The short answer
Evaluation may include blood and marrow examination, immunophenotyping, chromosome and molecular testing, and CNS assessment. Each result should answer a specific diagnostic, risk, or treatment question.
Evaluation may include blood and marrow examination, immunophenotyping, chromosome and molecular testing, and CNS assessment.
Planning may depend on B- or T-cell type, Philadelphia chromosome or other findings, age, health, CNS involvement, and response.
A result can be diagnostic, prognostic, predictive, or useful for monitoring—and these are not identical roles.
Ask which results are confirmed and which remain pending.
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The full explanation.
Where the words on your report come from
Acute lymphoblastic leukemia starts in a lymphoid stem cell. Normally that cell becomes a lymphoblast. It then becomes one of three kinds of white blood cell. B lymphocytes make antibodies that help fight infection. T lymphocytes help B lymphocytes make those antibodies. Natural killer cells attack cancer cells and viruses.
In ALL, the body makes too many of these immature cells. They cannot fight infection well. They also crowd out the healthy blood cells the marrow should be making.
Most of your pathology report describes those immature cells. How many there are. What kind they are. And what has changed inside them.
The blood tests
A complete blood count (CBC) with differential checks a sample of blood. It measures the number of red blood cells and platelets. It measures the number and type of white blood cells. It measures the amount of hemoglobin, the protein that carries oxygen, in the red blood cells. And it measures the amount of hematocrit.
A peripheral blood smear also checks a sample of blood. It looks for blast cells, the number and kinds of white blood cells, the number of platelets, and changes in the shape of blood cells.
Blasts and the 5% line
Blasts are the immature leukemia cells. The percentage of blasts in your bone marrow is one of the most important numbers on the report. It is measured on a sample taken by bone marrow aspiration and biopsy. That means removing bone marrow, blood, and a small piece of bone through a hollow needle put into the hipbone.
For untreated ALL, all of the following are true: the CBC is abnormal, more than 5% of the cells in the bone marrow are blasts, and there are signs and symptoms of leukemia.
Your team uses the same number later to judge how treatment is working. In ALL in remission, the CBC is normal and 5% or fewer of the cells in the bone marrow are blasts.
Immunophenotyping: naming the cell type
Immunophenotyping uses antibodies to identify cancer cells. It does this by looking at the types of antigens, or markers, on the surface of the cells. This is the test that sorts the leukemia by cell type. Your report may name markers using letters and numbers.
NCI's patient summary does not spell out how B-cell and T-cell ALL differ in day-to-day treatment. If your report names a cell type, ask your team directly what that type means for the plan they are recommending.
Cytogenetics and the Philadelphia chromosome
Cytogenetic analysis examines the chromosomes of cells in a blood or bone marrow sample. It looks for changes, such as broken, missing, rearranged, or extra chromosomes.
The change named most often on an ALL report is the Philadelphia chromosome. This is an abnormal chromosome. It is made when pieces of chromosomes 9 and 22 break off and trade places. The ABL1 gene joins the BCR gene, forming a fusion gene called BCR::ABL1.
This finding is not only a label. Targeted therapy with imatinib is a treatment option for ALL. Dasatinib and nilotinib are also used. If your report mentions the Philadelphia chromosome, ask whether a targeted drug is part of your plan.
Checking the brain and spinal cord
A lumbar puncture collects a sample of cerebrospinal fluid, the fluid around the brain and spinal cord. The sample is checked under a microscope for signs that leukemia cells have spread there.
This matters because intrathecal chemotherapy, which is given into the spinal fluid, may be used to treat ALL that has spread, or may spread, to the brain and spinal cord. When it is given to prevent spread, it is called CNS prophylaxis.
What "risk" actually means here
NCI's patient summary does not sort adults into named risk groups. Instead it lists what prognosis and treatment options depend on. Your age. Whether the cancer has spread to the brain or spinal cord. Whether there are certain changes in the genes, including the Philadelphia chromosome. And whether the cancer has been treated before, or has come back.
If a clinician uses the phrase "risk group," it is fair to ask which of these factors they are weighing, and where each one appears on your report.
Results that may change the plan
Treatment for newly diagnosed adult ALL may include combination chemotherapy, targeted therapy with imatinib, CNS prophylaxis, chemotherapy with stem cell transplant, immunotherapy with blinatumomab or inotuzumab ozogamicin, and CAR T-cell therapy. Ask which of these your results open up, and which they rule out.
Questions worth asking
- What was my bone marrow blast percentage, and what will it be compared with next time?
- What cell type did immunophenotyping show, and how does that shape my treatment?
- Did cytogenetic testing find the Philadelphia chromosome or any other change?
- What did the lumbar puncture show, and am I getting CNS prophylaxis?
- Which results are still pending, and who will call me about them?
Words to know
Tap any term to see what it means.
Common questions
Why are so many tests needed?
Blood cancers can look similar while differing in cell type, biology, pace, and treatment response.
Does one gene result determine treatment?
Usually not by itself. The team interprets it with the full diagnosis, disease status, health, and treatment goals.
What is measurable residual disease?
It is sensitive testing for disease remaining after treatment; its meaning and use vary by blood cancer and test.
Can results be reviewed elsewhere?
You can ask whether specialist hematopathology review would increase confidence or change planning.
Questions to ask your doctor
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Sources last checked: 2026-07-22 what this meansLast updated: 2026-08-05Next planned review: 2027-07-22
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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