Symptoms
Tingling and Numbness: Which Blood Tests to Check First
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed August 20267 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
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Persistent pins and needles usually points to the nerves. The blood tests checked first are vitamin B12, blood sugar (HbA1c) for diabetes, and thyroid function. Too much vitamin B6 from supplements can do the same thing, and it gets missed. Numbness that arrives suddenly, especially on one side, is different and needs urgent care.
Not sure which markers you need? Build your test →Tingling and numbness are the language of irritated nerves. A short-lived patch after sitting awkwardly is nothing. What is worth looking into is the slow creep of numbness in the toes or fingertips that does not settle.
That pattern is called peripheral neuropathy. Several of its common causes are treatable, and catching one early gives the nerves the best chance to recover.
Seek urgent help if numbness or weakness comes on suddenly, especially on one side of the body, the face droops, or speech is slurred. These can be signs of a stroke. Call 999. Numbness with loss of bladder or bowel control, or after a significant injury, also needs emergency care.
1. When is tingling worth checking?
Most tingling is harmless and passes. A hand that has gone to sleep, a foot that needs shaking out. The kind worth investigating is persistent and unexplained, and it tends to follow a pattern. It usually starts in the toes or fingertips and spreads slowly. Doctors call that a glove-and-stocking distribution.
It is more common than most people expect. The NHS estimates that almost 1 in 10 people aged 55 or over in the UK are affected by peripheral neuropathy.
That symmetrical, gradual pattern points towards the causes a blood test can find, rather than a trapped nerve in one spot.
2. What does the NHS check first for peripheral neuropathy?
A GP starts with your history and an examination of sensation, strength and reflexes. Bloods come next, and the NHS is specific about what they are looking for.
“The GP may also arrange blood tests, especially to check for causes such as diabetes or vitamin B12 deficiency.”
– NHS, Peripheral neuropathy: Diagnosis
Those two come first for a reason. The NHS also says that in the UK, diabetes is the most common cause of peripheral neuropathy. Low vitamin B12 is the other cause that is both common and fixable. The wider B12 symptom list is worth reading beside this one.
Fixable does not mean a shop-bought jab. Our guide to B12 injections in the UK explains why the blood test has to come before the injection, and what a low result needs next.
Thyroid function is a frequent third check, and a GP may add a full blood count and kidney function to see the wider picture. If nothing shows up, the next step is usually a neurologist and nerve conduction studies, which measure how fast your nerves carry a signal. No blood test can do that part.
3. Which blood tests to consider
For persistent, symmetrical tingling, this is the set usually considered. Read together rather than one at a time, they cover most of the checkable causes.
| Marker | What it shows | Where we report it |
|---|---|---|
| Vitamin B12 | Nerves need it for their protective coating. | General Energy & Wellness, Vitamins & Minerals |
| Folate | Works alongside B12, so it is read next to it. | Vitamins & Minerals |
| HbA1c | Average blood sugar over two to three months. | Advanced Heart Health |
| TSH and Free T4 | Thyroid function. An underactive thyroid can tingle. | General Energy & Wellness, Thyroid & Vital Organs |
| Urea and creatinine | Kidney function, another cause of nerve symptoms. | General Energy & Wellness, Thyroid & Vital Organs |
| Vitamin B6 | Too much of it damages sensory nerves. | Not part of any Helvy test. Ask your GP. |
| Full blood count | Anaemia, and the size of your red cells. | Not part of any Helvy test. Ask your GP. |
No single Helvy kit carries every row. The last column says which panel holds what. Our full blood count guide explains the one we do not offer, so you know what to ask for.
4. Vitamin B12 deficiency
Vitamin B12 builds the protective sheath around your nerves, so running low on it is a classic cause of tingling. It is also one of the treatable ones. Left alone for long enough it can cause lasting nerve damage, which is why it sits so high on the list.
“Vitamin B12 deficiency can also cause symptoms that affect your brain and nervous system”, with the list including “pins and needles” and “numbness”.
– NHS, Vitamin B12 or folate deficiency anaemia
Low B12 is more likely with age, on a plant-based diet, and where your gut absorbs less than it should. Our vitamin B12 blood test guide covers how it is measured, and B12 levels by age covers the grey zone where symptoms appear at low-normal numbers. Folate has a grey zone of its own, set out in normal folate levels. If you take a daily reflux tablet, see what long-term omeprazole does to B12 and magnesium.
5. Diabetes and blood sugar
High blood sugar damages the small nerves over time. That is diabetic neuropathy, and it is the single most common cause of numb feet in the UK. It can be the symptom that leads to the diagnosis, and it can start during the pre-diabetes stage, before anyone has used the word diabetes.
HbA1c is the test. It reports your average blood sugar over the past two to three months, so a single bad breakfast does not move it. The diabetes blood test guide and the HbA1c guide explain the ranges and where pre-diabetes sits.
6. Too much vitamin B6
This is the one that catches people out. Low B12 causes tingling. So does too much vitamin B6, almost always from high-dose supplements taken over months. It damages the sensory nerves and produces the same pins and needles. Supplements feel harmless, so nobody thinks to check.
If you take a B-complex or a high-strength B6 and the tingling is new, read the dose on the label first. We do not measure B6, so this is a GP conversation. Our vitamin B6 blood test guide sets out the UK supplement guidance and the toxicity risk.
A different B vitamin is sold the other way round, as a fix for tingling rather than a cause of it. The evidence on benfotiamine, the fat-soluble form of vitamin B1, came back flat in a 12-month trial published in 2026.
7. Thyroid, kidneys and trapped nerves
An underactive thyroid can cause tingling, and it sits behind some carpal tunnel symptoms, so a thyroid test is usually included. Reduced kidney function, low folate, heavy alcohol use and certain medicines can all contribute too.
Not every cause shows up in blood. A trapped nerve, such as carpal tunnel syndrome in the wrist, is a mechanical problem, and no blood test will find it. That is why a hands-on assessment matters alongside any testing. If the tingling comes with exhaustion that sleep does not fix, our energy and fatigue hub covers the markers that move together.
8. GP or private test?
Persistent numbness deserves a GP visit. You want the bloods, and you want someone to examine the nerves, because some causes need that hands-on assessment. A GP will typically check B12, HbA1c and thyroid first.
A private test gives you a fuller set of numbers to bring to that conversation. It complements a clinical assessment rather than replacing one, especially if symptoms are getting worse.
CHECK THE TREATABLE CAUSES
Bring numbers to your GP, not just symptoms.
Our General Energy & Wellness panel reports vitamin B12 with thyroid and kidney markers. Vitamins & Minerals covers B12 with folate and iron. Both are home finger-prick kits, analysed at UKAS-accredited UK laboratories, with qualified clinician review.
9. Frequently asked questions
What blood tests does the NHS do for peripheral neuropathy?
The NHS says a GP may arrange blood tests to check for causes such as diabetes or vitamin B12 deficiency. Thyroid function, a full blood count and kidney function are common additions. If those come back clear, the next step is usually a neurologist.
What blood tests are done for tingling and numbness?
Vitamin B12 and folate, HbA1c for diabetes, thyroid function, vitamin B6 if you take supplements, and a full blood count with kidney function for context. Together they cover most of the causes a blood test can find.
Can a blood test show nerve damage?
No. Blood tests look for the causes behind nerve symptoms, not the damage itself. Measuring the nerves takes nerve conduction studies or electromyography, both done in hospital. A blood test is the first step, not the whole answer.
Can low B12 cause tingling and numbness?
Yes. B12 builds the protective sheath around nerves, and low levels are a classic, treatable cause of pins and needles. Left unaddressed it can cause lasting nerve damage, so it gets checked early.
Can vitamin B6 supplements cause tingling?
Yes, and it surprises people. High-dose B6 taken over months can damage the sensory nerves and cause tingling. If you take a B-complex or a high-strength B6 and symptoms are new, check the dose and speak to a clinician.
When should I worry about numbness?
Seek urgent help if numbness or weakness comes on suddenly, especially on one side, with face drooping or slurred speech. These can be signs of a stroke. Call 999. Numbness with loss of bladder or bowel control, or after a significant injury, also needs emergency care.
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