Can a Newer Test Remove the Mystery of Diagnosing Sepsis?

When patients present to the emergency department (ED), providers can often have challenges diagnosing patients who may be in a health crisis and have sepsis. As time is of the essence, there are clues patients may have sepsis but there has been no definitive test to diagnose the condition.

In addition, ED providers have to strike a balance between early intervention for sepsis against the potential use of intensive care utilizing expensive resources, especially in the absence of no positive test.

“I think there is a lot of confusion in the current standard of care in how we diagnose sepsis,” said Hollis O’Neal, MD, MSc associate professor of Medicine at LSU Health Sciences Center and medical director of research Our Lady of the Lake Regional Medical Center, Baton Rouge, LA. “There is good reason for that confusion because there is no standardized process for it. There are some criteria that we use that alert us that a patient may or may not have an infection. These are known as the surge criteria.”

O’Neal and colleagues saw this problem and wanted to see if a new rapid diagnostic could aid ED physicians in getting to a sepsis diagnosis sooner.

O’Neal is presenting this research at the ongoing European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) conference with his poster, "Assessment of a rapid cellular host response test in predicting sepsis in a normal lactate subpopulation of ED patients suspected of infection."

What they found was a way to differentiate patients in a septic state. They utilized the IntelliSep test (ISI) that was performed on the Cytovale system benchtop instrument, which is a semi-quantitative invitro test that assesses cellular host response via deformability cytometry of leukocyte biophysical properties from a routine whole blood specimen, according to the investigators. These properties have been shown to differ in the septic patient when compared to those in the quiescent state.

“The ISI, a quantitative measure of innate host immune activation, may have the potential to aid ED clinicians in rapid risk stratification of sepsis for patients presenting with signs or suspicion of infection without elevated lactate levels,” O’Neal and his colleagues wrote.

The investigators looked at 424 patients who were stratified by the test, including 185 patients in what they identified as Band 1, 123 patients in Band 2, and 116 in Band 3.

In terms of the results, this is what they reported:

•Upon retrospective adjudication, 24.3% of patients with normal lactate levels were adjudicated as septic.

•48.3% of Band 3 patients were found to be septic compared to 24.4% of those in the Band 2 and 9.2% of those in Band 1.

•Band 3 patients were 2 and 5 times more likely to have positive blood cultures than those in Band 2 and Band 1, respectively (p<10-4 and p<10-9).

•Among survivors, Band 3 patients on average had 2.2 and 2.4 days longer hospital stays than those in Band 2 and Band 1(p<0.01).

Some of the benefits of the test according to O’Neal are the small amount of blood needed that is typically extracted from patients presenting to the ER, and the quickness of the test's results. A completed test can be analyzed in under 10 minutes according to the test's manufacturer.

The test had good predictive value of sepsis, according to O’Neal and may aid ED personnel treating these patients.

“The goal is to help the ED providers get to a diagnosis of sepsis or rule it out more quickly,” O’Neal said.

Contagion spoke to O’Neal about the ongoing challenges in diagnosing sepsis, as well as his research utilizing the ISI test.