What bloodwork is recommended to check for migraines or headaches?

Bloodwork for Migraines and Headaches

Routine bloodwork is not recommended for the diagnosis of primary headaches like migraine or tension-type headache, as the diagnosis is made clinically based on history and physical examination. 1

When Blood Tests Are NOT Indicated

• Primary headaches (migraine, tension-type) with normal neurological examination do not require blood testing for diagnosis. 1
• The medical history is the mainstay of migraine diagnosis, requiring documentation of age at onset, duration, frequency, pain characteristics, accompanying symptoms (photophobia, phonophobia, nausea/vomiting), and aura symptoms. 1
• Physical examination is most often confirmatory, and further investigations including blood samples are only occasionally required to confirm or reject suspicions of secondary causes. 1

When Blood Tests ARE Indicated

Blood testing becomes appropriate when you suspect a secondary headache disorder rather than primary migraine or tension-type headache. Consider the following scenarios:

Red Flag Situations Requiring Laboratory Evaluation

• New-onset headache in patients over age 50 years warrants evaluation for temporal arteritis with erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), as 10-36% of temporal arteritis patients may have normal ESR. 2
• Progressively worsening headache pattern suggests possible secondary causes requiring metabolic workup. 3
• Headache with abnormal neurological examination necessitates investigation for underlying systemic or metabolic disorders. 1, 3

Specific Blood Tests for Secondary Headache Evaluation

When secondary causes are suspected, the following laboratory tests should be ordered:

• Thyroid function tests (TSH, free T4) to evaluate for hypothyroidism or hyperthyroidism, both of which can cause headaches. 4
• Complete blood count (CBC) to assess for anemia or hematologic abnormalities that could contribute to symptoms. 4
• Basic metabolic panel to evaluate electrolyte disturbances, kidney function, and glucose levels. 4
• Liver function tests to rule out hepatic causes. 4
• Serum calcium to evaluate for hyperparathyroidism, which can rarely present with headache. 4

Diagnostic Approach Algorithm

Step 1: Clinical Diagnosis

Apply International Classification of Headache Disorders (ICHD-3) criteria based on history alone—this establishes the diagnosis in most primary headache cases. 1

Step 2: Identify Red Flags

Screen for features suggesting secondary causes:

• Headache worsened by Valsalva maneuver 3
• Headache awakening patient from sleep 3
• New headache in older adults (>50 years) 2
• Abnormal neurological findings 1, 3

Step 3: Order Appropriate Testing

• If no red flags present: No blood testing or neuroimaging needed. 1
• If red flags present: Order targeted blood tests based on suspected secondary cause, plus neuroimaging (MRI preferred over CT). 1, 3

Common Pitfalls to Avoid

• Do not order "routine headache panels"—there is no such thing. Blood testing should be targeted based on specific clinical suspicion of secondary causes. 1
• Avoid confusing diagnostic testing with screening—the yield of neuroimaging and blood testing in patients with primary headache and normal examination is extremely low (0.2% for migraine, 0% for tension-type headache). 1
• Do not mistake "sinus headache" for a separate entity—approximately 62% of pediatric migraineurs have cranial autonomic symptoms like rhinorrhea, and many adult migraineurs are misdiagnosed with sinus headache. 1

Additional Diagnostic Tools (Not Blood Tests)

Instead of bloodwork, utilize these validated clinical tools for migraine diagnosis:

• Headache diary documenting frequency, duration, intensity, and associated symptoms. 1, 3
• ID-Migraine questionnaire (3 questions: nausea, photophobia, disability) with 81% sensitivity and 93% positive predictive value. 1
• Migraine Screen Questionnaire (MS-Q) with 93% sensitivity and 81% specificity. 1