What laboratory tests are indicated for a patient presenting with vertigo?

From the Guidelines

For patients with vertigo, I recommend ordering a comprehensive set of laboratory tests, including a complete blood count (CBC), comprehensive metabolic panel, thyroid function tests (TSH, free T4), hemoglobin A1c, vitamin B12, and folate levels, as well as considering erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) if an autoimmune cause is suspected, to help determine the underlying cause of vertigo, as suggested by the clinical practice guideline for Ménière's disease 1. When evaluating a patient with vertigo, it is essential to consider the potential causes, including vestibular disorders such as benign paroxysmal positional vertigo (BPPV) or Ménière's disease, as well as other conditions like thyroid disorders, diabetes, or autoimmune diseases. The laboratory tests should be guided by the patient's history, physical examination findings, and associated symptoms to maximize diagnostic yield. Some key points to consider when ordering laboratory tests for vertigo include:

• A complete blood count (CBC) to assess for anemia or infection
• Comprehensive metabolic panel to evaluate kidney and liver function
• Thyroid function tests (TSH, free T4) to rule out thyroid disorders
• Hemoglobin A1c to screen for diabetes, which can cause vestibular dysfunction
• Vitamin B12 and folate levels to check for deficiencies that can contribute to neurological symptoms, including vertigo
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to help identify inflammation if an autoimmune cause is suspected It's also important to note that many vestibular disorders like BPPV or Ménière's disease may not show abnormalities on standard blood tests, as stated in the clinical practice guideline for BPPV 1. Therefore, the laboratory evaluation should be individualized and based on the patient's specific presentation and risk factors. In cases where vascular causes are considered, lipid panel and homocysteine levels may be useful, and for patients with recurrent unexplained vertigo, consider testing for Lyme disease in endemic areas. The clinical practice guideline for Ménière's disease 1 provides a comprehensive approach to evaluating and managing patients with vertigo, including the use of laboratory tests and other diagnostic tools.

From the Research

Laboratory Tests for Vertigo

To determine the cause of vertigo, several laboratory tests can be ordered, including:

• Complete blood count (CBC) to rule out anemia or infection 2
• Electrolyte panel to check for electrolyte imbalances 2
• Thyroid function tests to evaluate thyroid hormone levels 2
• Vitamin B12 level to assess for deficiency 2
• Erythrocyte sedimentation rate (ESR) and high sensitivity C-reactive protein (hsCRP) to evaluate inflammation 2
• Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte to HDL-cholesterol ratio (MHR) to assess inflammatory biomarkers 2

Imaging Studies for Vertigo

Imaging studies such as magnetic resonance imaging (MRI) may be ordered to rule out central causes of vertigo, such as:

• Cerebrovascular disease 3
• Multiple sclerosis 3
• Intracranial neoplasms 3
• Meniere's disease with visualization of an endolymphatic hydrops using intratympanic gadolinium application 4

Special Tests for Vertigo

Special tests such as:

• Dix-Hallpike maneuver to diagnose benign paroxysmal positional vertigo (BPPV) 3, 5, 6
• Video head impulse test and vestibular evoked myogenic potentials to assess vestibular function 4
• HINTS (head-impulse, nystagmus, test of skew) examination to distinguish peripheral from central etiologies 5