MLT GlobeHematology: RBC morphology & inclusions – page 2
89 Hematology MCQs on RBC morphology & inclusions with answers and explanations.
Which condition most typically produces many spherocytes on the peripheral smear?
In warm AIHA, macrophages remove part of the IgG-coated membrane, producing spherocytes. Liver disease gives target cells, iron deficiency pencil cells, and lead basophilic stippling.
Nucleated red cells in the peripheral blood are a normal finding in:
Healthy term newborns commonly have a few nucleated RBCs, which disappear within about the first week. In adults they usually point to marrow stress or infiltration.
Heinz bodies are composed of:
Oxidized hemoglobin denatures and precipitates, sticking to the inner membrane as Heinz bodies. RNA forms stippling, iron granules are Pappenheimer bodies and DNA forms Howell-Jolly bodies.
The biconcave shape of a normal red cell mainly allows it to:
A biconcave disc has more surface area than a sphere of the same volume, so it can fold and pass through narrow capillaries and splenic slits. Spherocytes lose this reserve and are trapped.
The term 'poikilocytosis' describes:
Poikilocytosis means abnormal shapes. Anisocytosis refers to size, polychromasia to bluish color, and rouleaux to stacking.
A drepanocyte is another name for a:
Drepanocyte comes from the Greek for sickle. A target cell is a codocyte, a teardrop cell is a dacrocyte and a burr cell is an echinocyte.
On a Wright-stained smear, spherocytes are recognized as red cells that are:
Spherocytes are round, stain densely and have no central pallor because they have lost their biconcave shape.
A normal biconcave red cell is described by which term?
A discocyte is the normal biconcave disc. Codocytes are target cells, dacrocytes are teardrop cells and echinocytes are burr cells.
Enlarged infected red cells with fine pink-red stippling (Schüffner dots) on a Giemsa-stained thin film suggest infection with:
Schüffner dots in enlarged red cells are typical of P. vivax (P. ovale shows similar dots). P. falciparum shows Maurer clefts, and P. malariae infects normal-sized cells without Schüffner dots.
A red cell containing iron granules (Pappenheimer bodies) that stain with Prussian blue is called a:
A siderocyte is a red cell that contains iron-positive granules. Spherocytes, stomatocytes and schistocytes are shape changes.
A red cell with a central dark spot of hemoglobin, surrounded by a pale ring and an outer rim of hemoglobin, is a:
This bull's-eye appearance defines the target cell (codocyte), which is seen in liver disease, hemoglobinopathies and thalassemia.
On a blood smear, a normal red cell is roughly the same size as:
A normal red cell (about 7–8 µm) is similar in size to the nucleus of a small lymphocyte, a handy check when judging micro- or macrocytosis.
Red cells are described as microcytic when the adult MCV is below about:
The adult MCV reference range is roughly 80–100 fL. Below 80 fL is microcytic and above 100 fL is macrocytic.
Supravital staining of a G6PD-deficient patient's blood after an oxidant drug shows round inclusions at the membrane. What are they?
Oxidized hemoglobin precipitates as Heinz bodies, seen with supravital stains. Howell–Jolly bodies are DNA remnants; stippling is aggregated ribosomes.
More than 25% of a patient's red cells are oval to elongated, with a family history of the same. Which finding is this?
Elliptocytes in large numbers, often from a spectrin or protein 4.1 defect, indicate hereditary elliptocytosis. Stomatocytes have slit-like central pallor; echinocytes have regular spicules.
Target cells (codocytes) are typical of all of the following EXCEPT:
Target cells have extra membrane relative to their volume: seen in liver disease, HbC and thalassemia. Spherocytes have the opposite problem, too little membrane.
Small, irregular clusters of granules near the edge of some red cells on a Wright-stained smear are confirmed as Pappenheimer bodies when they:
Pappenheimer bodies contain iron and stain blue with Prussian blue; red cells with these iron granules are called siderocytes. Feulgen positivity indicates DNA, which is the feature of Howell-Jolly bodies.
Thin, red-violet ring or figure-of-eight structures in red cells of a patient with megaloblastic anemia are:
Cabot rings are thought to be remnants of the mitotic spindle and occur in severe megaloblastic anemia and lead poisoning. Howell-Jolly bodies are round DNA dots, not rings.
A smear made from an EDTA sample left overnight shows evenly spread red cells with many short, regular projections. The cells look normal in a fresh wet preparation. This is most likely:
Crenated cells (echinocytes) commonly form in vitro from prolonged storage, alkaline glass or slow drying, and disappear in fresh wet mounts. Acanthocytes in spur cell anemia or abetalipoproteinemia are present in vivo and persist in wet preparations.
In a patient with homozygous HbC, especially after splenectomy, the smear may show:
HbC is less soluble and can form dense, 'bar of gold' hexagonal crystals, together with many target cells. Golf ball inclusions are HbH precipitates in alpha-thalassemia.