Blood and lab tests
What Is a Blood Smear and What Do the Comments Mean?
Blood smear · say it: BLUD smeerAlso written: peripheral blood smear, blood film, peripheral smear, blood film examination
Short answer
A blood smear is a thin layer of your blood spread on a glass slide so a trained person can look at the cells under a microscope.
What it means
For a blood smear, a drop of blood is spread very thinly across a glass slide, stained with dyes and examined under a microscope. A lab scientist or a doctor who specialises in blood looks at the size, shape and colour of red cells, counts the different kinds of white cells and checks the platelets.
A machine count, like a full blood count, gives numbers. A smear shows what the cells actually look like. It is often added when the machine flags something unusual, or when a doctor wants a closer look at anemia, an infection or a low or high cell count. The report is usually a few short comments rather than a single number.
A smear is not the same as a full blood count, although the two are often reported together. It is also different from a bone marrow test, which looks at where blood cells are made rather than the cells already circulating in the blood.
Where you may see it
- A 'Film comment' or 'Blood film' box under a full blood count result
- Hematology reports with words like anisocytosis, poikilocytosis or target cells
- Lab results that say 'smear reviewed by pathologist'
- Malaria test reports, where a thick and thin smear is examined for parasites
📄 How it looks on a report
Blood film: Red cells show mild anisocytosis with occasional target cells. White cells and platelets appear normal in number and form. No blasts seen.
🙅 What it does not mean
- A smear being ordered does not mean the lab suspects something serious. Labs often review a slide automatically when a machine count is outside its usual pattern.
- Unfamiliar words on a smear report are descriptions of what the cells look like, not diagnoses. Your doctor reads them together with your symptoms and other results.
- A smear that looks unremarkable does not rule out every blood problem, because some conditions need other tests to find them.
🗒️ Questions to ask your doctor
🧾 Reports where you will see “Blood smear”
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🔗 Read more from trusted sources
- “Blood smear” on MedlinePlus ↗
US National Library of Medicine
- MedlinePlus lab test guides ↗
US National Library of Medicine
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