A peripheral blood smear (blood film) is a thin layer of blood spread on a glass slide, stained and examined under a microscope to evaluate the shape, size, number and appearance of red and white blood cells and platelets. It helps diagnose anemia types, infections, blood cancers, platelet disorders and parasites (e.g., malaria), and is interpreted by laboratory staff or a pathologist alongside automated counts.

A positive peripheral blood smear means microscopic examination found abnormal blood-cell features. This may show altered cell shape or size, immature cells (blasts), signs of hemolysis, platelet abnormalities, or parasites (e.g., malaria). Such findings suggest conditions like anemia, infection, or blood cancers and must be interpreted alongside the complete blood count and clinical history; further specialist testing is usually needed.

The peripheral blood film (PBF) test examines a stained blood smear under a microscope to assess red and white blood cell size, shape and maturity, and platelet appearance. It helps diagnose and classify anaemias, infections (including malaria), blood cancers (leukaemia), hemolysis, platelet disorders and blood parasite infestations, and to investigate abnormal complete blood counts or unexplained symptoms such as fatigue or bleeding.

Smear (smudge or basket) cells are ruptured white blood cells seen on peripheral blood films. They result from fragile leukocytes or mechanical damage during slide preparation and handling — e.g., prolonged EDTA exposure, delayed processing, rough smearing, cold exposure. They are common in chronic lymphocytic leukemia, where lymphocytes are intrinsically fragile, and can also appear with severe infections, toxins, burns, or after chemotherapy.

Costs vary by country and lab. In India private labs typically charge about ₹150–₹600. In the United States private lab fees commonly range roughly $30–$150, though hospital billing can be higher. In places with public health systems it’s often free at point of care. Final cost depends on location, whether it’s bundled with a CBC, and specialist review.

A peripheral blood film can often detect signs suggestive of leukemia by showing abnormal white cells, circulating blasts, marked leukocytosis or cytopenias and platelet or red cell changes. It is a useful initial test but not definitive: diagnosis requires bone marrow examination with immunophenotyping (flow cytometry), cytogenetic and molecular tests. Suspected cases need urgent specialist referral for confirmation and treatment.