More Accurate Test Gives Indication of Early Meningococcal Infection

According to the researchers, the method for diagnosis could save lives by getting patients treatment earlier, when the infection is most treatable.

Michael Cooperstock, MD, professor of child health in the Division of Pediatric Infectious Diseases at the MU School of Medicine, medical director of infection control at University of Missouri Health Care and senior author of the study said, "When we talk about early diagnosis, we're not talking about days, but rather hours and even minutes."

"Diagnosis of most bacterial infections traditionally has relied upon the detection of an increase in the total number of white blood cells," said Prof. Cooperstock. "That's because an increase in a patient's white blood cell count is an indication of acute inflammation associated with infection."

When the investigators studied 216 cases from the US Multicenter Meningococcal Surveillance Study, they found that 33% of the patients with active infections had total white blood cell counts that appeared normal. After examining the patients' blood tests more closely, the researchers found that a better indicator of infection was not the total white blood cell count but rather abnormalities in two particular types of white blood cells called neutrophils.

"When we looked at the neutrophil counts of each patient, we examined not only the total number of neutrophils, but also the number of immature neutrophils and the ratio of immature to total neutrophil cells," Prof. Cooperstock said. "We found that 94% of the patients showed an abnormality of one or more of these three tests, indicating a serious infection might be present. Reliance on the total white blood cell count alone, however, would have given false reassurance that infection was not present in more than 30% of those cases."

The researchers concluded that if any of the three neutrophil indicators are outside a certain range, there is a possibility that the patient has a serious bacterial infection, including the possibility of meningococcal disease, and would need careful attention.

The study was published in the October 2013 edition of the Pediatric Infectious Disease Journal.

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