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Medical glossary

CBC: complete blood count

A complete blood count measures red blood cells, haemoglobin, white blood cells and platelets. It is the most frequent test in leukaemia.

Last updated: ~1 min read
An automated haematology analyser that counts blood cells in a laboratory
Figure 1.A CBC is run on an analyser

01Short answer

The report usually shows WBC (white cells) and their types (the differential), RBC and haemoglobin, haematocrit and platelets (PLT); sometimes blasts are noted. Each value is listed next to the laboratory's reference range. During treatment the counts fall and rise in expected ways; the trend matters more than a single number. Transfusions and treatment decisions are based on these results.

02Simple explanation

Three cell families.

The most frequent test.

Reference ranges.

The trend matters.

03Scientific explanation

NCI: a complete blood count measures the amounts of different cells in the blood.

The NCI Dictionary explains cancer terms in plain language; check the exact meaning for your situation with your doctor.

04What happens in the body?

Abbreviations

WBC, RBC, Hb, PLT and ANC.

A table
Figure 2.A table — CBC: complete blood count

Keeping track

Keep your results together with their dates.

The analyser
Figure 3.The analyser — CBC: complete blood count

Where you will see this word

In test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.

Ask your doctor

The general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

05From an unfamiliar word to a clear answer: four steps

Write it down, look it up, prepare a question, ask.

Write it down — From a result or a conversation.1Write it downFrom a result or a conversation.
Look it up — Learn the plain meaning.2Look it upLearn the plain meaning.
Prepare a question — What does this mean for me?3Prepare a questionWhat does this mean for me?
Ask — Your doctor gives the personal explanation.4AskYour doctor gives the personal explanation.
UnderstandingResults feel less frightening.
ConversationA shared language with your doctor.
SafetyNot drawing conclusions alone.

06Key points at a glance

TopicIn brief
AbbreviationsWBC, RBC, Hb, PLT and ANC.
Keeping trackKeep your results together with their dates.
Where you will see this wordIn test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.
Ask your doctorThe general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

07Key terms

WBC
White blood cells.
PLT
Platelets.
Term
A word with a precise medical meaning.
Reference range
The range a laboratory considers normal.

08Key points

  • Learn.
  • Ask your doctor.
  • Write it down.
  • Write the word down.
  • Ask what it means.

09Frequently asked questions

A number is marked in red: is it dangerous?

It is outside the normal range; your doctor will explain what it means.

How often is it done?

It depends on the treatment phase.

This word is in my results: should I worry?

The word itself does not mean a serious or mild condition; get the explanation from your doctor.

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. A number is marked in red: is it dangerous?

  2. How often is it done?

  3. This word is in my results: should I worry?

My questions

12Sources

  1. National Cancer Institute. NCI Dictionary of Cancer Terms: complete blood count
  2. MedlinePlus. Complete Blood Count (CBC)
  3. National Cancer Institute. NCI Dictionary of Cancer Terms
  4. National Cancer Institute. Leukemia
  5. National Cancer Institute. NCI Dictionary of Cancer Terms: cytogenetics
  6. National Cancer Institute. NCI Dictionary of Cancer Terms: thrombocytopenia
  7. National Cancer Institute. NCI Dictionary of Cancer Terms: leukopenia
  8. National Cancer Institute. NCI Dictionary of Cancer Terms: anemia
  9. National Cancer Institute. NCI Dictionary of Cancer Terms: red blood cell
  10. National Cancer Institute. NCI Dictionary of Cancer Terms: hemoglobin
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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