As many of our users have likely already noticed, our Sepsis app now has a sponsor and we’re very happy about it! Beckman Coulter has generously agreed to support our continued sepsis education efforts, and we want to take this opportunity to welcome them to the ESCAVO community and introduce the company to our users.
To some of you who may not be familiar with Beckman Coulter, the company is one of the true pioneers in the field of hematology diagnostics. If you have ever had or ordered a complete blood count (CBC), and who hasn’t, you have benefited from its inventions. The company’s founder, Wallace H. Coulter, invented the method used to count and characterize blood cells on a large scale in 1947. This method came to be known as the Coulter Principle and is now used in almost every modern blood analyzer. If you want to learn more about the company’s history, the Coulter Principle and Coulter’s extraordinary scientific and entrepreneurial achievements, have a read here, it’s a great story.
Beckman Coulter has been actively investigating how changes in white blood cells (WBCs) during infection may serve as a harbinger of sepsis. Recently, the company announced the European CE Mark of a new hematology-based test known as Early Sepsis Indicator (ESI) which will be offered as part of routine CBCs with differential in the company’s latest analyzer, the DxH 900. The test was approved for use in the emergency department setting, and given that most patients with sepsis first present with their symptoms in the ER, it could serve as an effective early warning system, significantly speeding up diagnosis and treatment response time, which as we know is the key to a good outcome in sepsis.
So what is ESI? As most clinicians know, WBCs change in significant ways during inflammatory and infectious states. Not only do they greatly increase in number, but their cell sizes and shapes change, their nuclear shape may change as immune genes activate and the chromatin rearranges, numerous granules develop and fill with cytokines and other inflammatory molecules giving the cells a very different appearance, and different receptors appear on the cell membrane to amplify immune signals from other cells.
One example of such a morphological change is the appearance of band cells, or immature polys, in infections. A high number of band cells is an indicator that sepsis may be on the horizon, which is why bands are part of the SIRS criteria (>10% bands meets the WBC criterion). Unfortunately, this is not a very specific indicator – many inflammatory and infectious states cause increased bands (or a left shift) besides sepsis.
It turns out that other more subtle leukocyte changes may be better markers for sepsis. One such marker is the monocyte distribution width (MDW), which is analogous to the red blood cell distribution width (RDW) used to diagnose red blood cell disorders like anemias. Monocytes and macrophages are the frontline first responders of the immune system and undergo subtle but detectable changes in size and morphology during infection, especially serious infection like sepsis.
Modern analyzers have advanced to the point where they can not only count all types of blood cells, but also accurately characterize subtle differences in their size, shape and composition. Beckman Coulter analyzers, for example, use a technique called VCS, which stands for Volume, Conductivity and Scatter, to analyze blood cells with great accuracy and efficiency. This method uses electrical (impedance) and optical measurements (light scatter) using multiple lasers, as well as sophisticated statistical algorithms, to quickly detect very subtle changes in cell properties. If you’re interested in learning more about VCS, and in general about how modern blood analyzers do their magic, you can read more about it here.
The new test from Beckman Coulter, ESI, is essentially MDW measured using VCS in the company’s latest hematology analyzers. The test has been approved in Europe and will be rolled out in the coming months on the DxH 900 analyzer. ESI is also being evaluated by the FDA in the US, and the company expects a 510k approval later in 2018, followed by a roll-out of ESI in the US market. To learn more about ESI and the science behind MDW changes in sepsis, have a look at the Laboratory Tests section of our Sepsis app.
We believe ESI is a valuable new addition to the armamentarium of sepsis tests that promises to reduce the time to diagnosis and treatment. ESCAVO is proud to partner in our sepsis education efforts with Beckman Coulter, a company committed to bringing new tools to the fight against sepsis.
Daniel Nichita, MD
And the ESCAVO Team