This program entitled Inclusions Found in Red Blood Cells describes the inclusions found in red cells in disease that are often helpful in establishing a diagnosis. Wright's stained smears of normal blood contain rare, if any, microscopic inclusions in erythrocytes. With special stains one may see a few reticulocytes (less than 2.5%), a rare siderocyte (red cell containing iron granules), and less than 1% Heinz bodies (found in senescent red cells). Most often inclusion bodies are observed in hemolytic anemias, anemias associated with disordered hemoglobin synthesis, drug or chemical toxicity, and following splenectomy. The spleen is important in that it removes foreign bodies from red cells by pitting, similar to removing a seed from a cherry.
In addition to the well-recognized inclusion bodies, erythrocytes may contain extraneous substances. Other than inclusions, crystals of hemoglobin C in hemoglobin C disease, parasites in malaria, and bacteria in Bartonella infections may be seen. The blood smear also may contain nucleated red blood cells. Nucleated red cells are always abnormal if found in the peripheral blood.
The hemoglobinopathies are a subject unto themselves but I have included two test results for sickling, which you might never see unless you work in a hospital laboratory. The metabisulfite test, which is demonstrated below, is not often used now as it is tedious but it can detect true sickling. The test depends upon the reduction of hemoglobin S (Hb S) in a sealed chamber. The preparation is observed for sickling with the microscope. The turbidity test is the one used in many clinical laboratories for screening for sickling. The test is rapid and easy to perform. It depends upon the insolubility of Hb S. False-positive results are common due to interfering substances. In all cases if the turbidity test is positive the hemoglobin must be subjected to electrophoresis to determine the presence of Hb S.
The initial four slides and the other six question slides in the program are questions concerning intraerythrocytic bodies. All of the photomicrographs have been taken at 1000x magnification.
Course Section: 02. Inclusions Found in Red Blood Cells
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