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Diagnosis and tests

How AML is diagnosed

The related article (“AML: symptoms and diagnosis”) explains platelets. This topic shows, step by step, the whole path to an AML diagnosis, from the blood count to the genetic risk group.

Last updated: ~1 min read
Five glowing stones.
Figure 1.The AML diagnostic path.

01Short answer

An AML diagnosis usually begins with changes on a blood count: anaemia, low platelets, a high or low white count, and blasts in the blood. Next comes a bone marrow aspiration and biopsy. Microscopy shows the percentage of blasts: usually 20% or more confirms AML, but with certain genetic changes the diagnosis is made at a lower percentage. Flow cytometry confirms that the cells are myeloid. Cytogenetics and FISH find chromosome changes, and molecular tests (NPM1, FLT3, CEBPA, TP53, IDH1/2 and others) find mutations. Together these define the AML subtype and risk group (favourable, intermediate or adverse). In addition, clotting tests (to rule out APL), kidney and liver tests, a heart check and sometimes a lumbar puncture are done.

02Simple explanation

Blood → marrow → genetics.

20% blasts: the usual threshold.

Risk group: based on genetics.

03Scientific explanation

Genetic risk: the ELN classification combines cytogenetic and molecular results into favourable, intermediate and adverse groups; this affects the decision about transplant.

Urgent tests: the FLT3 result, and sometimes NPM1, is needed quickly because it may affect whether targeted drugs are added.

04What happens in the body?

The diagnostic path

Each test is a step; together they make the full diagnosis.

Blasts in the marrow

The percentage of blasts is counted in the marrow sample.

A smear full of blasts.
Figure 2.Many blasts in the marrow.

Genes and risk

Genetic findings define the risk group.

Gene markers leading to boxes.
Figure 3.Genes and risk groups.

05Diagnosing AML

Four steps.

Blood — First suspicion.1BloodFirst suspicion.
Marrow — Aspiration and biopsy.2MarrowAspiration and biopsy.
Type — Flow cytometry.3TypeFlow cytometry.
Genes — Risk group.4GenesRisk group.

06Tests in diagnosing AML

TestPurpose
Blood count, smearSuspicion, blasts
Marrow aspiration/biopsyBlast percentage
Flow cytometryMyeloid lineage
Cytogenetics, FISHChromosome changes
Molecular panelNPM1, FLT3, TP53 and others
Clotting testsRule out APL/DIC

07Key terms

AML
Acute myeloid leukaemia.
ELN
The European LeukemiaNet risk classification.
FLT3
A gene that affects targeted treatment.
NPM1
A gene often mutated in AML.
Risk group
A group based on outlook.

08Key points

  • AML diagnosis starts with the blood.
  • The marrow test is central.
  • 20% blasts is the usual threshold.
  • Flow cytometry confirms the lineage.
  • Genetics gives the risk group.
  • Ruling out APL is urgent.

09Frequently asked questions

Will I wait for all the results?

Sometimes treatment starts quickly and the plan is refined as results come in.

What does the risk group mean?

It is used to estimate the expected course and how intensive treatment should be.

Does my family need tests?

If a transplant is planned, brothers and sisters may be tested for a match.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Will I wait for all the results?

  2. What does the risk group mean?

  3. Does my family need tests?

My questions

12Sources

  1. National Cancer Institute (NCI). Adult AML treatment (PDQ), patient version
  2. MedlinePlus. Bone marrow tests
  3. MedlinePlus. Bone marrow aspiration
  4. National Cancer Institute (NCI). Tumor markers in common use
  5. MedlinePlus Genetics. BCR gene
  6. American Cancer Society. Imaging (Radiology) Tests for Cancer
  7. National Cancer Institute (NCI). Computed Tomography (CT) Scans and Cancer
  8. RadiologyInfo.org (RSNA and ACR). Radiation Dose in X-Ray and CT Exams
  9. MedlinePlus (U.S. National Library of Medicine). CT Scans
  10. MedlinePlus (U.S. National Library of Medicine). MRI Scans
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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