RBC Morphology

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Red cell morphology can be defined as the appearance of the erythrocytes on a Wright's stained smear.
Careful examination of the red cells for the purpose of identifying abnormalities is part of the differential procedure. This examination is important because it may provide valuable diagnostic information to the physician, as well as provide a quality control mechanism to verify red cell indices values as determined by automated or manual methods.

Test results
· RBC with a diameter >8µm  
· RBC thinner than normal (e.g. target cells) with normal MCV may appear as 'macrocytes'  
· Found in megaloblastic anemia (oval acrocytes); liver disorder, alcoholism, neonates, reticulocytosis  

· RBC diameter < 6.4µm  
· Found in iron deficiency anemia, thalassemia, hyperthyroidism  

· RBC of unequal size  
· Found in almost all red-cell diseases; non-specific; arked anisocytosis may be said to be normocytic  

· Oval and elliptical cells  
· Found in hereditary elliptocytosis, iron deficiency anemia, myelofibrosis  

Tear-drop poikilocytes
· Tear-drop appearance  
· Found in myelofibrosis, when bone marrow is replaced by non-haemopeitic tissue, and with extramedullary erythropoiesis  

Sickle cells (drepanocytes)
· Intermmediate sickling : rod-shaped, boat shaped and oat shaped  
· Found in sickle cell anemia  

Schistocytes (red cell fragments)
· The fragment are small and often appear spherical, triangular or irregular, deeply stained with irregular outline  
· Found in haemolytic anemia, burns, thalassemias, megaloblastic anemia, iron deficiency anaemia, elliptocytosis, DIC, thrombotic thrombocytopenic purpura, drug and toxins  

Crenated RBC = echinocytes
· Multiple short symmetric projection (10-30 spicules of equal length) due to disc-sphere transformation  
· Found as artifact (in stored blood, alkaline pH), in gross electrolyte imbalance  

Acanthocytes =spiny cells
· Irregular, unequal spicules (8-12 pointed projections) with a-beta-lipoproteinemia with markedly reduced lecithin content in cell membrane  
· Found in splenectomy, McLeod phenotype of Kell blood group  

Burr cells
· Irregular asymmetric projections, small cells or fragments  
· Found in uremia  

Spur cells
· RBC with long irregularly spaced projections  
· Found in liver disorder, normal infants, uremia, DIC, thrombotic thrombocytopenic purpura  

· Loss of bi-concavity (loss of surface membrane lipid, excessive sodium influx), smaller diameter, dense-staining  
· Found in hereditary spherocytosis or induced by chemicals or bacterial toxins or antibodies  

Target cells
· Increased surface area (due to increased cholesterol and lecithin) with same volume  
· Found in obstructive liver disorder, Hb C, D and E disorders; iron deficiency anemia  

· RBC with narrow slit-like area of central pallor  
· Found in hereditary stomatocytosis, liver disorder with alcohol abuse; in Rh-null genotype  

Nucleated red cells
· Erythrocytes with nuclei  
· Found in severe anemia(except aplastic), myelofibrosis, severe heart failure, hemolytic anemia.  

· Pale staining of RBC due to thin cell and low Hb conc  
· Found in iron deficiency, thalassemia, sideroblastic anemia  

· Reticulocytes with residual RNA have affinity for basic components of stain (blue)  
· Found in response to blood loss, haemolysis or haematinic therapy  

Dimorphism , anisochromasia
· Presence of two populations of RBC : hypochromic with normochromic, macrocytic/microcytic with normocytic  
· Found in sideroblastic anemia,megaloblasltic anaemia/iron deficiency anemia after treatment and after transfusion, Cooley's aneamia after transfusion  

Red cell inclusions
·Aggregate ribosomes RNA.  
·Howell-Jolly bodies:  
·DNA nuclear remnants, single deep purple of varying size; found in post-splenectomy, hyposplenism, megalobalstic anaemia, haemolytic anaemia.  
·Pappenheimer bodies:  
·Ferric compound complexed with protein; small dark blue bodies of uniform size, usually occur singly with absent splenic function.  
·Basophilic stippling = punctate basophilia  
·Aggregates of Ribrosomes, Multiple blue black inclusions evenly distributed; found in lead poisoning, thalassemias.  
·Heinz bodies  
·(by supravital staining, better with methyl violet, brilliant green is specific to Heinz bodies) Single round cell structure of denatured Hb at cell margin, as white unstained areas in MGG stain if haem is lost); found in post-splenectomy, due to oxidant stress of drugs and chemicals on unstable Hb (G6PD deficiency).  
·Hb H inclusion bodies  
·(supravital stain with new methylene blue, brilliant cresyl blue)  
·Precipitate tetramers of beta-globin chains;  
·Golf-ball appearance.  
·RBC with aggregates of ferritin or hemosiderin , demonstrated by Prussian blue.  
·Nucleated red cell containing ferritin molecules (up to 5 or more); found in iron deficiency and infection, "ringed" sideroblast is a characteristic feature of sideroblastic anaemia.  
·Cabot ring and chromatin dust  
·Remnants of mitotic spindle of nuclear membrane, altered microtubules;  
·Found in failure of erythropoiesis or in extramedullary blood formation.  
·Microorganism (Bartonella bacilliformis) and protozoa (Malaria parasite)  

All information on this page is intended for your general knowledge only and does not provide medical advice, diagnosis or treatment.