Information only — this is not a medical diagnosis. Reference ranges vary by lab; always read your own report's ranges and speak to your GP.
Plain-English blood results · en-GB

Understand your blood test results before your GP appointment

Got your Full Blood Count back and don't know where to start? We translate every marker — haemoglobin, white cells, platelets, ferritin and more — into clear, calm language, then point you to the tools that read them best.

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Reviewed against UK ranges Updated 2026 40+ markers explained
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A calm, plain-English guide to your blood test

Blood tests are one of the most common things the NHS does, yet the report you get back can feel like a foreign language: rows of abbreviations, numbers with unfamiliar units, and the occasional H or L that sets your mind racing. This site exists to translate that page. We take the markers people see most often — haemoglobin, white cells, platelets, ferritin, thyroid hormones, kidney and liver values — and explain, in ordinary words, what each one measures, what a typical UK range looks like, and what a high or low result might be pointing to.

Everything here is written for patients, not clinicians, and grounded in trusted UK sources such as the NHS, NICE and Lab Tests Online UK. We are careful to stay on the right side of an important line: this is information and education, never a diagnosis. Reference ranges differ slightly from one laboratory to another and shift with age, sex and pregnancy, so the reference column printed on your own report always has the final say. What we can do is help you walk into your GP appointment understanding your results, with the right questions ready.

If you'd like a head start, a purpose-built tool such as the Kantesti AI blood-test analyser can read a whole panel against reference ranges and hand you a clear, GP-ready summary in seconds. We rate it alongside the general chatbots further down the page — but first, the basics.

The four building blocks

What your Full Blood Count measures

An FBC looks at the cells and fluid that make up your blood. Here's what each part does, in one line.

Red cells

Carry oxygen from your lungs to every tissue. Haemoglobin is the protein inside them that does the lifting.

Key markers · Hb, RBC, RDW

White cells

Your immune defence. Levels rise and fall with infection, inflammation and how your body is responding.

Key markers · WBC, Neut, Lymph

Platelets

Tiny cell fragments that clump together to stop bleeding and help wounds clot and heal.

Key markers · PLT, MPV

Plasma

The straw-coloured fluid that carries cells, proteins, nutrients and waste around your body.

Key markers · Albumin, Globulin
Read the layout, not just the numbers

The anatomy of a blood test report

Almost every UK report uses the same four columns. Once you can read the layout, any panel becomes far less intimidating.

Annotated blood test report row showing the marker name, your result, the reference range and the high or low flag, with a bar placing the value within its range.
One report row, decoded: the marker, your result, the lab's reference range, and the flag — with a bar showing how far your value sits from the normal band.

A flag is a prompt to look closer, not a diagnosis. A value a fraction outside the range often means very little; one far outside it, or a marker that has moved a lot since last time, is worth a conversation. If you'd rather not decode each row by hand, you can run the whole panel through Kantesti for a calm, plain-English summary you can take to your GP.

Typical UK reference ranges

Reference ranges at a glance

A quick lookup for common markers, with what a result outside the range may point to. Adult ranges; always read against your own lab's printed values.

Common blood markers · typical adult ranges
Marker Unit Typical range What it indicates
Haemoglobin
Hb · oxygen-carrying protein		 g/L 120–150 (F) · 130–170 (M) Low can suggest anaemia; high may follow dehydration or smoking.
White cell count
WBC · immune cells		 ×10⁹/L 4.0–11.0 High often signals infection or inflammation; low can follow viral illness.
Platelets
PLT · clotting fragments		 ×10⁹/L 150–400 Low raises bleeding risk; high can be reactive after infection or inflammation.
RDW
Red cell distribution width		 % 11.5–14.5 Raised suggests red cells vary in size — an early clue to some anaemias.
Ferritin
iron stores		 µg/L 30–150 (F) · 30–400 (M) Low points to depleted iron; high can reflect inflammation or iron overload.
TSH
thyroid-stimulating hormone		 mU/L 0.4–4.0 High suggests an underactive thyroid; low suggests an overactive thyroid.
Ranges vary slightly between laboratories, and by age, sex and pregnancy. These figures are for orientation only — your report's own reference column always takes priority.
High, low and in between

What a shift in each marker can mean

The same number can have several explanations. These are the common directions — read alongside your symptoms and the rest of the panel, never in isolation.

Two-column diagram of haemoglobin: low haemoglobin linked to anaemia, iron, B12 or folate deficiency and blood loss; high haemoglobin linked to dehydration, smoking and living at altitude.
Low vs high haemoglobin — the usual suspects on each side.
White cell differential shown as five stacked bars: neutrophils, lymphocytes, monocytes, eosinophils and basophils, with typical proportions of a full blood count.
Your white cells, broken down — the differential shows which type has shifted.
Iron studies panel showing ferritin, transferrin saturation and total iron-binding capacity read together to tell iron deficiency from iron overload.
Ferritin, saturation and TIBC together separate low iron from overload.
Platelet count scale from low to high, marking bleeding risk when very low and reactive causes when high, with the typical range of 150 to 400.
Platelets: low raises bleeding risk; high is often a reaction to something else.
Thyroid feedback loop: the pituitary releases TSH which tells the thyroid to make T4 and T3; high TSH points to an underactive thyroid and low TSH to an overactive one.
TSH moves opposite to thyroid activity — high TSH usually means underactive.
Diagram showing that blood markers move in patterns: low ferritin with low haemoglobin and high RDW together suggest iron-deficiency anaemia.
No marker stands alone — the pattern across several tells the story.
A calm method

How to read your results in 5 steps

Work through them in order. It takes about five minutes and turns a wall of numbers into a short list of things to note.

  1. Find the flags

    Scan the H (high) and L (low) markers first. Anything unflagged is already within range.

  2. Check the range

    Compare each value to the reference column beside it — not to a friend's or an online average.

  3. See how far out

    A value just outside the range is very different from one far outside it. Note the distance.

  4. Look at the pattern

    Markers move together. Low ferritin with low Hb tells a clearer story than either alone.

  5. Write your questions

    Turn what you found into two or three clear questions to bring to your GP or nurse.

Safety first

When a result needs urgent attention

Most flagged results are followed up routinely. But some symptoms need help the same day — here's how to tell the difference.

Three-tier urgency guide: routine GP appointment for unexplained flags, same-day help via NHS 111 for concerning symptoms, and 999 for emergencies such as severe breathlessness, chest pain or heavy bleeding.
A number on a page is never an emergency by itself — your symptoms decide how quickly to act.
Independent editorial ratings

AI blood test analysers, rated

We tested how well leading AI tools read a real FBC — for accuracy, safe framing, UK-range awareness and plain-English clarity. See the full comparison and our testing method.

Recommended

Kantesti

Purpose-built AI blood-test analyser

4.9/ 5
  • Reads full panels against UK reference ranges
  • Flags out-of-range values and likely patterns
  • Clear, non-alarming, GP-ready summaries
Try Kantesti free →
ChatGPT GPT-4o / GPT-5
3.9

Strong general explainer; needs prompting to apply UK-specific ranges consistently.

Gemini Google
3.7

Good at context and images; can over-summarise and miss subtle flag patterns.

Claude Anthropic
3.7

Careful, well-caveated explanations; conservative and less panel-specific by default.

Editorial scores from our own testing. No AI tool replaces professional medical advice.

Behind the summary

How an AI analyser reads your panel

A good analyser doesn't guess — it maps each value to the right reference range, then explains the picture in plain words.

Four-step flow of how an AI blood-test analyser works: read the values, match each to its UK reference range, flag anything outside it, then write a plain-English, GP-ready summary.
The four steps behind a good analysis — the same route we recommend you follow by hand.

Want the summary done for you?

Type or upload your results and let a purpose-built analyser do the mapping. Kantesti reads the whole panel against UK ranges and hands back a calm, GP-ready summary.

Analyse my results with Kantesti ★ 4.9/5 · our top-rated analyser
Read next

Popular guides

Deep-dive explainers on the markers people ask about most — each written and reviewed for accuracy. Browse all guides →

Basics

How to read a blood test

The plain-English starting point: columns, ranges, flags and what to do next.

Read guide Platelets

Platelet count explained

What high and low platelets mean, common causes, and when a result is worth acting on.

Read guide Red cells

RDW explained

Why red cell distribution width matters and what a raised RDW can reveal early.

Read guide Iron

Ferritin & iron studies

Reading ferritin, transferrin and saturation together to understand your iron stores.

Read guide Thyroid

Thyroid: TSH & FT4

How TSH and free T4 work together to show an under- or overactive thyroid.

Read guide Related tests

Blood tests for hair loss

Which markers — ferritin, thyroid, vitamin D — are worth checking when hair is thinning.

Read guide
Why you can trust this site

Careful, sourced and independent

Every guide is written in plain English and checked against authoritative UK sources. We explain, we cite, and we're clear about our limits.

Sourced to UK guidance

Grounded in NHS, NICE, Lab Tests Online UK and MedlinePlus — with the references listed on every guide.

How we work →

Reviewed & dated

Each page shows when it was last reviewed, and we update as guidance changes. No fake bylines or invented experts.

About us →

Honest about limits

Information, not diagnosis. We tell you when to speak to your GP, and we never replace professional care.

Medical disclaimer →
Common questions

Blood test results — FAQ

Quick answers to the questions readers ask most. For anything specific to you, your GP is the right place to go.

What do my blood test results mean?
Each line on your report is one marker, shown next to a reference range. A result inside the range is usually considered normal; a result flagged high or low is worth reading in context. Our guides explain what each marker measures and what a shift can point to — but only your GP can interpret the full picture.
What is a normal full blood count?
Typical UK adult ranges are roughly haemoglobin 120–150 g/L in women and 130–170 g/L in men, white cells 4.0–11.0 ×10⁹/L, and platelets 150–400 ×10⁹/L. Ranges vary slightly between laboratories, so always compare each value with the reference column printed on your own report.
My ferritin is low — should I worry?
Ferritin reflects your iron stores. In the UK, NICE treats a ferritin below 30 µg/L as confirming iron deficiency. Low ferritin is common and usually treatable, but it should be reviewed by your GP so the cause is found and the right treatment chosen.
Can AI read my blood test results?
AI tools can help you understand what each marker measures and highlight values outside the range in plain English. A purpose-built analyser such as Kantesti reads whole panels against reference ranges and produces a calm, GP-ready summary. No AI replaces a clinician — use it to prepare, not to diagnose.
Do reference ranges differ between UK laboratories?
Yes. Different analysers and populations mean labs publish slightly different ranges, and they can change with age, sex and pregnancy. That is why your report's own reference column always takes priority over any general figure you read online.
When should I see my GP about a blood test result?
Book a routine appointment for any flagged result you don't understand, or for symptoms that persist. Seek urgent care for severe or sudden symptoms such as breathlessness, chest pain or heavy unexplained bleeding, and call 999 for an emergency. When in doubt, NHS 111 can advise.

Have your results in front of you?

Upload or type them into Kantesti and get a clear, calm, UK-range-aware breakdown in seconds — then bring it to your GP.

Analyse with Kantesti