Microscopic examination of peripheral blood smear

Microscopic examination of a peripheral blood smear is a hematological investigation used to assess red and white blood cell morphology, perform a manual white blood cell differential, and identify any immature or morphologically abnormal cells.

The examination complements the automated complete blood count (CBC) and allows microscopic characterization of cellular abnormalities that cannot be adequately assessed by automated analysis.

Role of the examination

• confirmation and characterization of abnormalities detected in the complete blood count;
• identification of morphological abnormalities of red and white blood cells;
• identification of immature cells or blasts;
• detection of a left shift in the white blood cell differential;
• differentiation of reactive changes from those suggestive of a hematological disorder;
• assessment of anemia and morphological changes in red blood cells;
• identification of schistocytes when microangiopathy is suspected;
• guidance toward additional hematological investigations when pathological changes are identified.

Indications

• complete blood count abnormalities requiring microscopic confirmation;
• hematology analyzer flags indicating abnormal cells or suspicious cell populations;
• unexplained leukocytosis or leukopenia;
• persistent neutrophilia, neutropenia, lymphocytosis, or monocytosis;
• anemia of undetermined cause or significant abnormalities in red blood cell indices;
• suspected intravascular hemolysis or thrombotic microangiopathy;
• suspected leukemia, myelodysplastic syndrome, or another hematological disorder;
• suspected presence of immature cells or blasts;
• infections or inflammatory processes requiring morphological assessment of white blood cells;
• discrepancies between the automated complete blood count and the clinical presentation;
• monitoring of known hematological conditions, as recommended by the physician.

Procedure

Procedure steps

• collection of a venous / capillary blood sample;
• preparation and staining of the peripheral blood smear;
• microscopic examination of the smear;
• assessment of red and white blood cell morphology;
• performance of a manual white blood cell differential;
• description and, where appropriate, grading of morphological abnormalities;
• issuance of a morphological conclusion.

Interpretation of the result

The result should be interpreted in conjunction with:

• the automated complete blood count;
• red blood cell indices;
• absolute counts of white blood cell populations;
• clinical findings;
• the patient's medical history;
• other relevant hematological or biochemical investigations.

The identification of blasts, suspicious cell populations, or significant morphological abnormalities may require additional investigations, such as immunophenotyping, bone marrow examination, cytogenetic testing, or molecular testing, depending on the clinical context.