How Fibromyalgia Is Diagnosed

Diagnosis begins by excluding other causes

Fibromyalgia is a difficult disorder to diagnose. Because it is so poorly understood, there is no clear consensus as to what measures could or should be used to confirm it. Moreover, even if you have signs of the disorder—including chronic widespread pain and fatigue—available lab and imaging tests will often appear perfectly normal. 

The only way to get a fibromyalgia diagnosis is to embark on a "diagnosis of exclusion."

This can be a painstaking process in which your healthcare provider reviews and weeds out many other possible causes of your symptoms. Only when these causes are excluded can a diagnosis of fibromyalgia be made.

fibromyalgia diagnosis
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Diagnostic Criteria

Because there is no test available to confirm fibromyalgia, your healthcare provider must rely solely on your panel of symptoms to make a diagnosis. The diagnosis is typically overseen by a medical specialist known as a rheumatologist who specializes in musculoskeletal diseases and autoimmune disorders. Some neurologists and general practitioners may also have the experience to oversee the evaluation.

The criteria for diagnosis was established by the American College of Rheumatology (ACR) in 1990 and then updated in 2010 to allow for a more practical approach to diagnosis. Instead of diagnosing the disorder based on the history and location of the pain, the current guidelines instruct healthcare providers to evaluate three key criteria:

  1. How widespread the pain is and how you experience symptoms
  2. Whether the symptoms have persisted at this level for at least three months
  3. Whether there are no other explanations for the symptoms

The score-based ACR Fibromyalgia Diagnostic Criteria system includes an evaluation called the widespread pain index (WPI) and another called the symptom severity (SS) scale.

While the ACR system is commonly used, it does have its detractors who believe that fibromyalgia should not be evaluated as a purely somatic (physical) disorder but one in which psychological factors and psychosocial stresses are also assessed.

Exclusionary Diagnosis

Before closely evaluating your current symptoms, your healthcare provider needs to exclude other diseases or disorders with similar symptoms and characteristics. Depending on the range of symptoms you have (digestive, urinary, psychological, etc.), the list can become quite extensive.

Among the possibilities:

The challenge in diagnosing fibromyalgia is that other conditions can often co-exist with fibromyalgia and have similar or overlapping symptoms. For instance, if arthritis or sleep apnea is diagnosed, the diagnosis might explain some of the key symptoms you are experiencing, but not others.

That's why it can really help to have a healthcare provider experienced with fibromyalgia, so they can make the subtle distinctions.

Fibromyalgia Doctor Discussion Guide

Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.

Doctor Discussion Guide Old Woman

Widespread Pain Index

The widespread pain index (WPI) breaks the body down into 19 sections, each of which is considered a characteristic area of involvement. Your healthcare provider will ask if you experienced pain in each area in the past week. A score of 1 is registered for every "yes" you give.

You may also be asked to characterize the type of pain you have (such as severe or diffuse) or consider tender points (pain trigger points) that used to be central to the diagnosis.

The 19 pain sites included in the evaluation are (from top to bottom):

  • Right jaw
  • Left jaw
  • Neck
  • Right shoulder girdle
  • Left shoulder girdle
  • Right upper arm
  • Left upper arm
  • Right lower arm
  • Left lower arm
  • Upper back
  • Lower back
  • Chest
  • Abdomen
  • Right hip/buttock/upper thigh
  • Left hip/buttock/upper thigh
  • Right upper leg
  • Left upper leg
  • Right lower leg
  • Left lower leg

The maximum score for the WPI is 19.

Symptom Severity Scale

The symptom severity (SS) scale evaluates four symptoms considered defining in a fibromyalgia diagnosis. Each symptom is scored on a scale of 0 to 3, with 0 meaning no symptoms; 1 meaning mild symptoms; 2 meaning moderate symptoms; and 3 meaning serious symptoms. The score is based purely on the severity of symptoms that have occurred within the past week.

The four symptoms evaluated in the criteria are:

The maximum score on the SS scale is 12.

Confirming the Diagnosis

If no other explanation for your symptoms can be found, your healthcare provider will look to see if your combined WPI and SS scores meet either one of two ACR criteria for possible fibromyalgia diagnosis:

  • A WPI score of 7 or more AND an SS score of 5 or more
  • A WPI score of 3 to 6 AND an SS score of 9 or more

Thereafter, if the healthcare provider can establish that your symptoms have been present at the same or similar level for at least three months, you would be officially diagnosed as having fibromyalgia.

Once the diagnosis is confirmed, you and your healthcare provider can then begin exploring treatment options. This can be another long and protracted process, but one that can put you on the road to better health and sustained remission.

Frequently Asked Questions

  • How does a healthcare provider diagnose fibromyalgia?

    Fibromyalgia is diagnosed based on the widespread pain index (WPI) and the symptom severity scale (SS). WPI identifies pain locations while SS evaluates other symptoms including fatigue, sleep quality, cognitive difficulties, and somatic symptoms including dizziness, fainting, nausea, and bowel disorders.

  • What are the “18 tender points” of fibromyalgia?

    The old diagnostic criteria for fibromyalgia were based on having at least 11 of 18 specific tender points found in the front of the neck, below the collarbone, back of the neck, back of shoulders, shoulder blades, outsides of the elbows, upper-outer buttocks, outsides of the hips, and inner knees.

  • What medical tests check for fibromyalgia?

    Unfortunately, there are no blood tests that confirm a fibromyalgia diagnosis. Imaging studies also typically appear normal in fibromyalgia. Fibromyalgia is diagnosed based on symptoms and history, and after other conditions have been ruled out.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Fibromyalgia.

  2. Wolfe F, Walitt B, Katz R, Häuser W. Symptoms, the Nature of Fibromyalgia, and Diagnostic and Statistical Manual 5 (DSM-5) Defined Mental Illness in Patients with Rheumatoid Arthritis and Fibromyalgia. PLoS ONE. 2014;9(2):e88740. doi:10.1371/journal.pone.0088740

  3. Fitzcharles MA, Perrot S, Häuser W. Comorbid fibromyalgia: A qualitative review of prevalence and importance. Eur J Pain. 2018;22(9):1565-1576. doi:10.1002/ejp.1252


Additional Reading

By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.