Heart health
Blood tests for high blood pressure: what your results mean
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed October 20266 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.
QUICK ANSWER
NICE says everyone with high blood pressure should be offered a blood test for kidney function (creatinine and eGFR), blood sugar (HbA1c), salts and cholesterol, plus a urine test. A 2026 UK study found the strongest evidence for two of them: eGFR, which reads your kidneys, and HbA1c, which checks for diabetes.
Not sure which markers you need? Find my test →The cuff read high, so the nurse booked you in for bloods. Now a row of results sits in the NHS App with words like eGFR and HbA1c beside them. Most say normal. One or two might not.
As of October 2026, a UK review in the British Journal of General Practice has asked which of those tests actually help. This guide walks through each result, what it is looking for and how to read your number.
1. Why does high blood pressure need a blood test?
A blood test cannot measure your blood pressure. That is the cuff’s job. The NHS counts 140/90 or higher at the surgery, or 135/85 or higher at home, as high.
The bloods answer a different question. Is the pressure already straining your kidneys? Is diabetes or high cholesterol travelling with it? Each of those raises the risk of a heart attack or stroke. Together they shape the advice and treatment you are offered.
Kidneys are the main worry. They filter blood through millions of tiny vessels, and years of high pressure can scar them. Damaged kidneys then struggle to control salt and water, which can push the pressure higher still.
“Take a blood sample to measure glycated haemoglobin (HbA1C), electrolytes, creatinine, estimated glomerular filtration rate, total cholesterol and HDL cholesterol.”
NICE guideline NG136, Hypertension in adults, recommendation 1.3.3
2. Which tests will your GP offer?
The NICE list is short. Here is what each test looks at, in plain words.
| Test | What it is looking for |
|---|---|
| eGFR and creatinine | How well your kidneys filter your blood |
| HbA1c | Your average blood sugar over two to three months |
| Electrolytes | Sodium and potassium, the salts that some pills shift |
| Total and HDL cholesterol | Fats that feed your heart and stroke risk score |
| Urine ACR | Protein leaking into urine, an early kidney sign |
NICE also asks for an eye check and a heart tracing (an ECG). The blood part is often reported as a U&E, short for urea and electrolytes, with HbA1c and cholesterol beside it.
3. Which results matter most?
Two of them. A UK team looked at the 16 tests UK practices routinely order for high blood pressure. Their study appeared in the British Journal of General Practice in July 2026.
They found consistent, good evidence for eGFR, to spot kidney disease, and HbA1c, to spot diabetes. Their minimal panel also keeps potassium and sodium, which matter most if you take certain blood pressure pills.
Why the salts? Common pills such as ramipril and losartan can raise potassium. Water tablets can lower sodium. So if you start one of those, expect a repeat blood test within a few weeks.
Cholesterol was a surprise. The team found no clear proof that re-checking it routinely helps. It still feeds the heart risk score NICE uses, so your first result counts.
4. How do you read your eGFR?
eGFR, short for estimated glomerular filtration rate, is a guess at how much blood your kidneys clean each minute. It is worked out from creatinine, a waste product your muscles make and your kidneys clear. Higher eGFR means better filtering.
90 or above is normal. It drifts down with age, so a reading in the 70s is common past 60. Our eGFR by age table shows what is typical for you.
Under NICE’s kidney guideline, a result below 60 that lasts over three months points to chronic kidney disease. One low reading is not enough. A low eGFR is always repeated, because a big meat meal or dehydration can push it down for a day.
5. How do you read your HbA1c?
HbA1c shows how much sugar has stuck to your red blood cells. Those cells live about three months, so it gives a long average rather than a snapshot. You do not need to fast for it.
- Below 42 mmol/mol is the normal range.
- 42 to 47 is the warning band, often called prediabetes.
- 48 or above is in the diabetes range.
High blood pressure and raised blood sugar often turn up together. Our normal HbA1c levels guide explains what a 39 or a 44 really means.
6. What does your cholesterol result tell you?
On its own, not much. Your GP feeds total and HDL cholesterol into a risk score called QRISK, along with your age, blood pressure and smoking. The score, not the single number, guides the next step.
HDL is the “good” cholesterol that carries fat away from your arteries, so higher is better there. Our cholesterol blood test guide covers each line on the report.
7. What if a result is outside the range?
Do not panic, and do not ignore it. A single flagged number is a prompt to look again, not a verdict. Kidney and sugar results are usually repeated before anything changes.
Keep a copy of every result. The trend over a year tells a qualified clinician far more than one reading does. If your eGFR or HbA1c is moving the wrong way, that is the conversation to have.
8. What does Helvy measure, and what does it not?
The Thyroid & Vital Organs panel (£159) reads your kidneys: eGFR, creatinine and urea. It adds a full cholesterol profile, liver markers and thyroid.
The Advanced Heart Health panel (£159) reads HbA1c with the full cholesterol profile. It adds ApoB, a count of the particles that carry cholesterol into artery walls, and Lp(a), an inherited risk marker.
We do not test sodium, potassium or urine ACR, and we do not take your blood pressure. If you take a blood pressure pill, ask your GP for those. A home cuff is the best way to track the pressure itself.
A blood test measures biomarkers. It offers wellness insight rather than a diagnosis. Not sure which panel fits? The Find my test tool takes a couple of minutes, and the heart health hub has the rest of our guides.
READY TO TEST?
Ask your blood
Helvy’s home blood tests report your kidney, blood sugar and cholesterol markers with plain-English context. Samples are processed by UKAS-accredited UK labs.
Frequently asked questions
What blood tests are done for high blood pressure?
NICE recommends HbA1c, electrolytes, creatinine, eGFR, total cholesterol and HDL cholesterol. It adds a urine test for protein and blood, an eye check and an ECG.
Can a blood test show high blood pressure?
No. Only a cuff measures blood pressure. The bloods check whether your kidneys are under strain and whether diabetes or high cholesterol are adding to your heart risk.
Which blood tests matter most with high blood pressure?
A 2026 study in the British Journal of General Practice found the strongest evidence for eGFR, to spot kidney disease, and HbA1c, to spot diabetes. It also kept potassium and sodium for people on certain pills.
Does high blood pressure affect eGFR?
It can, over years. That is why eGFR is checked. A result below 60 that lasts over three months points to chronic kidney disease, so one low reading is always repeated before anyone reads much into it.
Do I need to fast for blood pressure blood tests?
Usually not. HbA1c, eGFR and a standard cholesterol test do not need fasting. Avoid a large meat meal the night before, as it can nudge creatinine up and eGFR down.
Related guides
eGFR Levels by Age
What a normal kidney score looks like at 40, 60 and 80.
Normal HbA1c Levels
Where your blood sugar sits inside the normal band.
U&E Results Explained
Sodium, potassium, urea and creatinine, line by line.
Cholesterol Blood Test
Every number on a cholesterol report, read plainly.
Kidney Function Test
How kidney blood tests work and when to repeat one.
Heart Health Hub
Every guide we have written on heart risk and testing.