What initial laboratory tests should be ordered for a patient presenting with vertigo?

Laboratory Testing for Vertigo

Routine laboratory tests are generally not indicated for patients presenting with vertigo, as the diagnosis relies primarily on clinical history, timing of symptoms, and physical examination maneuvers rather than blood work. 1

Why Labs Are Not Routinely Recommended

The American Academy of Otolaryngology-Head and Neck Surgery guidelines explicitly list blood tests (complete blood count, serum chemistry) among diagnostic interventions considered but do not recommend them as standard practice for benign paroxysmal positional vertigo (BPPV), which accounts for 85-95% of vertigo cases. 1 The diagnosis of vertigo is fundamentally clinical, based on symptom timing, triggers, and targeted physical examination rather than laboratory values. 2

When to Consider Laboratory Testing

Laboratory tests should be reserved for specific clinical scenarios where the history suggests systemic or infectious causes:

Suspected Ménière's Disease

• No specific labs are required for diagnosis, which is made clinically based on episodic vertigo lasting 20 minutes to 12 hours with fluctuating hearing loss, tinnitus, or ear fullness. 1
• Labs are only useful to exclude other conditions when the presentation is atypical. 1

Red Flag Presentations Requiring Workup

• Suspected autoimmune causes: Consider autoimmune panels when there is progressive fluctuating bilateral hearing loss that may be steroid-responsive, especially with concurrent vision, skin, or joint problems. 1
• Suspected infectious causes (Lyme disease, otosyphilis): Order appropriate serologic testing when vertigo presents with severe otalgia, fever, or sudden bilateral hearing loss. 1
• Suspected stroke/central causes: Laboratory testing is not the priority—urgent MRI brain without and with IV contrast is indicated instead when there are central warning signs, positive Romberg test, severe postural instability, or focal neurologic deficits. 2

The Diagnostic Priority: Clinical Assessment Over Labs

The most effective diagnostic approach focuses on:

• Timing and triggers of vertigo episodes (triggered vs. spontaneous, seconds vs. minutes vs. days) rather than laboratory values. 2, 3
• Physical examination maneuvers: Dix-Hallpike for posterior canal BPPV, Supine Roll Test for lateral canal BPPV, and HINTS examination (Head Impulse, Nystagmus, Test of Skew) to differentiate peripheral from central causes with 92.9% sensitivity. 2, 4
• Audiometry when there are auditory symptoms suggesting Ménière's disease or other inner ear pathology. 1

Common Pitfalls to Avoid

• Ordering routine labs reflexively without specific clinical indications wastes resources and delays appropriate diagnosis, which depends on clinical examination. 1
• Assuming labs will exclude stroke: Up to 75-80% of posterior circulation strokes causing vertigo lack focal neurologic deficits initially, and diagnosis requires MRI with diffusion-weighted imaging, not laboratory testing. 2
• Failing to perform appropriate physical examination maneuvers (Dix-Hallpike, HINTS) in favor of ordering labs, which misses the opportunity for immediate bedside diagnosis of BPPV or identification of central causes. 2, 4