Getting the most out of your hemogram data (Proceedings)

Why do a CBC?

• Part of minimum database

• Evaluation of hematopoietic status

• Detection of inflammation/inflammation

• Detection of hematopoietic neoplasia

• Monitor therapy

• Detection/estimation of blood loss

Hemogram parameters one by one

• Total nucleated cell count

• Differential count including nucleated erythrocytes

• PCV/HCT

• RBC

• Hb

• MCV

• MCHC

• RDW

• RBC morphology (see below)

• WBC morphology

• Platelet count

Why review the smear?

• Corroborate automated counts

     o Especially important with instruments which do automated differentials

• Evaluate morphologic abnormalities

• Hemotropic parasites/microfilaria

• Platelet clumps

• Presence of abnormal cells

Approach to the blood smear

• Examine grossly

     o Appropriately made smear

     o Anemic?

     o Autoagglutination?

• 10x evaluation

• 50-100x evaluation (oil)

Approach at 10x

• Scan feathered edge

     o Platelet clumps**

     o Microfilaria

     o Abnormal cells- mast cells, neoplastic cells, megakaryocytes

• Estimate leukocyte count

• Find counting area

     o 3.5 10x fields from feathered edge

› Platelet clumps

› Appropriate counting area

› Estimation of leukocyte count

Oil immersion evaluation

• Differential leukocyte count

• Leukocyte morphology

• Evaluation of platelet numbers and morphology

• Evaluation of erythrocyte morphology and presence of polychromasia

Differential leukocyte count

• Lymphocyte v. nRBC

• Leukocyte morphologic abnormalities

• Lymphocytes with azurophilic granules

• Leukocyte morphologic abnormalities

• Erythrocyte morphologic abnormalities-Heinz bodies

• Erythrocyte morphologic abnormalities-acanthocytes

• Erythrocyte morphologic abnormalities-Howell-Jolly bodies

• Erythrocyte morphologic abnormalitieskeratocytes and fragments (schistocytes)

• Erythrocyte morphologic abnormalities-spherocytes

Common artifacts

Approach to blood film evaluation: A question based approach

• Perform a gross evaluation of the microscope slide

     o Is the blood film thick or thin?

     o Is there grossly evident agglutination?

     o Is the feathered edge normal or inverted?

     o Are the nucleated cells distributed evenly throughout the film?

     o Are there accumulated cells on the feathered edge?

• Evaluate the blood film at 100x (low power)

     o Are there platelet clumps, abnormal cells, or parasites on the feathered edge?

     o Is there a normal amount of rouleaux?

     o Are the erythrocytes agglutinated?

     o Is the leukocyte count decreased, normal, or increased?

     o Are there platelet clumps, abnormal cells, or parasites in the body of the film?

• Evaluate the blood film at 500x or 1000x (oil)

     o Are the platelet numbers adequate?

     o Is platelet size normal or increased?

     o Is platelet morphology normal or abnormal?

     o Is erythrocyte size decreased, normal, or increased?

     o Is erythrocyte morphology normal or abnormal?

          • Identify the erythrocyte abnormalities

          • Quantitate the incidence of abnormal morphologic features

     o Is the amount of polychromasia decreased, normal, or increased?

     o Are there any nucleated erythrocytes?

          • Identify and quantitate the nRBCs

          • Is the nRBC maturation sequence orderly or dysynchronous?

          • Do the numbers of nRBCs correlate with the degree of polychromasia?

     o Are there any hemoparasites?

     o Is the number of leukocytes decreased, normal, or increased?

     o Is leukocyte morphology normal or abnormal?

          • Perform a differential count

          • Are there toxic changes in neutrophils?

          • Are there reactive changes in lymphocytes?

          • Is there a left shift in any of the maturation sequence(s)?

          • Is the maturation sequence orderly or dysynchronous?