← Back
Treatment and the treatment process

Laboratory monitoring

Blood tests are done often throughout leukemia treatment. They show whether treatment is safe and working.

Last updated: ~2 min read
On a dark navy background, red cells, white cells and platelets gathered into three glowing clusters of red, teal and gold.
Figure 1.A full blood count measures the main cells.

01Short answer

Laboratory monitoring is a core part of leukemia treatment. The most common test is the full blood count (FBC/CBC): haemoglobin, white cells and their types (especially neutrophils), platelets and sometimes blast cells. A chemistry panel shows the kidneys (creatinine, urea), electrolytes, liver (ALT, AST, bilirubin), uric acid and albumin. Clotting tests (PT/INR, fibrinogen) matter in some leukemias, such as APL, and during asparaginase treatment. Blood levels are measured for some medicines, and cultures and virus tests are done if infection is suspected. Response of the disease itself is shown by bone marrow tests and measurable residual disease (MRD) tests. How often tests are done depends on the phase — daily during intensive treatment, less often when stable.

02Simple explanation

Blood tells a story. Tests show what is happening inside.

Cells. Red cells, white cells and platelets are counted.

Organs. Kidney and liver results are checked.

Trends. The direction of change matters more than one number.

03Scientific explanation

FBC and differential: the absolute neutrophil count (ANC) is the key measure of infection risk; platelets help judge bleeding risk and the need for transfusion, and haemoglobin the need for red cells. Blasts on a blood film can indicate disease activity.

Chemistry and clotting: tumour lysis markers (potassium, phosphate, calcium, uric acid, LDH), kidney and liver function, and fibrinogen and D-dimer for DIC. Asparaginase can lower fibrinogen and antithrombin.

Disease monitoring: bone marrow morphology and MRD by flow cytometry or molecular methods; in CML, measuring the BCR::ABL1 transcript by PCR. These tests shape treatment decisions.

04What happens in the body?

Blood cells

The bone marrow makes red cells (oxygen), white cells (defence) and platelets (clotting). Their numbers fall and rise during treatment.

In the laboratory

Samples are measured by automated analysers, and a specialist looks at a film under the microscope when needed. Results are usually ready within hours.

Capped sample tubes move along a ribbon of teal light into a modern laboratory analyser.
Figure 2.Samples are measured automatically in the laboratory.

Look at the trend

The direction of change over time says more than a single result. Your doctor interprets results together with how you are overall.

On a dark background, a smooth gold curve with glowing points rises gently.
Figure 3.The trend in results says more than one number.

05The test cycle

A simplified outline.

Sample — Blood or urine.1SampleBlood or urine.
Testing — In the laboratory.2TestingIn the laboratory.
Recording — Results collected.3RecordingResults collected.
Discussion — With your doctor.4DiscussionWith your doctor.
Safe treatmentRisks seen in time.
EffectivenessDisease response tracked.
The right frequencyBy treatment phase.

06Main tests and what they mean

TestWhat it showsWhy it matters
HaemoglobinRed bloodTiredness, transfusion need
NeutrophilsDefence against infectionInfection risk
PlateletsClottingBleeding risk
Creatinine, electrolytesKidneys, salt balanceMedicine doses, rhythm
ALT, AST, bilirubinLiverMedicine tolerance
PT/INR, fibrinogenClotting systemBleeding and clot risk
MRD, BCR::ABL1Residual diseaseTreatment decisions

* Normal ranges vary between laboratories; your doctor explains your results.

07Key terms

FBC/CBC
Full (complete) blood count.
ANC
Absolute neutrophil count.
Differential
The share of each type of white cell.
Chemistry panel
Blood tests that show organ function.
MRD
Measurable residual disease — a very small number of remaining leukemia cells.
Nadir
The lowest point of blood counts after chemotherapy.

08Key points

  • Tests show whether treatment is safe.
  • The trend matters more than one number.
  • With low neutrophils, fever is an emergency.
  • Keeping your own record of results helps.
  • Normal ranges depend on the laboratory.
  • Discuss every result with your doctor.

09Frequently asked questions

Why is blood taken so often?

In intensive treatment counts and salts change quickly; seeing this in time is vital for safety.

Can I look up my results online?

You can read general information, but "normal" means something different in leukemia — leave interpretation to your doctor.

Can blood be taken from my central line?

Yes, often; it reduces needle sticks into veins.

What is the nadir?

The time after chemotherapy when blood counts are lowest; infection risk is highest then.

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 is blood taken so often?

  2. Can I look up my results online?

  3. Can blood be taken from my central line?

  4. What is the nadir?

My questions

12Sources

  1. MedlinePlus. Complete Blood Count (CBC)
  2. MedlinePlus. Comprehensive Metabolic Panel (CMP)
  3. Cancer Research UK. Blood test
  4. National Cancer Institute (NCI). Infection and Neutropenia during Cancer Treatment
  5. Journal of Clinical Oncology, 2020. Antiemetics: ASCO Guideline Update
  6. New England Journal of Medicine, 2011. The tumor lysis syndrome
  7. National Cancer Institute (NCI). Nerve Problems (Peripheral Neuropathy) and Cancer Treatment
  8. National Cancer Institute (NCI). Memory or Concentration Problems and Cancer Treatment
  9. National Cancer Institute (NCI). Late Effects of Cancer Treatment
  10. ICUsteps. Guide to intensive care: effects on your body
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
Last updated: ← Back to the list

Open the interactive site →