Diagnosis of leukaemia is a critical process that involves a combination of clinical evaluation, laboratory testing, and imaging techniques to confirm the presence and type of this complex blood cancer.
Since the diagnosis of leukaemia affects treatment choices and long-term outcomes, early and accurate testing matters. Many patients first visit a doctor with vague symptoms like fatigue, fever, or frequent bruising. These signs push doctors to do further tests. A clear process helps ensure the disease is found and classified correctly.
Initial Clinical Assessment
The process begins with a full medical history and physical check-up. Doctors ask about symptoms, past illnesses, and any family history of cancer. Symptoms such as repeated infections, bleeding gums, night sweats, or swollen lymph nodes may raise red flags. During the physical exam, the doctor may notice signs like pale skin or an enlarged liver or spleen.
Although these symptoms may appear in other conditions, they help guide next steps. If leukaemia is suspected, the general practitioner sends the patient to a blood specialist—a haematologist. This doctor then orders tests to confirm the presence of abnormal cells and rule out other illnesses.
Blood Tests and Cell Examination
One of the first tools used in the diagnosis of leukaemia is the full blood count (FBC). This test measures the levels of red cells, white cells, and platelets. A result showing low red cells, unusual white cell counts, or fewer platelets may point to leukaemia.
Along with the FBC, doctors use a blood smear. This test checks the shape and stage of cells under a microscope. In acute leukaemia, early signs include abnormal white cells called blasts. In chronic leukaemia, more mature but still abnormal cells might appear. If these are present, doctors move on to more detailed testing.
Bone Marrow Testing in Diagnosis of Leukaemia
A firm diagnosis often comes from a bone marrow biopsy and aspiration. In this test, a small sample of bone marrow is taken—usually from the hip bone—using a needle under local anaesthetic. Doctors check this sample for the number and type of blood cells, especially the number of blast cells.
If the blast count is 20% or more, acute leukaemia is usually confirmed. The sample also goes through further testing. Two key methods—cytogenetic analysis and flow cytometry—help spot gene changes and confirm the type of leukaemia. This information is vital for choosing the right treatment and understanding how the disease might progress.
Genetic and Molecular Testing
To better understand the diagnosis of leukaemia, doctors also use tests that study chromosomes and genes. Cytogenetic tests like karyotyping look at changes in the structure of chromosomes. These may show key clues—like the Philadelphia chromosome, which appears in CML, or other genetic shifts seen in ALL and AML.
Doctors also use PCR and FISH tests. These spot very small changes in DNA that help confirm leukaemia and plan treatment. Some of these changes also guide the use of special drugs that target the cancer more precisely.
Flow Cytometry and Immunophenotyping
Another key test is flow cytometry, used for immunophenotyping. This method tags cells with fluorescent dyes and helps tell one type of leukaemia from another. For example, it can show whether the cancer involves B-cells or T-cells.
Knowing this helps doctors design a plan that fits the exact disease type. This test also helps detect any leftover cancer after treatment—called minimal residual disease—which is important for tracking recovery and adjusting care.
Lumbar Puncture and Imaging
Sometimes, leukaemia spreads to the brain and spinal cord. This is more common in ALL. If doctors think this might be happening, they perform a lumbar puncture. This test collects fluid from the spine to check for cancer cells. It’s done if patients have symptoms like headaches, vision changes, or seizures.
Imaging tools like X-rays, CT scans, or ultrasound may also help. They show if organs like the spleen or lymph nodes are larger than normal. These tests do not confirm the diagnosis but offer helpful information about how far the disease has spread.
Staging and Risk Stratification
Once the diagnosis is confirmed, doctors check how advanced the disease is. This step, called staging, looks at how much cancer is in the body and how fast it may grow. Doctors also consider risk factors like age, white cell count, and gene changes.
For example, in ALL, patients are placed into standard-risk or high-risk groups. This helps guide how strong the treatment should be. In CLL, doctors use systems like Rai or Binet staging to measure disease level and decide when to start therapy. Grouping patients by risk makes treatments more personal and effective.
Paediatric and Adult Diagnosis: Key Differences
Children go through the same basic tests, but doctors take extra care during diagnosis. Kids may react more strongly to illness or feel more fear. Since children often get ALL, doctors move quickly to start treatment. Special paediatric teams use equipment and steps suited to younger bodies.
Emotional support also plays a major role. Psychologists and counsellors often join the care team early to help families cope. They guide parents and children through what can be a confusing and scary process.
Ongoing Tests and Monitoring
After the first diagnosis of leukaemia, the journey continues with regular testing. Doctors keep track of blood counts, bone marrow changes, and gene activity to see how well treatment is working. These follow-up tests show whether the patient is in remission or if changes to treatment are needed.
By keeping a close watch, doctors can spot a relapse early and act fast. For patients receiving bone marrow transplants or targeted drugs, ongoing testing helps doctors manage long-term results and avoid future problems.
Final Thoughts on Diagnosis of Leukaemia
The diagnosis of leukaemia is not a simple task. It involves many tests and expert review to make sure every detail is clear. Finding the exact type of leukaemia early makes it possible to start the right treatment and improve results. Thanks to new tools and advanced lab work, doctors can now find even tiny disease markers. This helps them plan better treatment and offer more hope to patients and their families.
