Tinnitus — Blood Tests and What to Check
Ringing, buzzing, or whooshing in your ears can have blood-testable causes including iron deficiency, B12, thyroid dysfunction, and vascular risk factors — many of which are treatable.
The Quick Answer
Tinnitus — ringing, buzzing, hissing, or whooshing in the ears — affects roughly 15% of Australian adults. While noise exposure and age-related hearing loss are the most common causes, a significant proportion of tinnitus cases have a blood-testable, treatable contributor: iron deficiency, vitamin B12 deficiency, thyroid dysfunction, poorly controlled diabetes, dyslipidaemia, or anaemia. Correcting these does not always cure tinnitus, but commonly reduces its severity.
Causes of Tinnitus
Tinnitus has a broad differential. These are the causes most relevant to a blood test workup, plus the structural and vascular causes that require imaging.
Iron deficiency (low ferritin)
Reduced oxygen delivery to the cochlea and auditory nerve impairs the high metabolic demands of inner-ear hair cells. Ferritin below 30 mcg/L can cause tinnitus even when haemoglobin is still normal.
Vitamin B12 deficiency
B12 is essential for myelin production in the auditory nerve. Deficiency causes demyelination that disrupts auditory signal transmission. Multiple studies show elevated tinnitus rates in B12-deficient patients.
Folate deficiency
Folate works synergistically with B12 in homocysteine metabolism. Elevated homocysteine (from folate or B12 deficiency) is directly ototoxic and damages cochlear microcirculation.
Vitamin D deficiency
Vitamin D receptors are present in cochlear tissue. Deficiency is associated with otosclerosis (abnormal bone remodelling in the middle ear) and may impair the vascular supply to the inner ear.
Hypothyroidism
Underactive thyroid causes fluid accumulation in the middle ear, reduces cochlear blood flow, and slows myelin maintenance. TSH elevation is a standard finding in the tinnitus workup.
Hyperthyroidism
Excess thyroid hormone increases cardiac output and blood flow velocity, causing pulsatile tinnitus from turbulent flow near the ear. Also directly affects cochlear metabolism.
Anaemia (any cause)
Low haemoglobin reduces oxygen delivery to the inner ear. The heart compensates by beating faster and harder, increasing blood flow turbulence that can be perceived as pulsatile tinnitus.
Uncontrolled hypertension
High blood pressure increases turbulent flow in vessels near the cochlea and accelerates atherosclerosis of cochlear arteries. Poorly controlled hypertension is one of the most modifiable tinnitus risk factors.
Diabetes (microvascular)
Chronic hyperglycaemia damages small blood vessels, including the cochlear microvasculature. Diabetic cochlear angiopathy is analogous to diabetic retinopathy and nephropathy and can cause both tinnitus and sensorineural hearing loss.
High cholesterol (dyslipidaemia)
Elevated LDL and triglycerides accelerate atherosclerosis of cochlear arterioles, reducing blood supply to the sensory hair cells. A fasting lipid panel is standard in the workup.
TMJ (jaw joint) dysfunction
The temporomandibular joint sits adjacent to the ear canal. Dysfunction causes referred sensations that can present as tinnitus, ear fullness, or clicking. Diagnosed clinically, not by blood test.
Otosclerosis
Abnormal bone remodelling of the middle ear ossicles. Associated with vitamin D deficiency and hyperthyroidism. Causes conductive hearing loss and tinnitus. Diagnosed by audiometry and CT.
Autoimmune (lupus, vasculitis)
Autoimmune vasculitis can affect cochlear blood vessels. Sudden sensorineural hearing loss with tinnitus in a young person warrants ANA and ANCA testing alongside the standard panel.
Hyperviscosity (high haematocrit, polycythaemia)
Thick, viscous blood flows sluggishly through cochlear capillaries. Polycythaemia vera and dehydration both reduce inner-ear perfusion. FBC with haematocrit is part of the standard workup.
Ototoxic medications
Aspirin (high dose), NSAIDs, aminoglycoside antibiotics, loop diuretics, quinine, and cisplatin all damage hair cells. This is medication-related and diagnosed from history, not blood test.
Blood Tests for Tinnitus
This panel covers the modifiable blood-testable causes. All are bulk billed in Australia with a GP referral (vitamin D requires a clinical indication — tinnitus qualifies).
| Test | Why It Is Ordered | Typical Australian Range |
|---|---|---|
| Full Blood Count (FBC) | Screens for anaemia, polycythaemia, infection | Hb 115-165 g/L (women), 130-175 g/L (men) |
| Ferritin | Iron stores — most sensitive early iron deficiency marker | 30-300 mcg/L (optimal >50 mcg/L) |
| Transferrin saturation | Confirms iron deficiency when ferritin is borderline | 20-45% |
| Vitamin B12 | Auditory nerve myelin maintenance | 150-700 pmol/L (optimal >300) |
| Folate | Homocysteine metabolism, cochlear protection | 7-45 nmol/L |
| Vitamin D (25-OH) | Cochlear health, otosclerosis risk | Optimal 75-150 nmol/L |
| TSH | Thyroid screen — both hypo and hyperthyroid affect the ear | 0.4-4.0 mIU/L |
| Free T4 | Confirms thyroid dysfunction if TSH abnormal | 9-19 pmol/L |
| HbA1c | Diabetes control and cochlear microvascular risk | Below 48 mmol/mol (6.5%) |
| Fasting lipids (LDL, HDL, TG) | Cochlear atherosclerosis risk | LDL below 2.0 mmol/L (high-risk), HDL above 1.0 |
| eGFR + creatinine | Kidney disease associated with tinnitus (shared vascular risk) | eGFR above 60 mL/min/1.73m² |
| ESR + CRP | Inflammation and autoimmune screening | CRP below 5 mg/L, ESR below 20 mm/hr |
| ANA (if other autoimmune symptoms) | Lupus, vasculitis, autoimmune inner-ear disease | Negative or low titre |
How Your GP Will Investigate Tinnitus
Characterise the tinnitus
Your GP will ask: Is it in one ear or both? Is it constant or intermittent? Does it pulse with your heartbeat (pulsatile) or is it a steady tone/noise? Any associated hearing loss, vertigo, or ear fullness? How long has it been present? Any noise exposure? Any new medications? These answers guide urgency and investigation pathway.
Blood panel for modifiable causes
The full blood count, ferritin, B12, folate, vitamin D, TSH, HbA1c, and fasting lipids form the core modifiable-cause screen. All are bulk-billed in Australia. This panel takes one blood draw and identifies the most treatable causes.
Blood pressure measurement
Hypertension is one of the most common and modifiable contributors to tinnitus. Your GP will check blood pressure at the appointment; home readings over 1 week provide more accurate assessment than a single clinic reading.
Audiometry (hearing test)
A formal hearing test (audiogram) identifies sensorineural hearing loss that often coexists with tinnitus and influences management. Most ENT and audiology practices can arrange this; some GPs refer directly from the initial appointment.
Specialist referral for red-flag patterns
Unilateral tinnitus, pulsatile tinnitus, sudden hearing loss, or tinnitus with vertigo warrant ENT referral. MRI of the internal auditory canals is performed to exclude acoustic neuroma (vestibular schwannoma) and other structural causes.
Address modifiable risk factors
If blood tests reveal iron deficiency, B12 deficiency, hypothyroidism, uncontrolled diabetes, or dyslipidaemia — treating the underlying condition often reduces tinnitus severity, sometimes substantially. This is why the blood workup is worth doing even when tinnitus seems established.
Red Flags — When Tinnitus Needs Urgent Assessment
Most tinnitus can wait for a routine GP appointment. These patterns cannot:
Unilateral tinnitus (one ear only)
Tinnitus in only one ear raises concern for acoustic neuroma (vestibular schwannoma) — a slow-growing benign tumour on the auditory nerve. Most are benign but require MRI to exclude. Do not dismiss unilateral tinnitus as "just stress".
Pulsatile tinnitus (beats with heartbeat)
Pulsatile tinnitus indicates a vascular source — turbulent blood flow near the ear. Causes range from benign (anaemia, high blood pressure) to serious (arteriovenous malformation, dural arteriovenous fistula, jugulotympanic paraganglioma). Always needs imaging.
Sudden onset tinnitus with hearing loss
Sudden sensorineural hearing loss is a medical emergency. High-dose oral or intratympanic corticosteroids within 24-72 hours significantly improve the chance of hearing recovery. Do not wait for a routine appointment.
Tinnitus + vertigo + hearing loss
This triad is the classic presentation of Meniere's disease. The condition involves abnormal fluid pressure in the inner ear and requires specialist management including dietary modification, diuretics, and sometimes surgical intervention.
Tinnitus after head injury
Post-traumatic tinnitus can indicate perilymphatic fistula (tear in the inner-ear membrane), temporal bone fracture, or acoustic nerve injury. Needs imaging and ENT assessment urgently.
What to Say to Your GP
A focused referral request for the tinnitus blood panel gets better results than a vague complaint. Try this approach:
“I've had tinnitus in [both/my left/my right] ear for [duration]. It is [constant/intermittent] and [does/does not] pulse with my heartbeat. I'd like to check whether there are any blood-testable causes — specifically iron stores (ferritin), B12, vitamin D, thyroid, HbA1c, and a fasting lipid panel. I've read these are worth checking before assuming it is noise-related.”
Lifestyle Measures and Management
Protect from further noise damage
Noise-induced hearing loss amplifies tinnitus. Wear hearing protection at concerts, on the shooting range, or using power tools. The 60/60 rule for headphones: no more than 60% volume for 60 minutes at a time.
Reduce caffeine and salt
Both caffeine and excess dietary sodium increase tinnitus perception in some patients. A 4-week trial of reduction is low-risk and sometimes produces meaningful improvement, especially in Meniere's-pattern tinnitus.
Sound therapy at night
A fan, white noise machine, or soft music prevents the brain from focusing on tinnitus in a quiet bedroom. This is well-supported in tinnitus management guidelines and significantly improves sleep quality for most patients.
Manage stress and anxiety
Stress and anxiety amplify tinnitus perception through sympathetic nervous system activation. Mindfulness-based stress reduction (MBSR) has moderate evidence for tinnitus and is widely available in Australia.
Review medications with your GP
High-dose aspirin, ibuprofen, and some antibiotics are directly ototoxic. Do not stop prescribed medications without GP advice, but a review is worthwhile if tinnitus started after a medication change.
Avoid complete silence
The brain fills silence with generated noise. Habituating to tinnitus is easier with background sound. Tinnitus retraining therapy (TRT) and cognitive behavioural therapy (CBT) are the most evidence-based psychological approaches.
Related Reading
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This page provides general educational information about tinnitus and its blood-testable causes. It is not a substitute for professional medical advice, diagnosis, or treatment. Unilateral tinnitus, pulsatile tinnitus, and sudden hearing loss require prompt specialist assessment. SmarterBlood does not provide medical care.