Peripheral Blood Film (PBF)

Blood cell shape & anaemia type

In a peripheral blood film, a drop of your blood is spread thinly on a glass slide, stained and examined under a microscope. It shows the size, shape and appearance of red cells, white cells and platelets, which a machine count alone cannot fully describe. It helps your doctor work out the type and cause of anaemia and look for other blood disorders.

• When a CBC shows abnormal counts or unusual cell sizes
• To work out the type of anaemia, such as iron deficiency, B12 deficiency or thalassaemia trait
• Unexplained bruising, bleeding, fever or repeated infections
• To look for abnormal or immature white cells
• To check for signs of red cell breakdown (haemolysis)

Nothing special is needed and you can eat and drink normally. Continue your usual medicines unless your doctor advises otherwise, and tell your doctor about any recent blood transfusion, since it can change what is seen on the film.

Sample

Blood sample

How it works

The collector draws a small sample of blood from a vein in your arm during a home visit. At the laboratory, a drop of it is spread on a slide and examined under the microscope.

Report

Within 24 hours of collection.

The report describes what was seen rather than giving a single number. For example, small, pale red cells can suggest iron deficiency or thalassaemia trait, large red cells can point to low B12 or folate, and unusual white cells may need further tests. Some findings are minor and not significant. Your doctor will interpret the report with your blood count and symptoms and decide whether more tests are needed.

One test: Peripheral Blood Film (PBF), from one blood sample.