Monocyte Distribution Width as a Diagnostic Marker for Infection: A Systematic Review and Meta-analysis

The Complete Blood Count Sepsis Index Using Monocyte Distribution Width for Early Detection of Sepsis in Patients Without Obvious Signs

OBJECTIVES

Exploiting the complete blood count (CBC) with differential (CBC-diff) for early sepsis detection has practical value for emergency department (ED) care, especially for those without obvious presentations. The objective of this study was to develop the CBC Sepsis Index (CBC-SI) that incorporates monocyte distribution width (MDW) to enhance rapid sepsis screening.

DESIGN

A retrospective observational study.

SETTING

The ED of the University of Kansas Medical Center, United States.

PATIENTS

All adult patients (age 18 or over) presenting to the ED between August 8, 2020, and April 1, 2022, that received a CBC-diff as part of routine clinical care.

INTERVENTIONS

MDW, WBC count, and neutrophil-to-lymphocyte ratio were used to develop a CBC-SI (0 low to 5 high risk) for early sepsis detection. The diagnostic performance of CBC-SI was evaluated for patients with and without obvious early signs of sepsis.

MEASUREMENTS AND MAIN RESULTS

In a cohort of 51,407 ED visits, 1,683 (3.3%) met sepsis criteria; 1,343 (79.8%) septic patients presented with obvious signs and 340 (20.2%) without. The overall area under the curve of the CBC-SI was 0.83 (95% CI, 0.81-0.85). A CBC-SI of greater than or equal to 1 point exhibited a sensitivity of 83.1% (95% CI, 79.9-86.2%) and specificity of 64.8% (95% CI, 64.0-65.5%). Superior performance was observed in the patient subgroup presenting without obvious signs; greater than or equal to 1 point, 81.1% (95% CI, 73.2-88.9%) sensitivity and 69.1% (95% CI, 68.3-69.9%) specificity. Septic patients without obvious signs exhibited delays in antibiotic administration from arrival (median 4.7 vs. 3.4 hr; p < 0.001) and higher rates of ICU admission (43.8% vs. 27.9%; p < 0.001) and in-hospital mortality (14.7% vs. 9.8%; p = 0.011) compared with the septic subgroup presenting with obvious signs.

CONCLUSIONS

The CBC-SI demonstrated strong performance for early sepsis detection. Its performance was best for nonobvious presentations, suggesting highest utility in a subgroup that is most susceptible to delayed interventions and poorer outcomes.

The Need for Standardized Guidelines for the Use of Monocyte Distribution Width (MDW) in the Early Diagnosis of Sepsis

Sepsis is a complex and potentially life-threatening syndrome characterized by an abnormal immune response to an infection, which can lead to organ dysfunction, septic shock, and death. Early diagnosis is crucial to improving prognosis and reducing hospital management costs. This narrative review aims to summarize and evaluate the current literature on the role of monocyte distribution width (MDW) as a diagnostic biomarker for sepsis, highlighting its advantages, limitations, and potential clinical applications. MDW measures the volumetric distribution width of monocytes, reflecting monocytic anisocytosis, and is detected using advanced hematological analyzers. In 2019, it was approved by the FDA as a biomarker for sepsis due to its ability to identify systemic inflammatory response at an early stage. Thirty-one studies analyzed by us have shown that an increased MDW value is associated with a higher risk of sepsis and that its combination with clinical parameters (such as qSOFA) and other biomarkers (CRP, PCT) can enhance diagnostic sensitivity and risk stratification capacity. Despite its high sensitivity, MDW has lower specificity compared to more established biomarkers such as procalcitonin, thus requiring a multimodal integration for an accurate diagnosis. The use of MDW in emergency and intensive care settings represents an opportunity to improve early sepsis diagnosis and critical patient management, particularly when combined with other markers and clinical tools. However, further studies are needed to define a universal cut-off and confirm its validity in different clinical contexts and pathological scenarios.

Monocyte distribution width as a promising biomarker for differential diagnosis of chronic hepatitis, cirrhosis, and hepatocellular carcinoma

Objective

We aimed to investigate the association and diagnostic value of monocyte distribution width (MDW) for chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC).

Methods

MDW levels were measured in 483 individuals (103 CHB, 77 LC, 153 HCC, and 150 controls). MDW was detected using UniCel Dx900 for specific cell volume parameters and the distribution of cell volumes.

Results

Our findings revealed a dynamic upward change in MDW levels across different stages of chronic liver disease, from CHB to LC and HCC. In CHB, MDW levels were highest among HBeAg-positive CHB patients and exhibited a negative correlation with HBV markers while positively correlating with ALT levels. In LC, MDW showed a positive association with the pathological progression of LC, demonstrating consistency with CP scores. MDW proved to be equally effective as traditional detection for diagnosing LC. In HCC, MDW was positively correlated with HCC occurrence and development, with higher levels observed in the high MDW group, which also exhibited elevated AFP levels, MELD scores, and 90-day mortality rates. MDW surpassed predictive models in its effectiveness for diagnosing HCC, as well as CHB and LC, with respective areas under the curve of 0.882, 0.978, and 0.973. Furthermore, MDW emerged as an independent predictor of HCC.

Conclusion

MDW holds significant diagnostic efficacy in identifying CHB, LC, and HCC. These findings suggest that MDW could serve as a promising biomarker for predicting the severity of liver diseases and aid in rational clinical treatment strategies.

Understanding the value of monocyte distribution width (MDW) in acutely ill medical patients presenting to the emergency department: a prospective single center evaluation

The monocyte distribution width (MDW) has emerged as a promising biomarker for accurate and early identification of patients with potentially life-threatening infections. Here we tested the diagnostic performance of MDW in adult patients requiring hospital admission for community-acquired infections and sepsis, evaluated sources of heterogeneity in the estimates of diagnostic accuracy, and assessed the meaning of MDW in a patient population presenting to the emergency department (ED) for acute non-infectious conditions. 1925 consecutive patients were categorized into three groups: non-infection (n = 1507), infection (n = 316), and sepsis/septic shock (n = 102). Diagnostic performance for infection or sepsis of MDW alone or in combination with components of SOFA was tested using AUC of ROC curves, sensitivity, and specificity. The relationship between MDW and different pathogens as well as the impact of non-infectious conditions on MDW values were explored. For the prediction of infection, the AUC/ROC of MDW (0.84) was nearly overlapping that of procalcitonin (0.83), and C-reactive protein (0.89). Statistical optimal cut-off value for MDW was 21 for predicting infection (sensitivity 73%, specificity 82%) and 22 for predicting sepsis (sensitivity 79%, specificity 83%). The best threshold to rule out infection was MDW ≤ 17 (NPV 96.9, 95% CI 88.3-100.0), and ≤ 18 (NPV 99.5, 95% CI 98.3-100.0) to rule out sepsis. The combination of MDW with markers of organ dysfunction (creatinine, bilirubin, platelets) substantially improved the AUC (0.96 (95% CI 0.94-0.97); specificity and sensitivity of 88% and 94%, respectively). In conclusion, MDW has a good diagnostic performance in diagnosing infection and sepsis in patients presenting in ED. Its use as an infection marker even increases when combined with other markers of organ dysfunction. Understanding the impact of interactions of non-infectious conditions and comorbidities on MDW and its diagnostic accuracy requires further elucidation.

Clinical usefulness of presepsin and monocyte distribution width (MDW) kinetic for predicting mortality in critically ill patients in intensive care unit

Background

In this study, we explored the accuracy of two new sepsis biomarkers, monocyte distribution width (MDW) and presepsin (PSP), compared to traditional ones, C-reactive protein (CRP) and Procalcitonin (PCT), to identify sepsis and predict intra-hospital mortality by analyzing their kinetic at different time points during hospitalization stay.

Methods

We enrolled 104 patients admitted to the intensive care unit (ICU) of University Hospital "Paolo Giaccone", Palermo. Among these, 30 (29%) had a clinical diagnosis of sepsis. MDW, PCT, CRP, and PSP were evaluated at admission (T0), after 24 h (T24), 48 h (T48), 72 h (T72), at day 5 (T5), and at discharge (TD).

Results

Patients with sepsis displayed higher levels of PCT and PSP than patients without sepsis at each timepoint; differently, CRP displayed statistically significant differences only at T0, while MDW only at T0 and T24. Patients with increasing levels of PSP displayed lower median survival time than patients with decreasing levels; differences reached statistical significance only at 48 h (20 vs. 29 days, log rank test, p = 0.046). Interestingly, PSP was an independent predictor of ICU mortality at 48 and 72 h after hospital admission. Also, the kinetic of PSP had prognostic value, with increased values at 48 h after admission being associated with reduced survival.

Conclusion

Our findings support the role of PSP and its kinetic as a predictor of ICU mortality.

Monocyte distribution width as an early predictor of short-term outcome in adult patients with sepsis

OBJECTIVES

Monocyte distribution width (MDW) is a quantitative measurement of monocyte anisocytosis and has been proposed as an efficient marker for early sepsis detection. This study aimed to assess the prognostic potential of MDW in septic patients.

METHODS

In this study, a total of 252 adult septic patients were enrolled. Demographic, clinical, and laboratory finding including MDW and traditional inflammatory biomarkers detected at three time points (day 1, day 3 and day 6) after admission were collected and compared between 28-day survivors and non-survivors. Receiver operating characteristic (ROC) curves, Kaplan-Meier survival curve and Cox regression analyses were performed to assess and compare their predictive values. Group-based trajectory modeling was applied to identify MDW trajectory endotypes. Basic characteristics and 28-day outcomes were compared between the trajectories.

RESULTS

ROC curve analysis showed that MDW levels measured on day 3 after admission (D3-MDW) had moderate prognostic value and was independently associated with 28-day mortality in patients with sepsis. A D3-MDW value of 26.20 allowed discrimination between survivors and non-survivors with a sensitivity of 77.8 % and a specificity of 67.6 %. However, the prognostic accuracy of D3-MDW was diminished in immune-compromised patients and patients who already received antibiotics before admission. Group-based trajectory modeling indicated that excessively elevated and delayed decreased MDW levels during the first week after admission inversely correlated with prognosis.

CONCLUSIONS

MDW values detected on day 3 after admission and its kinetic change might be potential markers for predicting short-term outcome in adult septic patients.

Surviving Sepsis Campaign Research Priorities 2023

OBJECTIVES

To identify research priorities in the management, epidemiology, outcome, and pathophysiology of sepsis and septic shock.

DESIGN

Shortly after publication of the most recent Surviving Sepsis Campaign Guidelines, the Surviving Sepsis Research Committee, a multiprofessional group of 16 international experts representing the European Society of Intensive Care Medicine and the Society of Critical Care Medicine, convened virtually and iteratively developed the article and recommendations, which represents an update from the 2018 Surviving Sepsis Campaign Research Priorities.

METHODS

Each task force member submitted five research questions on any sepsis-related subject. Committee members then independently ranked their top three priorities from the list generated. The highest rated clinical and basic science questions were developed into the current article.

RESULTS

A total of 81 questions were submitted. After merging similar questions, there were 34 clinical and ten basic science research questions submitted for voting. The five top clinical priorities were as follows: 1) what is the best strategy for screening and identification of patients with sepsis, and can predictive modeling assist in real-time recognition of sepsis? 2) what causes organ injury and dysfunction in sepsis, how should it be defined, and how can it be detected? 3) how should fluid resuscitation be individualized initially and beyond? 4) what is the best vasopressor approach for treating the different phases of septic shock? and 5) can a personalized/precision medicine approach identify optimal therapies to improve patient outcomes? The five top basic science priorities were as follows: 1) How can we improve animal models so that they more closely resemble sepsis in humans? 2) What outcome variables maximize correlations between human sepsis and animal models and are therefore most appropriate to use in both? 3) How does sepsis affect the brain, and how do sepsis-induced brain alterations contribute to organ dysfunction? How does sepsis affect interactions between neural, endocrine, and immune systems? 4) How does the microbiome affect sepsis pathobiology? 5) How do genetics and epigenetics influence the development of sepsis, the course of sepsis and the response to treatments for sepsis?

CONCLUSIONS

Knowledge advances in multiple clinical domains have been incorporated in progressive iterations of the Surviving Sepsis Campaign guidelines, allowing for evidence-based recommendations for short- and long-term management of sepsis. However, the strength of existing evidence is modest with significant knowledge gaps and mortality from sepsis remains high. The priorities identified represent a roadmap for research in sepsis and septic shock.

Can Haematological Parameters Discriminate COVID-19 from Influenza?

Symptoms of COVID-19 are similar to the influenza virus, but because treatments and prognoses are different, it is important to accurately and rapidly differentiate these diseases. The aim of this study was to evaluate whether the analysis of complete blood count (CBC), including cellular population (CPD) data of leukocytes and automated flow cytometry analysis, could discriminate these pathologies. In total, 350 patients with COVID-19 and 102 patients with influenza were included between September 2021 and April 2022 in the tertiary hospital of Suresnes (France). Platelets were lower in patients with influenza than in patients with COVID-19, whereas the CD16pos monocyte count and the ratio of the CD16pos monocytes/total monocyte count were higher. Significant differences were observed for 9/56 CPD of COVID-19 and flu patients. A logistic regression model with 17 parameters, including among them 11 CPD, the haemoglobin level, the haematocrit, the red cell distribution width, and B-lymphocyte and CD16pos monocyte levels, discriminates COVID-19 patients from flu patients. The sensitivity and efficiency of the model were 96.2 and 86.6%, respectively, with an area under the curve of 0.862. Classical parameters of CBC are very similar among the three infections, but CPD, CD16pos monocytes, and B-lymphocyte levels can discriminate patients with COVID-19.

Management of Sepsis and Septic Shock: What Have We Learned in the Last Two Decades?

Sepsis is a clinical syndrome encompassing physiologic and biological abnormalities caused by a dysregulated host response to infection. Sepsis progression into septic shock is associated with a dramatic increase in mortality, hence the importance of early identification and treatment. Over the last two decades, the definition of sepsis has evolved to improve early sepsis recognition and screening, standardize the terms used to describe sepsis and highlight its association with organ dysfunction and higher mortality. The early 2000s witnessed the birth of early goal-directed therapy (EGDT), which showed a dramatic reduction in mortality leading to its wide adoption, and the surviving sepsis campaign (SSC), which has been instrumental in developing and updating sepsis guidelines over the last 20 years. Outside of early fluid resuscitation and antibiotic therapy, sepsis management has transitioned to a less aggressive approach over the last few years, shying away from routine mixed venous oxygen saturation and central venous pressure monitoring and excessive fluids resuscitation, inotropes use, and red blood cell transfusions. Peripheral vasopressor use was deemed safe and is rising, and resuscitation with balanced crystalloids and a restrictive fluid strategy was explored. This review will address some of sepsis management's most important yet controversial components and summarize the available evidence from the last two decades.

Monocyte distribution width (MDW) in sepsis

Sepsis is a life-threatening syndrome due to a dysregulated host response to infection, which can be caused by bacterial, viral, or fungal infection. Thus, it is crucial to know how the different microorganisms influence the levels of a biomarker. In the last decade, monocyte distribution width (MDW) has emerged as a promising sepsis biomarker, especially in acute settings, such as the Emergency Department and Intensive Care Unit. In this article, we explore the relationship between MDW and the different pathogens causing infection. Noteworthy, MDW is not a biological molecule, but it is calculated by a mathematical formula based on monocyte characteristics. Monocytes represent the first line defence against microorganisms and undergo activation upon infection, independently from the invading pathogen. According to the knowledge on the biomarker biology and the few literatures evidence, MDW may be considered a biomarker of sepsis, independent of the causative pathogen. However, further investigations are warranted before drawing definite conclusion.

Effects of Different Types of Recombinant SARS-CoV-2 Spike Protein on Circulating Monocytes' Structure

This study investigated the biological effects on circulating monocytes after challenge with SARS-CoV-2 recombinant spike protein. Whole blood collected from seven ostensibly healthy healthcare workers was incubated for 15 min with 2 and 20 ng/mL final concentration of recombinant spike protein of Ancestral, Alpha, Delta, and Omicron variants. Samples were analyzed with Sysmex XN and DI-60 analyzers. Cellular complexity (i.e., the presence of granules, vacuoles and other cytoplasmic inclusions) increased in all samples challenged with the recombinant spike protein of the Ancestral, Alpha, and Delta variants, but not in those containing Omicron. The cellular content of nucleic acids was constantly decreased in most samples, achieving statistical significance in those containing 20 ng/mL of Alpha and Delta recombinant spike proteins. The heterogeneity of monocyte volumes significantly increased in all samples, achieving statistical significance in those containing 20 ng/mL of recombinant spike protein of the Ancestral, Alpha and Delta variants. The monocyte morphological abnormalities after spike protein challenge included dysmorphia, granulation, intense vacuolization, platelet phagocytosis, development of aberrant nuclei, and cytoplasmic extrusions. The SARS-CoV-2 spike protein triggers important monocyte morphological abnormalities, more evident in cells challenged with recombinant spike protein of the more clinically severe Alpha and Delta variants.