From the Guidelines
Fibromyalgia diagnosis cannot be confirmed with a specific blood test, and instead, bloodwork is used to rule out other conditions with similar symptoms. The diagnosis of fibromyalgia is primarily clinical, based on symptoms such as widespread pain lasting at least three months, fatigue, sleep disturbances, and cognitive difficulties, along with physical examination findings of multiple tender points 1. Common blood tests used to exclude other conditions include:
- Complete blood count (CBC)
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
- Thyroid function tests
- Rheumatoid factor
- Antinuclear antibody tests These tests help exclude conditions like rheumatoid arthritis, lupus, thyroid disorders, and other inflammatory or autoimmune diseases. Additionally, vitamin D levels and comprehensive metabolic panels may be checked as deficiencies can contribute to pain symptoms. It's essential to note that if bloodwork returns normal results while symptoms persist, this actually supports a fibromyalgia diagnosis, as it's characterized by pain without observable inflammation or tissue damage. Newer tests like the FM/a blood test claim to identify fibromyalgia markers, but these aren't widely accepted in clinical practice, and the European League Against Rheumatism (EULAR) revised recommendations for the management of fibromyalgia do not include specific blood tests for diagnosis 1.
From the Research
Bloodwork for Diagnosing Fibromyalgia
The diagnosis of fibromyalgia is primarily based on exclusion, and bloodwork plays a crucial role in ruling out other causes of joint or muscle pain. The following blood tests are recommended:
- Complete blood count (CBC) 2
- Erythrocyte sedimentation rate (ESR) 2, 3
- Liver function tests 2
- Hepatitis C antibody 2
- Calcium 2
- Thyrotropin 2
- C-reactive protein (CRP) 3
- Neutrophil lymphocyte ratio (NLR) 3
- Mean platelet volume (MPV) 3, 4
- Platelet distribution width (PDW) 3
Inflammatory Markers
Research suggests that inflammatory markers, such as ESR, CRP, NLR, and MPV, may be useful in diagnosing fibromyalgia and assessing disease severity 3. These markers are often elevated in patients with fibromyalgia, indicating a possible inflammatory basis for the disease.
Cardiovascular Risk Factors
Studies have also shown that patients with fibromyalgia may have an increased risk of cardiovascular disease, and mean platelet volume (MPV) may be a useful marker for assessing this risk 4. Elevated MPV levels have been found in patients with fibromyalgia, suggesting increased platelet activation and a higher risk of future cardiovascular disease.