Diagnosis:

There is no obvious, objective method for diagnosing fibromyalgia. The criteria used for studying fibromyalgia are very helpful, particularly if the patient does not have an accompanying disorder, such as depression or arthritis, that could complicate the diagnosis. Failure to meet the criteria, however, does not rule out fibromyalgia. Fibromyalgia should be suspected in any person who has muscle and joint pain with no identifiable cause.

Criteria for Classifying Fibromyalgia

In 1990, the American College of Rheumatology (ACR) set the following criteria for classifying fibromyalgia:

A. Widespread pain must be present for at least 3 months. This pain must appear in all of the following locations:

• Both sides of the body
• Above and below the waist
• Along the length of the spine

B. Pain in at least 11 of 18 specific areas called tender points on the body. The pain experienced when pressing on a tender point is very localized and intensely painful (not just tender). Tender points are located in the following areas:

• The left or right side of the back of the neck, directly below the hairline
• The left or right side of the front of the neck, above the collarbone (clavicle)
• The left or right side of the chest, right below the collarbone
• The left or right side of the upper back, near where the neck and shoulder join
• The left or right side of the spine in the upper back between the shoulder blades (scapula)
• The inside of either arm where it bends at the elbow
• The left or right side of the lower back, right below the waist
• Either side of the buttocks below the hip bones
• Either kneecap

Other Factors. The ACR classification provides a guideline, but doctors will also use a patient's medical history and other symptoms to reach a diagnosis. Fibromyalgia is often diagnosed when other diseases have been excluded. Long-term symptoms that may indicate fibromyalgia include:

• Fatigue
• Headache
• Morning stiffness
• Numbness or tingling in the hands and feet
• Sleep disturbance

The 18 fibromyalgia tender points are located throughout the body. According to the American College of Rheumatology, a diagnosis of fibromyalgia requires widespread body pain plus localized pain in 11 of these 18 specific points.

Medical and Personal History

A doctor should always take a careful personal and family medical history, which includes a psychological profile and history of any factors that might indicate other conditions, such as:

• Infectious diseases
• Muscle weakness
• Physical injuries
• Rashes
• Recent weight change
• Sexual, physical, or substance or alcohol abuse

Patients should report any drugs they take, including vitamins and over-the-counter or herbal medications.

Physical Examination

Pressure on Tender Spots. Any physical examination for fibromyalgia requires that the doctor press firmly on all potential tender spots. These spots must be painful when pressed, not simply tender. In addition, for a doctor to reach a diagnosis of fibromyalgia, these tender sites should normally not show signs of inflammation (redness, swelling, or heat in the joints and soft tissue). The tender points may also change in location and sensitivity over time. A doctor may then recheck tender points that do not respond the first time in patients who have other significant symptoms.

Detection of Other Causes of Symptoms. A health care provider will also examine the nails, skin, mucus membranes, joints, spine, muscles, and bones to help rule out arthritis, thyroid disease, and other disorders.

Other Tests

No blood, urine, or other laboratory tests can definitively diagnose fibromyalgia. If such tests show abnormal results, the doctor should look for other disorders. Tests for specific diseases depend on family histories and other symptoms, and may include:

• Blood count
• Sedimentation rate
• Tests of certain antibodies
• Thyroid and liver function tests

The doctor may suggest follow-up psychological profile testing, if laboratory results do not indicate a specific disease.