What Are The Different Types of Neurological Blood Tests? All you need to know.

Blood tests have long held a peripheral presence in neurological diagnostics, overshadowed by MRIs, CTs, and EEGs that seemingly ‘see’ the brain. Yet these tests reveal the undercurrents influencing nerve health and brain function. Neurological blood tests are important in unravelling causes hidden in vitamins, immune responses, toxins, or systemic imbalances.  

For anyone experiencing consistent numbness, unexplained weakness, cognitive lapses, or tingling sensations, these tests can frame the first step towards clarity. While they rarely diagnose a neurological disorder outright, their role in building differential diagnoses remains indisputable. 

Types of Neurological Blood Tests 

The following list of blood tests is used to assess brain function, nerve damage, and overall neurological health. This neuro profile blood test compilation is neither exhaustive nor universally prescribed, but remains representative of standard clinical approaches. 

Complete Blood Count (CBC) 

CBC measures red blood cells, white blood cells, haemoglobin, and platelets. Anaemia results in reduced oxygen supply to the brain. It can detect dizziness or cognitive slowing. High levels of white cells indicate infection (systemic or neurological) in its effects. Though a basic test, its absence in neurological evaluation makes the assessment incomplete. 

Comprehensive Metabolic Panel (CMP) 

CMP includes glucose, electrolytes, kidney, and liver parameters. Electrolyte imbalances such as hyponatraemia (low sodium) alter neuronal firing and brain messages. High creatinine and BUN levels point to kidney dysfunction is a known contributor to neuropathy. High glucose indicates diabetes, which is the most common cause of peripheral neuropathy globally. It affects small fibres and later large fibres when undiagnosed. 

Thyroid Function Tests (TSH, T3, T4) 

Thyroid hormones influence nerve metabolism and synaptic transmission. Hypothyroidism is linked to delayed reflexes, cognitive dulling, neuropathies with numbness or tingling. Hyperthyroidism can cause tremors, restlessness, and nerve excitability. Testing is essential in neuropathy screening panels. 

Vitamin B12 and Folate Levels 

Vitamin B12 deficiency leads to demyelination of nerves and results in sensory loss, weakness, ataxia, or cognitive decline. Folate influences homocysteine metabolism, affecting vascular and neuronal health. High B6, paradoxically, is neurotoxic. Testing for these vitamins forms the core of a blood test for nerve damage workup. 

Tests for Metals and Minerals 

Lead, arsenic, mercury, and thallium are toxic to nerves. Excess exposure results in neuropathies marked by sensory deficits and weakness. Copper deficiencies are rare but can lead to myelopathy with gait disturbance. Metal testing is a targeted neuro profile blood test rather than a routine screen. 

Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) 

These inflammatory markers are high in autoimmune disorders like vasculitis or rheumatoid arthritis with neurological manifestations. ESR measures red cell aggregation while CRP rises in acute inflammation. High values need further immunological investigations. 

Antinuclear Antibodies (ANA) and Autoimmune Panels 

ANA positivity suggests systemic lupus erythematosus, Sjögren’s syndrome, or other autoimmune conditions. Anti-Ro (SS-A) and Anti-La (SS-B) are specific to Sjögren’s. These antibodies correlate with neuropathies ranging from sensory neuronopathy to small fibre neuropathy. 

Tests for Infections 

• HIV Testing: Neuropathy is common in HIV, either due to the virus or certain antiretrovirals. Early detection improves outcomes. 
• Lyme Antibodies Testing: Lyme disease causes radiculopathies and peripheral neuropathy. Antibody testing confirms diagnosis in endemic areas. 
• Hepatitis C Antibodies: Linked to cryoglobulinemia-induced neuropathies. Positive antibodies are confirmed by HCV RNA testing. 

Tests for Blood and Bone Marrow Disorders 

Serum Protein Electrophoresis (SPEP) and Serum Free Light Chains: Detect monoclonal gammopathies (multiple myeloma, MGUS, Waldenström’s macroglobulinemia) causing neuropathy. These tests do not examine nerves directly but reveal systemic causes damaging them. 

Oral Glucose Tolerance Test 

The gold standard for diagnosing diabetes and pre-diabetes. High glucose levels impair nerve vascularisation, leading to diabetic neuropathy. While HbA1c reflects average glucose, OGTT captures impaired tolerance missed by fasting tests. 

Genetic Testing 

Performed in suspected hereditary neuropathies like Charcot-Marie-Tooth disease. This test identifies specific mutations that aid counselling and anticipatory care. 

Neurofilament Light Chain (NfL) and Emerging Biomarkers 

NF-L is released upon neuronal damage, is high in ALS, multiple sclerosis, and neurodegenerative diseases. It remains a research-to-clinical translation area but represents the evolving frontier of blood tests for brain function. 

Conclusion 

Neurological blood tests may look routine, but they are important for diagnosing, managing, and predicting diseases. They help connect a patient’s symptoms with possible causes like metabolic problems, infections, or autoimmune conditions. 

At Hinduja Hospital Mahim, our neurology team uses these tests judiciously within your diagnostic pathway to ensure accurate, comprehensive care. If you are experiencing persistent neurological symptoms like tingling, weakness, unexplained fatigue, or cognitive changes, consult our specialists for a thorough evaluation and appropriate testing.  

Frequently Asked Question (FAQs) 

What blood tests show neurological issues? 

Blood tests that check Vitamin B12, thyroid hormones, and blood sugar levels can help find the causes of neurological problems. Other tests include markers for inflammation, autoimmune diseases, and toxins that may affect nerves. 

Can CBC detect neurological problems? 

A CBC does not directly detect neurological problems, but it can show anaemia, infections, or inflammation that might affect brain or nerve function.