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Health condition · Clinically reviewed

Leukaemia, from first blood test to specialist treatment.

Four different diseases under one name - each with its own pace, genetics and treatment pathway. Understanding which type you're facing changes everything.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, BSH and ESMO guidance you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance including TKIs, BTK inhibitors, venetoclax and CAR-T therapy.

Key facts

Leukaemia at a glance.

The essentials, in plain English - what it is, the four main types, and how it's treated in the UK today.

  • What it is

    A group of cancers of the blood-forming tissue in bone marrow, where abnormal white cells crowd out normal blood cell production.

  • Main types

    Acute lymphoblastic (ALL), acute myeloid (AML), chronic lymphocytic (CLL) and chronic myeloid (CML) - each with a different age profile and pace.

  • Who it affects

    ALL is predominantly a childhood leukaemia; CLL is the most common adult leukaemia in the UK; AML and CML mainly affect adults.

  • How it is found

    Often incidental on a routine full blood count, or through fatigue, infections, bruising and bleeding.

  • Genetics

    The Philadelphia chromosome (BCR-ABL fusion) drives CML and a subset of ALL - the target for tyrosine kinase inhibitors.

  • Outlook

    Targeted drugs - TKIs, BTK inhibitors, venetoclax - and CAR-T therapy have transformed survival for several leukaemia types.

Why this guide matters

Four diseases, one name - and it matters which one.

"Leukaemia" covers conditions that behave very differently. The three points below shape everything else on this page.

  • Acute means urgent

    ALL and AML progress over days to weeks and need prompt, specialist-led treatment - this is not something to watch and wait on.

  • Chronic does not mean untreated

    CLL and CML are usually slower-moving, but "chronic" still means active specialist monitoring, and treatment when it is genuinely needed.

  • Genetics decide the drug

    The Philadelphia chromosome, FLT3, NPM1 and IDH1/2 status increasingly determine which targeted therapy gives the best outcome.

How the diagnosis is made

From a routine blood test to a confirmed diagnosis.

The steps a UK GP and specialist haematology team will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    FBC and blood film

    A full blood count and specialist review of blast cells on a blood film is usually the first clue.

  2. 02

    Assessing

    Symptom and history review

    Fatigue, infections, bruising, night sweats and weight loss are reviewed alongside the blood picture.

  3. 03

    Confirming

    Bone marrow aspirate and trephine

    A specialist-commissioned procedure that samples the marrow directly and confirms the diagnosis.

  4. 04

    Confirming

    Immunophenotyping

    Flow cytometry classifies the leukaemia subtype by the surface markers on the abnormal cells.

  5. 05

    Confirming

    Cytogenetics and molecular testing

    FISH and next-generation sequencing look for BCR-ABL, FLT3, NPM1 and IDH1/2 changes that guide treatment.

  6. 06

    Preparing

    Lumbar puncture (ALL)

    A specialist-led check for central nervous system involvement, relevant mainly in acute lymphoblastic leukaemia.

  7. 07

    Preparing

    MDT review

    A specialist haematology-oncology multidisciplinary team agrees the treatment plan at a designated UK centre.

Typical timeline: a first suspicious blood count to a full diagnosis in one to two weeks - faster for acute leukaemias.

Symptoms

What leukaemia actually looks like.

The classic triad of anaemia, infection and bleeding, plus the features that vary between the four main types. And the one that means it's time to get seen.

  • Fatigue and pallor

    From anaemia - a shortage of red cells as the marrow is crowded out by abnormal white cells.

  • Infections

    Frequent or severe infections reflect neutropenia - too few working white cells to fight them off.

  • Bruising and bleeding

    Thrombocytopenia - a low platelet count - shows as easy bruising, gum bleeding or nosebleeds.

  • Lymphadenopathy

    Swollen, usually painless lymph nodes in the neck, armpit or groin, more typical of CLL and ALL.

  • Hepatosplenomegaly

    An enlarged liver or spleen can cause abdominal fullness or discomfort under the left ribs.

  • Bone pain

    Marrow expansion can cause deep, aching bone pain, particularly in children with ALL.

  • B symptoms

    Fever, night sweats and unintentional weight loss can accompany any of the four main types.

  • Incidental finding - red flag

    Many leukaemias, especially CLL, are picked up on a routine blood test before any symptoms appear.

Treatment

How leukaemia is treated in the UK.

Chemotherapy for acute disease, targeted tablets for CML and CLL, and cellular therapy for relapsed cases - always agreed by a specialist multidisciplinary team.

  • ALL - induction chemotherapy

    Induction, consolidation and maintenance chemotherapy with CNS prophylaxis - the backbone of ALL treatment.

  • Tyrosine kinase inhibitors

    Imatinib, dasatinib and nilotinib target the Philadelphia chromosome in CML and Ph+ ALL - dramatic outcomes for many.

  • AML - induction (7+3)

    Standard induction chemotherapy followed by consolidation, with allogeneic transplant considered for high-risk disease.

  • Targeted AML therapy

    Midostaurin for FLT3-mutated disease, ivosidenib for IDH1 mutations, and venetoclax with azacitidine for patients unfit for intensive chemotherapy.

  • CLL - watch and wait

    Early, asymptomatic CLL is often monitored rather than treated - a considered, evidence-based strategy, not a delay in care.

  • BTK inhibitors and venetoclax

    Ibrutinib, acalabrutinib, zanubrutinib and venetoclax, often with obinutuzumab, have transformed CLL treatment.

  • Blinatumomab and CAR-T

    A bispecific antibody and CAR-T cell therapy (tisagenlecleucel) offer real options for relapsed or refractory ALL.

  • Allogeneic stem cell transplant

    Reserved for high-risk or relapsed disease across leukaemia types, decided at specialist MDT level.

Supportive care - blood and platelet transfusion, infection prophylaxis and careful symptom management - runs alongside every treatment pathway above, and stem cell transplant remains an option for high-risk or relapsed disease across all four types.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or haematology team knows your history and results and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Guidance on the diagnosis and management of leukaemias in adults and children.

  • British Society for Haematology (BSH). Diagnostic and treatment guidelines for ALL, AML, CLL and CML.

  • European Society for Medical Oncology (ESMO). Clinical practice guidelines for leukaemia.

  • Leukaemia Care and Blood Cancer UK. Patient information and support resources.

Red flags

When leukaemia needs urgent attention.

Most leukaemia care runs on a planned specialist timetable. These are the situations that don't wait for the next appointment.

  • Tumour lysis syndrome

    Rapid breakdown of leukaemia cells after starting treatment can disturb potassium, phosphate and kidney function - a medical emergency.

  • Neutropenic sepsis

    A fever during or after chemotherapy needs immediate hospital assessment - it can progress rapidly in a patient with no working white cells.

  • Hyperleukocytosis

    A very high white cell count can risk leukostasis - sludging in small blood vessels - and needs urgent specialist review.

  • CNS involvement

    New headache, visual change or cranial nerve signs in ALL should prompt urgent assessment for central nervous system disease.

  • Spontaneous bleeding

    Widespread bruising, gum bleeding or blood in urine or stool needs urgent platelet and blood count review.

  • Severe or unusual infection

    Recurrent, prolonged or atypical infections in someone with known or suspected leukaemia warrant prompt specialist input.

  • Graft-versus-host disease

    After an allogeneic stem cell transplant, skin, gut or liver symptoms need specialist transplant-team monitoring.

  • TKI resistance or relapse

    A rising BCR-ABL level on molecular monitoring in CML signals possible resistance and needs prompt specialist review.

  • Treatment-related toxicity

    TKIs and other targeted agents are monitored for cardiac, liver and other organ effects throughout treatment.

Living with it

A managed condition, with a clear specialist path.

Four things that make the biggest difference day to day - regular monitoring, trust in watch and wait where it applies, good support, and speaking up early about new symptoms.

A quiet reminder

Being monitored is being cared for.

For chronic leukaemias especially, regular review without immediate treatment is often the right, evidence-based approach - not a gap in your care.

  1. 01 Routine

    Regular blood monitoring

    FBC and, where relevant, molecular monitoring (such as BCR-ABL levels) track response and catch problems early.

  2. 02 Patience

    Watch and wait is a strategy

    For early CLL, active monitoring without treatment is evidence-based - not a sign that nothing is being done.

  3. 03 Support

    Charity and peer support

    Leukaemia Care and Blood Cancer UK offer information, helplines and peer support alongside your specialist team.

  4. 04 Escalate

    Report new symptoms promptly

    Fever, unusual bruising or breathlessness during treatment should always be reported the same day, not left until the next appointment.

Frequently asked

Everything we get asked about leukaemia.

Quick answers on types, causes, watch and wait, and newer treatments like CAR-T.

  • What is leukaemia?

    A group of cancers affecting the blood-forming tissue in bone marrow. Abnormal white blood cells multiply out of control and crowd out normal red cells, white cells and platelets, leading to anaemia, infection risk and bleeding.

  • What are the four main types?

    Acute lymphoblastic leukaemia (ALL), acute myeloid leukaemia (AML), chronic lymphocytic leukaemia (CLL) and chronic myeloid leukaemia (CML). "Acute" types progress quickly and need urgent treatment; "chronic" types usually progress more slowly.

  • What causes leukaemia?

    In most cases there is no single identifiable cause. Certain genetic changes - such as the Philadelphia chromosome (BCR-ABL) in CML - are well understood, but they are not usually inherited and are not caused by anything the patient did.

  • Is leukaemia always treated with chemotherapy?

    No. AML and ALL usually need induction chemotherapy, but CML is typically managed with tyrosine kinase inhibitor tablets, and early CLL may simply be monitored under watch and wait until treatment is actually needed.

  • What is watch and wait in CLL?

    A structured monitoring approach for early, asymptomatic chronic lymphocytic leukaemia. Studies show starting treatment early in this group does not improve outcomes, so regular blood tests and review are used until there is a clear indication to treat.

  • What is CAR-T therapy?

    A cellular therapy where a patient’s own T-cells are collected, genetically modified to recognise leukaemia cells, and returned by infusion. It is used for relapsed or refractory ALL and is delivered only at specialist-commissioned centres.

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