Laboratory Tests for Evaluating Migraine Causes
Laboratory testing is generally not recommended for diagnosing the cause of migraines, as migraine is primarily a clinical diagnosis based on history and symptoms rather than laboratory findings. 1
Diagnostic Approach for Migraine
- Migraine diagnosis should be based on clinical features using validated criteria from the International Headache Society, not laboratory tests 1
- Validated screening tools like the three-item ID-Migraine questionnaire (sensitivity 0.81, specificity 0.75) or the five-item Migraine Screen Questionnaire (sensitivity 0.93, specificity 0.81) can help identify likely migraine cases 1
- Headache diaries documenting pattern, frequency, accompanying symptoms (nausea, photophobia, phonophobia), and medication use are more valuable than laboratory tests for diagnosis 1
When Laboratory Testing Is Indicated
Laboratory testing should only be performed when "red flags" suggest a secondary headache disorder:
- Thunderclap headache (sudden onset reaching maximum intensity within seconds to minutes) 2
- Atypical aura (may indicate TIA, stroke, or other neurological conditions) 2
- Progressive headache worsening over time 2
- Headache onset after age 50 2
- Headache described as "worst headache of life" 2
- Unexplained fever or neck stiffness (possible meningitis) 2
- Focal neurological symptoms 2
- Weight loss or altered consciousness 2
Recommended Tests When Red Flags Are Present
When red flags are present, the following may be indicated:
- Neuroimaging (MRI preferred over CT except when acute intracranial hemorrhage is suspected) 1, 2
- Complete blood count with differential (to evaluate for infection or systemic illness) 3
- Basic metabolic panel (to assess for electrolyte abnormalities) 3
- Erythrocyte sedimentation rate and C-reactive protein (especially in older patients to evaluate for temporal arteritis) 2, 3
- Cerebrospinal fluid examination (when infection or subarachnoid hemorrhage is suspected) 3
Research on Laboratory Tests in Migraine
Some research has explored potential associations between laboratory values and migraine, but these remain investigational:
- Some studies have found altered inflammatory markers in migraine patients, including neutrophil/monocyte ratio (NMR) and platelet/lymphocyte ratio (PLR), but these are not established diagnostic tests 4
- Research has suggested potential associations between migraine and biomarkers of cardiovascular disease risk, iron deficiency, and liver function, but these relationships appear to reflect biological pleiotropy rather than causality 5
- Historical research has explored platelet function in migraine, but this has not translated to routine clinical testing 6
Common Pitfalls to Avoid
- Ordering unnecessary laboratory tests for typical migraine presentations without red flags 1
- Failing to recognize red flag symptoms that warrant further investigation 2
- Relying on laboratory tests rather than clinical criteria for primary migraine diagnosis 1
- Overlooking the need for neuroimaging when red flags are present 2
Conclusion
For typical migraine presentations without red flags, laboratory testing is not indicated as it does not contribute to diagnosis or management. The diagnosis of migraine remains primarily clinical, based on history, symptoms, and validated diagnostic criteria.