MLT GlobeHematology: RBC morphology & inclusions
89 Hematology MCQs on RBC morphology & inclusions with answers and explanations.
A normal mature red cell measures roughly how much across on a blood film?
Normal erythrocytes average about 7.2–7.5 µm in diameter, similar to the nucleus of a small lymphocyte, which is a handy size reference on films.
Which red cells show a blue granular network after staining with new methylene blue?
Supravital dyes precipitate residual ribosomal RNA in young red cells as a reticulum. Mature erythrocytes have no RNA; pronormoblasts are nucleated marrow cells.
A film shows red cells of many abnormal shapes, such as teardrops and fragments. What term describes this?
Poikilocytosis means variation in red cell shape. Anisocytosis refers to size variation; polychromasia to blue-grey young cells; hypochromia to pale cells.
A film shows red cells of very different sizes, reflected in a raised RDW. What is this called?
Anisocytosis means variation in red cell size, which the analyzer shows as a raised RDW. Poikilocytosis refers to variation in shape.
Marked rouleaux on a film and a very high ESR in an elderly patient suggest which condition?
Monoclonal immunoglobulin neutralizes red cell surface charge, causing stacking. Spherocytes, sickle cells and high hematocrit reduce rouleaux and lower the ESR.
Many schistocytes with thrombocytopenia most suggest:
Schistocytes are red cell fragments cut by fibrin strands in small vessels. With low platelets they point to a thrombotic microangiopathy, which in TTP is an emergency.
Howell-Jolly bodies are nuclear (DNA) remnants most commonly seen after:
The spleen normally removes these small round DNA fragments from red cells. After splenectomy or in functional asplenia (e.g. sickle cell disease) they stay in circulating cells.
Heinz bodies are best demonstrated by:
Heinz bodies are denatured, precipitated hemoglobin that is not visible on routine Romanowsky stains; supravital dyes such as crystal violet or brilliant cresyl blue show them. Prussian blue detects iron, not denatured hemoglobin.
A child with fat malabsorption and ataxia has red cells with a few irregular, unevenly spaced spiky projections and no central pallor. These cells are:
Acanthocytes have 2–20 irregular projections of different lengths and are typical of abetalipoproteinemia. Echinocytes have short, evenly spaced projections around the whole cell.
Polychromatic (bluish-grey) red cells on a Wright-stained smear correspond to which cells on a new methylene blue stain?
Polychromasia is due to residual ribosomal RNA taking up the basic dye; the same RNA forms the reticulum on supravital stain. Siderocytes contain iron granules, not diffuse RNA.
Rouleaux on a peripheral smear should be assessed only in the thin area where red cells just touch because:
In thick areas cells overlap and can look like coin stacks even in normal blood, giving a false impression of rouleaux. True rouleaux persist in the proper reading area.
Fine, dark blue-black granules are scattered over cells and the background of a Wright-stained smear. The most likely cause is:
Precipitate appears on and between cells and in the background, which true intracellular inclusions do not. Filtering the stain and proper washing prevent it.
When making a wedge blood film, which change produces a THICKER smear?
A steeper spreader angle gives a shorter, thicker film; a lower angle gives a longer, thinner one. A small drop or low hematocrit tends to produce thinner films.
In a normal red cell on a well-made smear, the central pallor occupies about:
Normal discocytes show central pallor of about one third of the diameter. Pallor larger than this indicates hypochromia, and a thin rim of hemoglobin is seen in severe hypochromia.
A patient with chronic kidney disease has many red cells with 10–30 short, evenly spaced projections on a fresh smear. These cells are called:
Echinocytes, also called burr cells, have short regular projections and are seen in uremia as well as in storage artefact. Acanthocytes have fewer, irregular projections.
Nucleated red cells in the peripheral blood of an adult usually indicate:
Nucleated red cells are normally found only in the marrow in adults; in the blood they suggest severe hemolysis, hypoxia, marrow infiltration or loss of splenic function. They are not produced by storage.
Marked anisocytosis on a blood smear is best reflected by which analyzer parameter?
RDW measures the spread of red cell volumes, which is what anisocytosis describes. MCH and MCHC describe hemoglobin content, and MPV refers to platelets.
Helmet cells and triangular red cells with sharp angles seen in a patient with DIC are classified as:
Helmet cells and triangular forms are types of red cell fragments (schistocytes), formed when cells are cut by fibrin strands or damaged surfaces. Acanthocytes are whole cells with irregular spicules.
A smear from an adult with homozygous sickle cell disease in steady state is most likely to show:
HbSS smears show irreversibly sickled cells and target cells, and Howell-Jolly bodies appear after autosplenectomy. Pencil cells suggest iron deficiency, and macro-ovalocytes suggest megaloblastic anemia.
Compared with a thin blood film, a thick film for malaria is mainly used to:
A thick film lyses red cells and concentrates a larger blood volume, so it is more sensitive for detecting parasites. Species identification and red cell changes need the thin film, where cells stay intact.