The first U.S. Case Definition for the Chronic Fatigue Syndrome (CFS) was published by researchers under the auspices of the Centers for Disease Control & Prevention (CDC) in 1988 in the prestigious journal Annals of Internal Medicine. The case definition is as follows:
"A case of the chronic fatigue syndrome must fulfill major criteria 1 and 2, and the following minor criteria: (a) 6 (or more) of the 11 symptom criteria and 2 (or more) of the 3 physical criteria; or (b) 8 (or more) of the symptom criteria."
"...chronic psychiatric disease, either newly diagnosed or by history (such as endogenous depression; hysterical personality disorder; anxiety neurosis, schizophrenia..."
[Comment: These psychiatric diagnoses as a basis for exclusion of a CFS diagnosis were substantially removed from the 1994 CDC definition, especially those not related to major mental illness. The 1994 Definition recognized that anxiety and secondary depression were likely to occur as a result of chronic physical illness. This is one of the few elements of the 1988 definition that was improved in the 1994 definition.]
"...or chronic use of major tranquilizers, lithium, or antidepressive medication); chronic inflammatory disease (such as sarcoidosis, Wegener granulomatosis, or chronic hepatitis); neuromuscular disease (such as multiple sclerosis or myasthenia gravis); endocrine disease (such as hypothyroidism, Addison's disease, Cushing Syndrome, or diabetes mellitus); drug dependency or abuse (such as alcohol; controlled prescription drugs, or illicit drugs); side effects of a chronic medication or other toxic agent (such as a chemical solvent, pesticide, or heavy metal); or other known or defined chronic pulmonary, cardiac, gastrointestinal, hepatic, renal, or hematologic disease."
"Specific lab tests or clinical measurements are not required to satisfy the definition of chronic fatigue syndrome, but the recommended evaluation includes serial weight measurements...serial morning and afternoon temperature measurements; complete blood count and differential; serum electrolytes; glucose; creatinine; blood urea nitrogen; calcium, phosphorous; total bilirubin; alkaline phosphatase; serum aspartate aminotransferase, serum alanine aminotransferase; creatine phosphokinase or aldolase; urinanalysis...personal and family psychiatric history ...erythrocyte sedimentation rate; antinuclear antibody; thyroid stimulating hormone level; HIV antibody measurement;...and PPD skin test with controls."
"If any of the above are abnormal, the physician should search for other conditions that may cause such a result. If no such conditions are detected by a reasonable evaluation, this criterion is satisfied."
Symptom Criteria
"To fulfill a symptom criterion, a symptom must have begun at or after the time of onset of increased fatigability, and must have persisted or recurred over a period of at least six months. (Individual symptoms may or may not have occurred simultaneously.) Symptoms include:
Mild fever—oral temperature between 37.5 C and 38.6 C if measured by the patient—or chills. (Note: oral temperatures of greater than 38.6 C. are less compatible with chronic fatigue syndrome and should prompt studies for other causes of illness.)
Physical Criteria
"Physical criteria must be documented by a physician on at least two occasions, at least one month apart.