Peripheral Blood Smears

Smear Preparations

 

 

RBC Morphologies

When RBCs vary in shape from one another it is called poikilocytosis. It can suggest...

Anisocytosis, or a variation in cell size from one another. This can be measured using the MCV or MCH.

 

Oval-shaped RBCs are called ellipotocytes, and show up sometimes in normal people and with anemia other times. Predominant elliptocytes are found in hereditary elliptocytosis.

 

Spherocytes are round cells with no central pallor, forming hemoglobin balls instead of doughnuts. They are seen in immune hemolytic states, as white blood cells (T cells, maybe?) attack RBCs and do x to them.

 

Target cells have more surface membrane than they should, forming bulged cells. They are seen in hemoglobinopathies (HbC, HbSC, HbE), in thalassemias, in iron deficiency, and liver disease.

 

Schistocytes are fragments of RBCs, caused by shearing of RBCs as they pass through microvessels full of coagulated fibrin. They are thus seen in hemolytic anemias, including DIC, TTP, HUS, and HELPP syndrome, as well as following severe burns.

 

Tear drop cells result from a stretching of RBCs, and are seen in myelofibrosis or other instances of deregulated growth in the bone marrow, such as metastasis.

 

Acanthocytes are spiky shaped cells, occurring in liver disease, abetalipoproteinemia, and asplenic people.

 

Echinocytes have less spikes and more multiple notches and can accompany uremia, pyruvate kinase deficiency, or could simply be an artifact from drying or old blood.

 

Sickle cells are behind sickly cell anemia, a problem with hemoglobin formation and subsequent cell shape and viability.

 

Pappenheimer Bodies are clumps of non-hemoglobin iron that are seen in states of cellular iron overload, which can occur in systemic iron overload, some anemias, and in asplenic people.

 

Howell-Jolly Bodies are remnants of chromitin from the defunct nucleus. These are normally removed by macrophages in the spleen (wow!) and thusly are seen in people with low functioning, or no, spleen.

 

Basophilic Stippling is caused by ribosomal precipitation during staining, often because of degrading RNA in young RBCs. Course stippling can be seen in lead and other metal poisonings, along with disorders of impaired Hb synthesis.

 

Autoaggutination of cells is seen in cold agglutinin disease(??)

 

Rouleau formations of cells stacked on top of each other is seen in plasma cell malignancy, as well as macroglobulinemia.

WBC Morphologies

 

flow cytometry may be useful

 

Increased

• reactive: infection, inflammation, neoplasm, drugs
• primary hematologic malignancy

decreased

• sequestration
• sepsis
• drugs
• marrow failure

 

 

Absolute neutrophil count: (ANC)

(PMN % + bands %) x WBC

 

activated lymphocytes: larger, may have granules and irregular shape: T or NK cells

 

atypical lymphocytes: large,basophilic, fine granules, nuclear change; associated with viral infection

 

abnormal lymphocytes: variable size, clefted nucleus, immature nucleus; suggestive of malignancy

 

typical CLL lymphocytes are mature; may be smear cells

 

Stains

details to come soon.

 

Azure B (blue) - binds anionic molecules (DNA, histamine, etc)

 

Eosin Y (pink) - binds cationic sites of proteins (hemoglobin, cationic eosinophil protein)

 

May-Grunwald-Giemsa

 

Wright-Giemsa