What leukemia is
Leukemia (blood cancer) is a malignant disease of the blood-forming system in which the bone marrow produces abnormal white blood cells. Acute leukemias develop quickly: immature cells (blasts) crowd out normal blood formation within weeks. Chronic leukemias progress over years and are often found by chance. By cell type, leukemias are divided into lymphoid and myeloid. The first test that raises suspicion is a complete blood count.
Which tests are done when leukemia is suspected
- a complete blood count (CBC) with a manual differential counted under the microscope;
- blood biochemistry;
- bone marrow aspiration;
- immunophenotyping, cytogenetic and molecular tests.
Complete blood count in leukemia: the values
White blood cells in leukemia
They may be very high (tens or hundreds of thousands per microlitre), normal or low, depending on the form of the disease. What matters is not so much the number of white cells as their composition.
Blasts and the leukemic gap
A healthy person has no blasts in peripheral blood. Their appearance is the main sign of acute leukemia. The leukemic gap is a picture in which blasts and mature cells are present while intermediate forms are almost absent.
Haemoglobin and red blood cells
They fall, causing anaemia. In acute leukemia haemoglobin may drop to 50–70 g/L and red cells to 1.5–2.5×1012/L. Before linking anaemia to leukemia, the doctor rules out iron and vitamin B12 deficiency.
Platelets in leukemia
Usually low in acute leukemia, often below 50×109/L, which shows as bruising and bleeding. In early chronic myeloid leukemia platelets may, on the contrary, be raised.
ESR in leukemia
Usually raised, sometimes to 40–60 mm/h or more, but this is a non-specific sign: ESR also rises with ordinary inflammation.
Basophils, eosinophils, reticulocytes
In acute leukemia basophils and eosinophils are often low or absent; in chronic myeloid leukemia they are raised. Reticulocytes fall because the bone marrow makes fewer red cells.
Example of a blood test in acute leukemia
Below is an illustrative example of how an adult's CBC may look in acute leukemia compared with normal values. Real figures differ from patient to patient, and reference ranges vary slightly between laboratories.
| Value | Normal | Example in acute leukemia |
| Haemoglobin | 120–150 g/L (women), 130–170 g/L (men) | 72 g/L |
| Red blood cells | 3.5–5.0×1012/L | 2.4×1012/L |
| Platelets | 180–320×109/L | 28×109/L |
| White blood cells | 4.0–9.0×109/L | 48×109/L (may also be below normal) |
| Blasts | 0% | 65% |
| ESR | up to 10–15 mm/h | 45 mm/h |
Blood test in different types of leukemia
- Acute lymphoblastic leukemia. Lymphoblasts predominate in the blood; anaemia and low platelets.
- Acute myeloid leukemia. Myeloblasts, the leukemic gap, marked anaemia and thrombocytopenia.
- Acute promyelocytic leukemia. White cells are often low, promyelocytes are present, and the risk of bleeding is high.
- Chronic myeloid leukemia. A high white cell count with cells at all stages of maturation and more basophils and eosinophils; blasts below 10%.
- Chronic lymphocytic leukemia. A persistent lymphocyte count above 5×109/L, while the person feels well for a long time.
Blood biochemistry in leukemia
There is no specific “leukemia tumour marker”. Biochemistry shows how the disease affects the body: LDH and uric acid are often raised, kidney and liver values may change, and beta-2 microglobulin rises in lymphoproliferative diseases.
Can leukemia be detected by a blood test
A blood test can raise suspicion of leukemia but cannot establish the diagnosis. Abnormal results are far more often caused by infections, inflammation, iron or B12 deficiency, medicines, pregnancy, smoking or physical strain. One “bad” result is therefore a reason to repeat the test with a manual differential and see a haematologist, not a verdict.
Symptoms of leukemia
- weakness, pallor, breathlessness on exertion;
- unexplained bruising, bleeding gums, nosebleeds;
- frequent and prolonged infections, fever;
- night sweats, weight loss;
- bone pain, enlarged lymph nodes, spleen and liver.
How the diagnosis is confirmed
- Bone marrow aspiration. Acute leukemia is diagnosed when blasts make up 20% or more of bone marrow cells.
- Immunophenotyping (flow cytometry). Shows whether the tumour consists of lymphoid or myeloid cells.
- Cytogenetic and molecular testing. Detects chromosome changes and mutations (Philadelphia chromosome, FLT3, NPM1 and others) that determine the prognosis and the choice of drugs.
- Lumbar puncture. Checks for tumour cells in the cerebrospinal fluid.
Treatment of acute leukemia
Acute leukemias, including acute lymphoblastic leukemia, are treated in specialised haematology units. Treatment consists of stages:
- Induction — intensive chemotherapy for 4–6 weeks aimed at remission.
- Consolidation — several courses that secure the result.
- Maintenance — lasts 2–3 years in lymphoblastic leukemia.
Chemotherapy is combined with targeted drugs and immunotherapy — monoclonal antibodies and CAR-T cells. Patients at high risk of relapse receive a bone marrow transplant. Supportive care is needed throughout: red cell and platelet transfusions, prevention and treatment of infections, anti-sickness medicines, and prevention of tumour lysis syndrome.
Prognosis
Outcomes depend on the type of leukemia, tumour genetics and age. In children with acute lymphoblastic leukemia five-year survival reaches about 90%. Results in adults are more modest, especially for acute myeloid leukemia in older patients. In chronic myeloid leukemia, targeted drugs have brought life expectancy close to normal.
Frequently asked questions
Which blood values point to leukemia?
Blasts in the blood, low haemoglobin, low platelets and a markedly abnormal white cell count, especially when they occur together.
Can leukemia occur with a normal white cell count?
Yes. In some forms of acute leukemia the white cell count is normal or low, so the differential, haemoglobin and platelets are what matter.
What should I do if blasts are found in my blood test?
See a haematologist urgently: a bone marrow aspiration is needed, and in acute leukemia treatment starts without delay.
Where is leukemia treated abroad?
In haematology-oncology centres in Germany, Israel, Turkey, Spain and South Korea.
Still have questions? Send a request — Clinics Direct medical coordinators will help you choose a clinic and haematologist and find out the cost of treatment, free of charge.
