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Bindu PanapalliErythrocytic Morphology and Associated Diseases(Size and Shape)

NormocytesNormal erythrocytes

MacrocytesErythrocytes that have an MCV >100 fL.Seen in megaloblastic anemias, such B12/folate as deficiency.Occurs in anemia of liver disease.

Microcytesa. Are small RBCs less than 6 micrometers in diameter.b. Shows an MCV >80 fLc. Seen in iron deficiency anemias, thalassemias, hemolytic anemias, sideroblastic anemias, and chronic disorder anemias.

EchinocyctesCrenated RBCShow uniform round bumps or spikes on the RBC surface.Usually indicates artifacts of staining or increased platelets.No pathology is indicated.Caused by changes in cellular osmotic pressure.

Burr cellKeratocyctes.Irregular in size with spiny projections.Seen in renal insufficiency, liver disease, ulcers, and heparin therapy.Caused by cell membrane breakup due to cytoplasmic vacuoles.Can be confused with crenated erythrocyctes.

AcanthocytesAppear as small, densely stained RBCs with multiple irregularly spaced spikes or clublike projections.Associated MAHA(microangiopathic hemolytic anemia), alcoholic liver diseases, hereditary acanthocytosis, and abetalipoproteinemia.Caused by excessive cholesterol in the membrane.

Target CellsCodocytes or Mexican hat.Show a central area of hemoglobin surrounded by colorless ring and a peripheral ring of hemoglobin.Considered artifacts if appears in only one section of the smear.Seen in liver disease, Hb SS,SC, S thalassemia, thalassemia, iron deficiency, and postplenectomy

SpherocytesSlightly smaller (6.2-7.0 microliter) than normal RBC.Show no central pallor.Normal MCV, increased MCHC, and increased osmotic fragility.Seen in burns, hereditary spherocytosis, and extravascular hemolytic processes.Microspherocyctes are frequently seen in severe burn cases.Spherocyctes and microspherocytes result when the RBC surface area decrease due to a decrease in cell volume.

Teardrops

DacryocytesTennis racquet cellShow a tapered and round end. Slightly smaller than normocytes.Usually microcytic and/or hypochromicAbnormality is associated with myeloproliferative syndrome, pernicious anemias, ineffective erythropoiesis, thalassemia, and myelophthisic anemia.

Sickle CellsShapes vary but show thin, elongated pointed ends, and appear crescent shaped.Contains hemoglobin S.Seen in sickle cell anemia.Cell shape is caused by cell membrane alterations due to hemoglobin S.Decreased osmotic fragility.

Helmet Cells

KeratocytesInterior portion of the cell is hollow, resembling a helmet.These cell fragment are formed in the spleen and intravascular fibrin clots.Asscociated with microangiopathic hemolytic anemia.

Schistocytes

RBC fragment.RBC fragmentation results from passage through damaged or altered blood vessels.Variety of shapes : triangular, comma-shaped, helmet shaped.MicrocyticMay be found whenever blood vessel pathology is present.Seen in DIC, burns, renal transplant rejection and hemolytic processes.

StomatocytesCharacterized by an elongated or slitlike area of central pallor that resembles a mouth.Stomatocytes results from increased sodium and decreased potassium concentration within the cytoplasm of RBC.Seen in hereditary stomatocytosis, obstructive liver disease, alcoholism.

ElliptocytesOvalocytesCells have rod, cigar, or sausage shape.Caused by membrane integrity defect.Seen in hereditary elliptocytosis, iron deficiency anemias, megaloblastic anemia, thalassemia, and sickle cell anemia.

Nucleated RBCnRBCsMost are orthochromic normoblast but can appear in any erythrocytic stage of maturation.Indicate some type of bone marrow stimulation or increased erythropoiesis.Normally found in newborns.Seen in acute blood loss, leukemias, hypoxia,megaloblastic anemias, heart disease, and myelofibrosis.As few as one nRBC should be reported when seen on adult peripheral slide.