(HealthDay)—A new scale for rating the severity of mononucleosis can identify patients at risk for more serious cases, including those who might develop chronic fatigue syndrome following infectious mononucleosis, according to a study recently published in The Journal of Pediatrics.

Ben Z. Katz, M.D., from the Northwestern University Feinberg School of Medicine in Chicago, and colleagues developed and validated a scale for measuring severity of mononucleosis among 126 with .

The researchers found that concordance between the two physician reviewers for use of the mononucleosis scale was 95 percent. Severity of mononucleosis scores were ≥2 among all three hospitalized patients. Patients with severity of mononucleosis scores ≥1 were 1.83 times as likely to be given corticosteroids. Six months following infectious mononucleosis, infected students with severity of mononucleosis scores of 0 or 1 were less likely to meet more than one case definition of .

"The severity of mononucleosis scale has interobserver, concurrent, and predictive validity for hospitalization, corticosteroid use, and meeting criteria for chronic fatigue syndrome six months following infectious mononucleosis," the authors write.