A Chronic Fatigue Syndrome (CFS) severity score based on case designation criteria

James N. Baraniuk, Oluwatoyin Adewuyi, Samantha Jean Merck, Mushtaq Ali, Murugan K. Ravindran, Christian R. Timbol, Rakib Rayhan, Yin Zheng, Uyenphuong Le, Rania Esteitie, Kristina N. Petrie

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Background: Chronic Fatigue Syndrome case designation criteria are scored as physicians' subjective, nominal interpretations of patient fatigue, pain (headaches, myalgia, arthralgia, sore throat and lymph nodes), cognitive dysfunction, sleep and exertional exhaustion. Methods: Subjects self-reported symptoms using an anchored ordinal scale of 0 (no symptom), 1 (trivial complaints), 2 (mild), 3 (moderate), and 4 (severe). Fatigue of 3 or 4 distinguished "Fatigued" from "Not Fatigued" subjects. The sum of the 8(Sum8) ancillary criteria was tested as a proxy for fatigue. All subjects had history and physical examinations to exclude medical fatigue, and ensure categorization as healthy or CFS subjects. Results: Fatigued subjects were divided into CFS with ≥4 symptoms or Chronic Idiopathic Fatigue (CIF) with ≤3 symptoms. ROC of Sum8 for CFS and Not Fatigued subjects generated a threshold of 14 (specificity=0.934; sensitivity=0.928). CFS (n=256) and CIF (n=55) criteria were refined to include Sum8≥14 and ≤13, respectively. Not Fatigued subjects had highly skewed Sum8 responses. Healthy Controls (HC; n=269) were defined by fatigue≤2 and Sum8≤13. Those with Sum8≥14 were defned as CFS-Like With Insufficient Fatigue Syndrome (CFSLWIFS; n=20). Sum8 and Fatigue were highly correlated (R2=0.977; Cronbach's alpha=0.924) indicating an intimate relationship between symptom constructs. Cluster analysis suggested 4 clades each in CFS and HC. Trans-lational utility was inferred from the clustering of proteomics from cerebrospinal fluid. Conclusions: Plotting Fatigue severity versus Sum8 produced an internally consistent classifying system. This is a necessary step for translating symptom profiles into fatigue phenotypes and their pathophysiological mechanisms.

Original languageEnglish (US)
Pages (from-to)53-68
Number of pages16
JournalAmerican Journal of Translational Research
Issue number1
StatePublished - 2013
Externally publishedYes


  • Fatigue
  • Fbromyalgia
  • Myalgic encephalomyelitis
  • Pain
  • Proteomics

ASJC Scopus subject areas

  • Molecular Medicine
  • Clinical Biochemistry
  • Cancer Research


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