcitonin: A Promising Diagnostic Marker for Sepsis and Antibiotic Therapy, Journal of Intensive Care 2017; 5:51.
  4. M. Filbin et al., Presenting Symptoms Independently Predict Mortality in Septic Shock: Importance of a Previously Unmeasured Confounder, Critical Care Medicine 2018; 46(10), 1592-1599. 
  5. UniCel DxH 900 Coulter Cellular Analysis System Early Sepsis Indicator (ESId) Application Addendum PN C42014AC April 2020
  6. E. Piva et al., Monocyte Distribution Width (MDW) Parameter as a Sepsis Indicator in Intensive Care Units, Clin Chem Lab Med 2021. 
  7. P. Hausfater et al., Monocyte Distribution Width (MDW) Performance as an Early Sepsis Indicator in the Emergency Department: Comparison with CRP and Procalcitonin in a Multicenter International European Prospective Study, Crit Care 2021; 25, 227. 
  8. A. Woo et al., Monocyte Distribution Width Compared with C-Reactive Protein and Procalcitonin for Early Sepsis Detection in the Emergency Department, PLoS ONE 2021; 16(4): e0250101. 
  9. H. Lin et al., Clinical Impact of Monocyte Distribution Width and Neutrophil-to-Lymphocyte Ratio for Distinguishing COVID-19 and Influenza from Other Upper Respiratory Tract Infections: A Pilot Study, PLoS ONE 2020 15(11): e0241262.
  10. L. Agnello et al., Monocyte Distribution Width (MDW) as a Screening Tool for Sepsis in the Emergency Department, Clin Chem Lab Med 2020; 58(11):1951-1957. https://doi:10.1515/cclm-2020-0417
  11.  G. Riva et al., Monocyte Distribution Width (MDW) as Novel Inflammatory Marker with Prognostic Significance in COVID‑19 Patients, Scientific Report 2021; 11:12716. 
  12. Marcos-Morales, A et al., Elevated monocyte distribution width in trauma: An early cellular biomarker of organ dysfunction, Injury 2021; S0020-1383(21):00933-00935. 
  13. E. Crouser et al., Monocyte Distribution Width: A Novel Indicator of Sepsis-2 and Sepsis-3 in High-Risk Emergency Department Patients, Critical Care Med 2019; 47:1018-1025.
  14. E. Crouser et al., Improved Early Detection of Sepsis in the ED with a Novel Monocyte Distribution Width Biomarker, CHEST 2017; 152(3):518-526.
  15. A. Ognibene et al., Elevated Monocyte Distribution Width in COVID-19 Patients: The Contribution of the Novel Sepsis Indicator, Clinica Chimica Acta 2020; 509: 22-24.
  16. Malinovska, A et al., Monocyte distribution width as part of a broad pragmatic sepsis screen in the emergency department. JACEP Open. 2022; 3:e12679.