Unlocking the CBC with MDW: A Global, Single-
panel Lab Sepsis Screening Tool




The Complete Blood Count with Differential (CBC-Diff) is a first line laboratory test ordered in the Emergency Department.1 The CBC-Diff report is generated by an automated hematology analyzer and provides insights about the immune system through various leukocyte parameters. Further information can be gleaned by considering leukocyte parameters in relationship to each other. For example, the ratio of neutrophils to lymphocytes can suggest a dysregulated immune response.

Understanding the synergies of the differential parameters may provide valuable diagnostic information at no additional cost and with no additional time.


In this single-center retrospective study, scientists analyzed vital signs and lab results from over 50,000 Emergency Department patients to create a simple 5-point sepsis screening tool, the CBC Index, to reliably estimate the likelihood that a patient will develop sepsis.

Logistic regression identified four differential parameters (white blood cell, lymphocyte and neutrophil counts, and Monocyte Distribution Width) that, when considered together, significantly increased early sepsis diagnostic performance. WBC count elevation is associated with host response to infection but as a standalone parameter, has limited utility for sepsis screening due to low specificity and sensitivity. The Neutrophil to Lymphocyte Ratio (NLR) is known to increase with physiological stresses, including those experienced during sepsis. Moreover, sepsis can stimulate apoptosis (programmed cell death) in lymphocytes2,3 and thus cause the NLR to increase. More recently, MDW, a measure of the morphological changes associated with monocyte activation, has emerged as an integral component of the CBC for early identification of sepsis.4,5

An index score was derived from patient data and applied to a validation cohort that included patients without sepsis, with overt sepsis presentation, and with occult sepsis presentation.

The study found:

  • The composite CBC Index, a combination of WBC count, MDW, and NLR, showed superior diagnostic performance in early sepsis detection over any single parameter, especially in the occult group
  • There was a linear relationship between the CBC infection severity index and likelihood that a patient would develop sepsis or septic shock

At a Glance


Adult ED patients receiving a CBC studied


-point system for scoring the likelihood of sepsis development


-fold increase in odds of sepsis event with each point increase of the CBC Index Score


Read the AACC poster here Click here

Learn more about MDW

1. Vidyarthi AR, Hamill T, Green AL, Rosenbluth G, Baron RB. Changing Resident Test Ordering Behavior: A Multilevel Intervention to Decrease Laboratory Utilization at an Academic Medical Center. Am J Med Qual. 2015;30(1):81-87. doi:10.1177/1062860613517502

2. Drăgoescu AN, Pădureanu V, Stănculescu AD, et al. Neutrophil to Lymphocyte Ratio (NLR)-A Useful Tool for the Prognosis of Sepsis in the ICU. Biomedicines. 2021;10(1). doi:10.3390/biomedicines10010075

3. Schupp T, Weidner K, Rusnak J, et al. The Neutrophil-to-Lymphocyte-Ratio as Diagnostic and Prognostic Tool in Sepsis and Septic Shock. Clin Lab. 2023;69(5). doi:10.7754/Clin.Lab.2022.220812

4. Crouser ED, Parrillo JE, Seymour C, et al. Improved Early Detection of Sepsis in the ED with a Novel Monocyte Distribution Width Biomarker. Chest. 2017;152(3):518-526. doi:10.1016/j.chest.2017.05.039

5. Crouser ED, Parrillo JE, Martin GS, et al. Monocyte Distribution Width Enhances Early Sepsis Detection in the Emergency Department Beyond SIRS and qSOFA. J Intensive Care. 2020;8:33. doi:10.1186/s40560-020-00446-3