Hematology
Which of the following cells is the most common nucleated cell in normal adult bone marrow? A. Myeloblast B. Promyelocyte C. Myelocyte D. Metamyelocyte
D. Metamyelocyte Level 7 Of the given choices, metamyelocytes are the most abundant form seen in a normal bone marrow. Reference interval is 3-20% Myeloblast reference interval is 0-3%. Promyelocyte reference interval is 1-5%. Myelocyte reference interval is 6-17%.
Which compound normally contains the majority of the body's total iron? A. Hemoglobin B. Enzymes C. Myoglobin D. Cytochromes
A. Hemoglobin Level 5 The correct answer here is hemoglobin. In a normal adult two thirds of the iron present is found in the heme portion of hemoglobin. Enzymes are made of proteins and do not incorporate iron into them. Myoglobin is a protein that binds oxygen in the muscles, but is found is smaller quantities than hemoglobin. Cytochromes are heme-containing proteins, but are also found in smaller quantities than hemoglobin.
All of the following statements describe a method by which platelets aid coagulation EXCEPT: A. Lower blood pressure by releasing heparin B. Catalyze coagulation by releasing Platelet Factor 3 C. Cause blood vessels to constrict by releasing serotonin D. Form a plug to stop the flow of blood
A. Lower blood pressure by releasing heparin Level 4 Platelets do not lower blood pressure by releasing heparin. However, they do form a plug to stop the flow of blood, cause blood vessels to constrict by releasing serotonin, and catalyze coagulation by releasing platelet factor 3. Each of these functions aids in the process of coagulation.
What should be added to the cytocentrifuge chamber when preparing slides on serous fluids to aid in the adhesion of cells to the slide and preserve cellular morphology? A. Hyaluronidase B. 22% Albumin C. 10% acetic acid D. Sterile saline
B. 22% Albumin Level 3 10-22% Albumin should be added when preparing serous fluids and CSF. The addition of albumin helps preserve cellular morphology and improves adhesion to the slide. Hyaluronidase can be added to synovial fluids to help overcome the increased viscosity of these fluids during slide preparation. 10% acetic acid can be used as a diluent for grossly bloody serous fluids and CSF. The acetic acid lyses the red blood cells to increase the visualization of the nucleated cells present. Sterile saline can be used to make dilutions of fluids with red blood cell counts less than 5000 cells/mL. This saline dilution also assists with the visualization of the nucleated cells present.
Pelger-Huet anomaly is characterized by which of the following? A. Giant gray-green bodies and giant lysosomes in the cytoplasm of neutrophils B. Bilobed or round nuclei in neutrophils (hyposegmented) C. Dohle-like-bodies in the cytoplasm of neutrophils D. Large purplish granules in the cytoplasm of all leukocytes
B. Bilobed or round nuclei in neutrophils (hyposegmented) Level 3 Pelger-Huet anomaly is an autosomal dominant condition characterized by failure of normal neutrophilic segmentation and the presence of bilobed neutrophils. It is of no clinical significance. Chediak-Higashi syndrome is characterized by giant gray-green bodies and giant lysosomes in the cytoplasm of leukocytes. These bodies are composed of fused granules. May-Hegglin anomaly is characterized by the presence of dohle-like bodies in granulocytes. These inclusions are composed mainly of RNA from the rough endoplasmic reticulum. Alder-Reilly anomaly is characterized by the presence of large purplish granules in the cytoplasm of all leukocytes. The granules are partially degraded mucopolysaccharides that accumulate in the lysosomes.
Which of the following types of anemia can be described as an inherited bone marrow failure syndrome with patients developing dystrophic nails and white patches in the mouth? A. Fanconi anemia B. Dyskeratosis congenita C. Chronic aquired pure red cell aplasia D. Diamond-Blackfan anemia
B. Dyskeratosis congenita Level 5 Dyskeratosis congenita (DC) can be described as a bone marrow failure syndrome that is inherited. Many patients with DC develop aplastic anemia. DC patients also develop physical abnormalities such as leukoplakia in the mouth and tongue along with dystrophic nails. These physical characteristics help differentiate DC from Fanconi anemia.The physical characteristics listed (dystrophic nails and white patches in the mouth) are not associated with Fanconi anemia.Chronic acquired pure red cell aplastic is an acquired disorder, not an inherited one.Persons with Diamond-Blackfan anemia only have red cell aplasia. They tend to have normal WBC and platelet counts which excludes bone marrow failure.
The fibrin clot begins to form when fibrinogen is cleaved resulting in a fibrin monomer, fibrinopeptide A, and fibrinopeptide B fragments. The fibrin monmers sponaneously polymerize due to hydrogen bonding, and then are covalently linked into fibrin polymers by which factor? A. Plasmin B. Factor XIII C. Factor V D. Thrombin
B. Factor XIII Level 6 Factor XIII, or fibrin stabilizing factor, is responsible for polymerizing the cross-linked fibrin strands to form a stable fibrin clot. Factor XIII is activated by thrombin and calcium ions. Plasmin is the enzyme which digests fibrin and fibrinogen, thus dissolving the clot after healing has taken place. Factor V is a coagulation factor in the common pathway which together with activated Factor X helps to convert prothrombin into thrombin. Thrombin is the key enzyme which initially cleaves the fribrinogen into the fibrin monomers, and helps to activate Factor XIII.
Which of the following disorders is characterized by a stem cell mutation due to the PIGA gene that leads to clones of cells that bind abnormally large amounts of complement? A. Spur cell anemia B. Paroxysmal nocturnal hemoglobinuria C. Hereditary acanthocytosis (aka Abetalipoproteinemia) D. Hereditary pyropoikilocytosis
B. Paroxysmal nocturnal hemoglobinuria Level 5 Paroxysmal nocturnal hemoglobinuria (PNH) is the correct answer. PNH is an acquired erythrocyte disorder due to a mutation in the PIGA gene. This causes abnormal differentiated hematopoietic cells to be cloned which bind large amounts of complement. This makes the cells susceptible to hemolysis. Spur cell anemia is an acquired hemolytic anemia due to liver disease in which serum lipoproteins increase. Excessive complement binding is not a characteristic of spur cell anemia. Hereditary acanthocytosis, known as abetalipoproteinemia, is an autosomal recessive disorder distinguished by an absence of ß-lipoprotein and low levels of cholesterol, triglyceride, and phospholipid. It is not characterized by excessive complement binding. Hereditary pyropoikilocytosis is an inherited disorder related to a deficiency in a-spectrin and the presence of a modified spectrin.
The hemoglobin electrophoresis patterns that are shown on the right include controls for A, S, and C; and A and F above and below the patient results. (NOTE: ASC and AF are simply labels for the controls and do not indicate the order of migration.) The patient was tested in duplicate, and the results are in lanes 5 and 6. The patterns on the left are from alkaline hemoglobin electrophoresis, and the patterns on the right are from acid electrophoresis. These are results from the same patient. The patient lanes displayed in these hemoglobin electrophoresis patterns are consistent with what diagnosis? A. HbSA B. HbSD C. HbSS D. HbS/HPFH
C. HbSS Level 4 The patient lanes 5 & 6 show one heavy band of hemoglobin in the "S" position on both alkaline and acid electrophoresis. This is consistent with HbSS or sickle cell anemia. In alkaline hemoglobin electrophoresis, the sample is applied closest to the cathode (negatively charged electrode). Once current is applied, the hemoglobins move toward the anode (positively charged electrode). Based on the hemoglobin controls shown in the alkaline electrophoresis, hemoglobin A is the fastest moving hemoglobin and is represented by the band closest to the anode in lanes 3, 4, 7 & 8. Hemoglobin F is the next fastest and is represented by the band second closest to the anode in lanes 4 & 8. Hemoglobin S is next and is represented by the second band in lanes 3 & 7. Hemoglobin C is the slowest hemoglobin and is represented by the band closest to the cathode in lanes 3 & 7. In acid hemoglobin electrophoresis, the samples are placed near the middle of the gel and migrate toward either the cathode or anode. Based on the hemoglobin controls shown here in the acid electrophoresis, Hemoglobin F migrated toward the cathode and is represented by the band closest to the cathode in lanes 4 & 8. Hemoglobin A also migrates toward the cathode and is the second band closest to the point of origin, as seen in lanes 4 & 8. There are also Hemoglobin A bands that have the same migration pattern in lanes 3 & 7. Hemoglobin S & C migrate towards the anode. Hemoglobin migrates the farthest and is indicated by the largest bands in lanes 3 & 7. Hemoglobin S in the center band is shown in lanes 3 & 7. In HbSA, there would be bands in the A and S positions on both alkaline and acid electrophoresis patterns. In HbSD, there would be one band on the alkaline electrophoresis pattern. Hemoglobin D migrates with S in alkaline electrophoresis. In acid electrophoresis, there would be bands in the A and S positions. Hemoglobin D migrates with A in acid electrophoresis. In HbS/HPFH, there would be two bands in the alkaline and acid electrophoresis patterns; one would be in the S position. Hereditary Persistence of Fetal Hemoglobin (HPFH) will result in bands in the F position.
Which of the following is characteristic of Alder-Reilly anomaly? A. Giant, dysfunctional lysosomal cytoplasmic granules B. Döhle body-like inclusions composed of precipitated myosin heavy chains C. Large, darkly staining cytoplasmic granules composed of partially digested mucopolysaccharides D. Decreased nuclear segmentation and coarse chromatin in leukocytes
C. Large, darkly staining cytoplasmic granules composed of partially digested mucopolysaccharides Level 6 Alder-Reilly anomaly is characterized by large, darkly staining cytoplasmic granules composed of partially digested mucopolysaccharides. These granules resemble toxic granulation in neutrophils, but findings commonly associated with toxic granulation, such as Döhle bodies, neutrophilia, and a left shift, are absent in Alder-Reilly anomaly. The granules of Alder-Reilly anomaly may also be found in lymphocytes and monocytes; toxic granulation is exclusive to neutrophils. Leukocyte function is normal in Alder-Reilly anomaly. Giant, dysfunctional lysosomal cytoplasmic granules are seen in Chédiak-Higashi syndrome. These granules are seen in granulocytes, monocytes, and lymphocytes. Leukocyte dysfunction leads to recurrent pyogenic infection and early death. Döhle body-like inclusions composed of precipitated myosin heavy chains are seen in May-Hegglin anomaly, along with variable thrombocytopenia and giant platelets. These inclusions are seen in granulocytes and monocytes. Decreased nuclear segmentation and coarse chromatin in leukocytes is seen in Pelger-Huët anomaly (PHA). Morphologic changes are most obvious in mature neutrophils.
A patient has a history of repeated spontaneous abortion. Coagulation studies reveal an elevated APTT, normal PT, normal platelet function, and normal thrombin time. Schistocytes were seen on the peripheral blood smear. Which test should be performed to determine if the patient has lupus anticoagulant? A. Factor VIII assay B. Mixing studies with factor-deficient plasmas C. Antinuclear antibody test D. Platelet neutralization test
D. Platelet neutralization test Level 8 Platelet neutralization tests are one of the confirmatory tests that can be used to determine if a patient has a circulating lupus antibody, or lupus anticoagulant. The principle in this test involves the use of a freeze-thawed platelet suspension that, when mixed with the patient plasma, will neutralize the anti-phospholipid antibodies (lupus anticoagulant) present and allow for a corrected APTT result upon re-testing. A Factor VIII assay would be abnormal due to the interference of the lupus anticoagulant with the phospholipid in the APTT test that is used to measure Factor VIII activity. Mixing studies are useful as screening tests for lupus anticoagulant and phospholipid antibodies. Mixing studies with factor deficient plasmas and the APTT test would all be abnormal due to the interference of the lupus anticoagulant with the phospholipid in the APTT test that is used to perform the mixing studies. A mixing study using the patient's plasma incubated 1:1 with normal plasma would also be abnormal (uncorrected). The antinuclear antibody test is a screening test for autoimmune diseases such as systemic lupus erythematosus (SLE). Although some patients with SLE may have a lupus anticoagulant, not all patients with lupus anticoagulant have SLE.
