Derivation of a Single-Panel Lab Test that Includes MDW to Create a Universal Sepsis Screening Tool


Globally, sepsis and septic shock affect millions of patients.1 And while it is known that early identification and early treatment (e.g., intravenous fluids and antibiotics) result in lower mortality rates and better overall outcomes,2 identifying sepsis from its early vague signs and symptoms is challenging at best.3

Having a reliable sepsis biomarker may assist clinicians in identifying sepsis faster and in knowing which tests to order to get antibiotics to patients faster and save lives. The objective of this retrospective study was to determine the association between Monocyte Distribution Width (MDW) used in practice and time to antibiotics. Of the more than 90,000 patients who visited the ED during the study period, 1,736 of them received a complete blood count with differential (CBC-Diff) including MDW within 3 h of arrival and met Sepsis-3 criteria3 within 72 h of arrival.

Patients were divided into three groups:

  1. Those with high suspicion of sepsis (abnormal vitals AND elevated lactate; n=338)
  2. Those with low suspicion of sepsis (abnormal vitals OR elevated lactate; n=1012)
  3. Those with no suspicion of sepsis (no vital sign indicators and normal or no lactate; n=386)

The time from ED arrival to antibiotic order was compared for patients with MDW values grouped as normal (0–20 U), elevated (20.1–24.9 U), and high (>25 U).

The study found:

  • Regardless of MDW value, on average, patients in the high suspicion group received antibiotics 50% faster than those with occult symptoms (2.25 h v 3.63 h, respectively)
  • Within the low suspicion group, time to antibiotics for patients with high MDW was ~30 minutes faster than that for those with normal MDW
  • Within the no suspicion, occult sepsis group, time to antibiotics for patients with high MDW was ~60 minutes faster than that for those with normal MDW. For patients with elevated MDW, time to antibiotics was ~30 minutes faster

Conclusion: Increases in MDW above normal were associated with a decrease in time from arrival to antibiotic order in septic patients with low or no suspicion at ED presentation. Providing clinicians with MDW results as part of the patient assessment on a routine CBC-Diff may serve as an important early indicator, especially for septic patients with atypical presentations, to decrease time to antibiotics.

At a Glance


Patients met study criteria for
SEP-3, CBC, and MDW

50 %

Higher time to antibiotics for patients with occult symptoms

1 h

Decrease in time to antibiotics for occult sepsis patients with high MDW

Read Society of Academic Emergency Medicine (SAEM) poster here

Learn more about MDW

1. Sepsis. World Health Organization (WHO). 2023. Accessed March 9, 2023.

2. Dellinger RP, Levy MM, Rhodes A, et al. Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012. Crit Care Med. 2013;41(2):580-637. doi:10.1097/CCM.0b013e31827e83af

3. Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801-810. doi:10.1001/jama.2016.0287