How Fibromyalgia Is Diagnosed – A Comprehensive Guide

Fibromyalgia (FM) is a clinical diagnosis of chronic widespread pain with central sensitization. No single confirmatory test exists.

2016 ACR Diagnostic Criteria (Modified)

• Widespread Pain Index (WPI) ≥7 AND Symptom Severity Scale (SSS) ≥5 OR WPI 4–6 AND SSS ≥9.
• Symptoms present ≥3 months.
• No other disorder fully explains the pain.

WPI: 19 body areas. SSS: fatigue, unrefreshing sleep, cognitive symptoms (0–3 each) + somatic symptoms count (0–3).

Typical Symptom Cluster

• Chronic widespread pain (axial + quadrants).
• Profound fatigue.
• Non-restorative sleep.
• "Fibro fog" (cognitive dysfunction).
• Headaches (tension, migraine).
• IBS/functional GI.
• Depression/anxiety (comorbid, not diagnostic).

Exclusionary Workup (Rule Out Mimics)

• CBC, CMP, TSH, free T4.
• ESR, CRP (usually normal in FM).
• RF, ANA, CCP (if joint symptoms).
• CK (if myopathy suspected).
• Vitamin D, B12, iron studies.
• Lyme serology (if endemic).
• Sleep study (if apnea symptoms).

Multimodal Treatment

• Pharmacologic: Duloxetine, milnacipran, pregabalin, low-dose amitriptyline/cyclobenzaprine (sleep). Opioids discouraged.
• Non-pharmacologic (core): Graded aerobic exercise, CBT, mindfulness, sleep hygiene, tai chi/yoga.
• Education: Pain neuroscience, pacing, self-efficacy.

Key Message

Diagnosis is positive (meeting criteria), not just exclusionary. Validating the diagnosis enables effective, evidence-based management.