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Medical glossary

Introduction to the glossary: key terms

After a leukemia diagnosis, it can feel as if you have to learn a new language: blast, remission, neutropenia, MRD, port… These words come up again and again in test reports, conversations with doctors and on the hospital ward. This topic is an introduction to our glossary: it explains more than thirty of the most common terms in plain language, groups them by theme and helps you tell apart words that are often confused.

Last updated: ~4 min read
Different blood cells arranged like a constellation on a dark navy background, each glowing inside a soft halo of light and joined by fine lines.
Figure 1.Concept: each term names a small part of the world of blood.

01Short answer

Knowing medical terms makes conversations with your doctor easier, helps you read test results more calmly and ask the right questions. In this glossary the terms are grouped into four themes: blood and cells (blast, neutrophil, platelet), tests (complete blood count, bone marrow biopsy, FISH, karyotype), treatment (induction, consolidation, transfusion, port, transplant) and complications (neutropenia, febrile neutropenia, GVHD). Each definition is short and general; it does not explain your own results. If a word worries you, write it down and ask your hematology team.

02Simple explanation

Medical language can look frightening at first, but most of it describes simple ideas. For example, the ending “-penia” means a shortage: neutropenia is too few neutrophils, thrombocytopenia is too few platelets.

Some words mean something different in everyday speech. Remission is not the same as “cure”, and a blast is not an explosion but an immature young cell.

Abbreviations are especially confusing: CBC, ANC, MRD, HLA, GVHD. In the glossary we give the full form and plain meaning of each. If you see an unfamiliar abbreviation in a test report, make a note of it.

A definition only explains what a word means. The same number or result can mean different things for different people, so always ask your doctor what your own results mean.

03Scientific explanation

Where the definitions come from: we have simplified the definitions in this glossary from the US National Cancer Institute (NCI) Dictionary of Cancer Terms and the American Cancer Society’s patient materials. Each idea is explained in more detail in the matching topics on this site.

Three languages: in Azerbaijan, doctors often use Russian or English terms. That is why the glossary is prepared in three languages: by opening the same term in the AZ, RU and EN versions, you can find its equivalent.

Take care with abbreviations: some abbreviations look different in different languages, for example English AML is written “OML” in Cyrillic in Russian, and MRD becomes “MOB”. You may see either version in test reports; they mean the same thing.

04What happens in the body?

Blood and cells

Blast, neutrophil, lymphocyte, red blood cell, hemoglobin and platelet: these words describe what blood is made of. Knowing them makes a complete blood count much easier to read.

Tests and investigations

Bone marrow aspiration and biopsy, flow cytometry, karyotype, FISH and PCR are used to find out the type of leukemia and its genetic features. Their results form the basis of the treatment plan.

A translucent cross-section of bone on a dark navy background; blood cells flow out of the spongy marrow inside into a glowing blood vessel.
Figure 2.Many terms describe the journey from the bone marrow into the bloodstream.

Treatment

Induction, consolidation, maintenance, transfusion, PICC lines and ports, stem cell transplant, CAR-T: these words name the stages and tools of treatment.

Complications and safety

Neutropenia, febrile neutropenia, thrombocytopenia, sepsis and GVHD are especially important to know, because they relate to situations that may need urgent help.

How to use the glossary

Before an appointment, mark the words in your results that you do not know, look them up in the glossary and write down your questions. Asking your doctor to explain a word in plain language is completely normal.

05From an unfamiliar word to a clear answer

Useful steps when you meet a new term.

Write the word down — From a report or a conversation.1Write the word downFrom a report or a conversation.
Look it up — Learn its plain meaning.2Look it upLearn its plain meaning.
Prepare a question — What does this mean for me?3Prepare a questionWhat does this mean for me?
Ask your doctor — Only your doctor can explain it for you.4Ask your doctorOnly your doctor can explain it for you.
More understandingTest results feel less frightening.
Better conversationsYou share a language with your doctor.
Calmer decisionsYou understand what is happening.

06Words that are often confused

WordsDifferenceRemember
Remission / cureRemission means no trace of leukemia is found now; cure is spoken of after many years without relapseRemission is a big step, but not yet the end of the road
Neutropenia / leukopeniaNeutropenia is too few neutrophils; leukopenia is too few white blood cells of all kindsFor infection risk, neutrophils matter most
Aspiration / biopsyAspiration takes liquid marrow; biopsy takes a small core of bone with marrowOften done in the same procedure
Karyotype / FISHA karyotype looks at all the chromosomes; FISH looks for a specific changeBoth are cytogenetic tests
Induction / consolidationInduction aims to reach remission; consolidation aims to strengthen itBoth are stages of the treatment plan
PICC / portA PICC is placed through the arm and is visible outside; a port sits under the skinBoth need special care

* Definitions are simplified. Your hematology team will explain what each term means in your situation.

07Key terms

Blast
An immature young blood cell; their number rises in acute leukemia.
Neutrophil
A white blood cell that is the main defender against bacteria and fungi.
ANC
Absolute neutrophil count: the main measure used to judge infection risk.
Lymphocyte
A white blood cell involved in immune memory and making antibodies.
Hemoglobin
The protein in red blood cells that carries oxygen; when it falls, anemia develops.
Anemia
Too little hemoglobin or too few red blood cells; can cause tiredness and weakness.
Platelet
A tiny blood cell that helps blood to clot.
Thrombocytopenia
Too few platelets; raises the risk of bruising and bleeding.
Petechiae
Pinpoint red or purple spots on the skin; often linked to low platelets.
Neutropenia
Too few neutrophils; raises the risk of infection.
Febrile neutropenia
Fever during neutropenia; a situation that needs urgent medical care.
Sepsis
A dangerous condition in which an excessive response to infection damages organs.
CBC
Complete blood count: the basic test that counts blood cells.
Bone marrow aspiration
Taking a sample of the liquid part of the bone marrow with a needle.
Bone marrow biopsy
Taking a small piece of bone together with marrow with a needle.
Flow cytometry
A test that identifies cell types by the markers on their surface.
Karyotype
A test that looks at the number and structure of all the chromosomes in a cell.
FISH
A test that uses a fluorescent label to look for a specific gene or chromosome change.
PCR
A sensitive test that can find very small amounts of a genetic change.
Philadelphia chromosome
A changed chromosome carrying the BCR::ABL1 fusion gene; typical especially of CML.
Remission
No signs of leukemia on standard tests after treatment.
MRD
Measurable residual disease: a small number of leukemia cells found only by very sensitive tests.
Relapse
The return of leukemia after remission.
Induction
The first intensive treatment, aimed at reaching remission.
Consolidation
Treatment after remission to destroy hidden remaining cells.
Maintenance
Long-term, usually gentler treatment to keep remission.
Transfusion
Giving blood or blood components (red cells, platelets, plasma).
PICC line
A long-term catheter inserted through an arm vein up to a large vein near the heart.
Port
A small device under the skin connected to a vein; used for medicines and blood tests.
Stem cell transplant
Replacing a damaged blood-forming system with healthy stem cells.
HLA
Tissue markers used to judge donor compatibility for a transplant.
GVHD
Graft-versus-host disease: donor cells attacking the recipient’s tissues.
CAR-T
Treatment with the patient’s own T lymphocytes, changed in the laboratory.
Mutation
A change in DNA; some mutations define the type of leukemia and its treatment.

08Key points

  • Knowing the terms makes talking to your doctor easier.
  • The ending “-penia” means a shortage.
  • Remission is not yet cure.
  • Febrile neutropenia is an emergency.
  • Aspiration and biopsy are often done in one procedure.
  • Russian and English abbreviations mean the same thing.
  • Write down unfamiliar words and ask your doctor.
  • A definition does not explain your own result.

09Frequently asked questions

What does an asterisk or arrow in my test results mean?

Usually it means the value is above or below the laboratory’s normal range. But during treatment some values are expected to change. Ask your doctor what the result means for you.

What if my doctor did not explain a word?

It is completely normal to ask again. Questions such as “Could you explain that more simply?” or “How does this affect my treatment?” show your doctor how best to explain.

Why is the same test called by different names?

Laboratories and countries may use different names and abbreviations; for example the English CBC, the Russian “OAK” (in Cyrillic) and the Azerbaijani “UQA” are the same test. The glossary shows the equivalents.

Can I trust terms I find online?

Dictionaries from reliable organisations such as the NCI and the ACS are a good source. Explanations on forums and social media can be wrong or frightening. If in doubt, ask your doctor.

Will the glossary grow?

Yes. This is the introductory topic; separate topics on blood, test, genetics and treatment terms are being prepared.

How can I explain these terms to my child?

Use simple comparisons: neutrophils are “guard cells”, platelets are “patch-up cells”. A nurse or psychologist can also help you explain things in a way that suits your child’s age.

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. Could you explain the terms in my documents that I don't understand?

  2. What does this abbreviation in my result mean?

  3. Can you recommend a reliable source that explains medical terms simply?

  4. Could we go through my discharge summary together?

My questions

12Sources

  1. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms
  2. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: blast
  3. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: remission
  4. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: minimal residual disease
  5. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: induction therapy
  6. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: consolidation therapy
  7. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: neutropenia
  8. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: febrile neutropenia
  9. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: platelet
  10. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: transfusion
  11. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: bone marrow biopsy
  12. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: fluorescence in situ hybridization
  13. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: karyotype
  14. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: peripherally inserted central catheter
  15. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: port
  16. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: stem cell transplant
  17. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: graft-versus-host disease
  18. American Cancer Society. Low Blood Counts
  19. American Cancer Society. Neutropenia (Low White Blood Cell Counts)
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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