The required symptoms, listed below, must be persistently or recurrently present for at least 6 months in adults (3 months in children and adolescents). If other conditions have the same symptoms, those conditions must be assessed and treated optimally first before a diagnosis of ME/CFS can be made. Exclusionary conditions should be ruled out by a combination of clinical history, physical examination, and complementary tests. Pathological fatigue Post-exertional malaise and worsening of symptoms Sleep dysfunction Pain Cognitive symptoms (at least two symptoms from a list provided) In addition, at least one symptom from two from the following categories of symptoms are required: Autonomic Neuroendocrine Immune