Understand a result, in plain English

A number on a letter or in the NHS App can be worrying when nobody has explained it yet. These tools put it in context, using the ranges NHS and NICE guidance use, so you know what to ask next.

The plan, in 5 steps

  1. 1Blood pressure
  2. 2HbA1c (blood sugar)
  3. 3Cholesterol
  4. 4Kidney function (eGFR)
  5. 5Not sure where to go?

Step by step

Find your result

Choose the one that matches your letter or app. Each explains the usual ranges, converts units and says when to speak to someone.

  1. Blood pressure

    Ideal is roughly 90/60 to 120/80. A clinic reading of 140/90 or more, or 135/85 at home, is usually considered high and worth a follow up.

    Open the blood pressure explainer

  2. HbA1c (blood sugar)

    Shows your average blood sugar over two to three months. Under 42 mmol/mol is the usual range; 42 to 47 is sometimes called prediabetes; 48 or more can mean diabetes.

    Open the HbA1c converter

  3. Cholesterol

    Your total to HDL ratio, alongside the ranges on most results. Lower ratios are better, and your GP will look at it with your other risk factors.

    Open the cholesterol ratio calculator

  4. Kidney function (eGFR)

    eGFR estimates how well your kidneys filter. A result over 90 is usual; one low result is common and often repeated before anything is decided.

    Open the eGFR calculator

  5. Not sure where to go?

    Pharmacy, GP, 111 or A&E? This helps you choose the right service for how you feel right now.

    Open the 111 or 999 chooser

Reading a result

Five things worth knowing

  • Ranges are not cliffs. A result just outside the range is often fine, and labs mark them so a clinician can look.
  • One number is a snapshot. Many tests, like blood pressure and kidney function, are repeated before a decision is made.
  • Units matter. UK labs usually use mmol/L and mmol/mol, while many websites use mg/dL or percentages. The converters here help.
  • Context matters more. Your age, medicines and history change what a result means.
  • "Satisfactory, no action" usually means exactly that. If you are unsure, it is fine to ask.

What to ask

Questions for your GP or nurse

If a result has been flagged, you will usually be contacted. If you have seen it first in the NHS App, it can help to write a few questions down before you call.

  • What does this result mean for me?
  • Does it need repeating, and when?
  • Is there anything I can do in the meantime?
  • Do any of my medicines need changing?
  • When should I get in touch sooner?

Urgent help

When not to wait

Results come and go, but symptoms matter now. Call 999 for chest pain, sudden weakness on one side, difficulty speaking or severe breathlessness. Use NHS 111 if you feel unwell and are not sure what to do.

Questions

Common questions

Where can I see my test results?

In England, many GP results appear in the NHS App, sometimes before your GP has looked at them. Scotland, Wales and Northern Ireland have their own apps and services. If a result worries you, contact your surgery.

What does a "normal range" mean?

It is the range that about 95 out of 100 healthy people fall into. That means some healthy people sit just outside it, which is why one result is rarely the full story.

My blood pressure was high at the surgery. Is it really high?

Maybe not. Many people read higher in a clinic. NICE recommends checking with home or 24 hour monitoring before diagnosing high blood pressure.

What is prediabetes?

An HbA1c of 42 to 47 mmol/mol means a higher chance of type 2 diabetes. It is a warning, not a diagnosis, and many people bring it down with changes to food and activity. You may be offered the NHS Diabetes Prevention Programme.

Can these tools diagnose anything?

No. They explain the usual ranges and convert units. Only a clinician who knows your history can tell you what a result means for you.

Sources

Last checked 21 October 2026. Every calculator on this page links to its own sources too. More in Health checks.

Ask, it is your result

If a result worries you, or you do not understand a letter, contact your GP surgery. It is your result and you are entitled to ask about it. For sudden or severe symptoms, call 999.

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