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Diagnosis and tests

How CLL is diagnosed

The related article (“CLL: symptoms, diagnosis and staging”) explains bone marrow biopsy. This topic covers what is special about diagnosing CLL (it is often made from a blood test alone) and which tests are done before treatment.

Last updated: ~1 min read
Small lymphocytes and smudge cells.
Figure 1.Small lymphocytes on a CLL smear.

01Short answer

Unlike many leukaemias, a CLL diagnosis usually does not need a bone marrow test. The blood count shows more small, mature lymphocytes; the diagnosis requires clonal B lymphocytes in the blood above a set level, lasting at least three months. The smear shows small lymphocytes and “smudge” cells. Flow cytometry of the blood is the key test: it shows clonal B cells that are positive for CD5, CD19 and CD23, with weak surface immunoglobulin. The doctor examines the lymph nodes, liver and spleen, which is the basis of the Rai or Binet stages. When treatment is needed, FISH (del(17p), del(11q), +12, del(13q)), TP53 mutation and IGHV mutation status are checked, because they affect the choice of treatment. The bone marrow is examined if there are unexplained cytopenias.

02Simple explanation

A blood test is often enough.

Flow cytometry: the key test.

Before treatment: genetics.

03Scientific explanation

IGHV status: mutated IGHV is usually linked to a calmer course and unmutated IGHV to a more active one; it does not change over time.

TP53/del(17p): reduces the response to some treatments, so it is rechecked before each line of therapy.

04What happens in the body?

Small lymphocytes

A CLL smear shows many small, mature lymphocytes.

Confirming the clone

Flow cytometry shows a single group of B cells in the blood.

A single group on a screen.
Figure 2.Flow cytometry confirms the clone.

Tests before treatment

Genetic tests help choose treatment.

A checklist card with gene icons.
Figure 3.Tests before treatment.

05Diagnosing CLL

Four steps.

Blood — Many lymphocytes.1BloodMany lymphocytes.
Flow — Clonal B cells.2FlowClonal B cells.
Stage — Nodes and spleen.3StageNodes and spleen.
Genetics — Before treatment.4GeneticsBefore treatment.

06Tests in diagnosing CLL

TestPurpose
Blood count, smearLymphocytosis, smudge cells
Blood flow cytometryCD5/CD19/CD23 clone
Physical examinationRai/Binet stage
FISH, TP53Risk before treatment
IGHV statusOutlook
Bone marrowOnly when needed

07Key terms

Clonal
Identical cells descended from one cell.
Smudge cell
A crushed lymphocyte on a smear.
Rai / Binet
Staging systems for CLL.
IGHV
An immunoglobulin gene whose status affects outlook.
MBL
Monoclonal B lymphocytosis, a condition that can come before CLL.

08Key points

  • CLL is often diagnosed from blood.
  • Flow cytometry is central.
  • The stage comes from examination.
  • Genetics is checked before treatment.
  • IGHV affects the outlook.
  • Not everyone needs a marrow test.

09Frequently asked questions

Why was no bone marrow taken from me?

In CLL the diagnosis is usually made from blood.

What is MBL?

A small number of clonal B cells in the blood; it can turn into CLL, but usually does not.

When are genetic tests done?

Usually when treatment is needed.

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. Why was no bone marrow taken from me?

  2. What is MBL?

  3. When are genetic tests done?

My questions

12Sources

  1. National Cancer Institute (NCI). CLL treatment (PDQ), patient version
  2. National Cancer Institute (NCI). Definition: flow cytometry
  3. National Cancer Institute (NCI). Definition: FISH
  4. MedlinePlus (U.S. National Library of Medicine). Fungal Culture Test
  5. MedlinePlus (U.S. National Library of Medicine). Procalcitonin Test
  6. NHS. Hepatitis B
  7. Cancer Research UK. Tests for acute lymphoblastic leukaemia (ALL)
  8. American Cancer Society. Testing Biopsy and Cytology Specimens for Cancer
  9. Cancer Research UK. Getting a second opinion
  10. Macmillan Cancer Support. Getting a second opinion
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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