1.
Insufficient centrifugation will result in:
Correct Answer
A. A false increase in Hct value
Explanation
Insufficient centrifugation can result in a false increase in Hct value. Centrifugation is a process used to separate the components of blood, including red blood cells and plasma. If the centrifugation is not done properly or for a sufficient amount of time, it may not effectively separate the components, leading to a false increase in the hematocrit (Hct) value. This means that the Hct value may appear higher than it actually is, potentially leading to inaccurate diagnostic or clinical decisions.
2.
Erythrocytes that vary in size from the normal 6-8 um are described as exhibiting:
Correct Answer
A. Anisocytosis
Explanation
Erythrocytes that vary in size from the normal 6-8 um are described as exhibiting anisocytosis. Anisocytosis refers to the presence of red blood cells that are of unequal sizes. This condition can be seen in various disorders, such as iron deficiency anemia, vitamin B12 deficiency, and liver disease. Anisocytosis is typically observed through a blood smear examination, where the red blood cells can be seen to have different sizes.
3.
Which of the following is the preferable site for bone marrow aspiration and biopsy in an adult?
Correct Answer
A. Iliac crest
Explanation
The iliac crest is the preferable site for bone marrow aspiration and biopsy in an adult. This is because it provides easy access to the bone marrow, which is located in the spongy part of the bone. The iliac crest is a flat, broad bone located in the pelvic region, making it a suitable site for the procedure. The sternum, tibia, and spinous processes of the vertebra are not commonly used for bone marrow aspiration and biopsy in adults.
4.
Mean cell volume (MCV) is calculated using the following:
Correct Answer
B. (Hct/RBC)x10
Explanation
The correct answer is (Hct/RBC)x10. Mean cell volume (MCV) is a measure of the average size of red blood cells. It is calculated by dividing the hematocrit (Hct), which is the percentage of red blood cells in the total blood volume, by the red blood cell count (RBC) and then multiplying by 10. This calculation gives the average volume of each red blood cell. Therefore, (Hct/RBC)x10 is the correct formula to calculate MCV.
5.
What term describes the change in shape of erythrocytes seen on a Wright's-stained peripheral blood smear:
Correct Answer
A. Poikilocytosis
Explanation
Poikilocytosis is the correct term to describe the change in shape of erythrocytes seen on a Wright's-stained peripheral blood smear. Poikilocytosis refers to the presence of abnormally shaped red blood cells, which can include cells that are elongated, oval, teardrop-shaped, or have other irregular shapes. This term is commonly used in the context of evaluating blood smears for various blood disorders, such as anemia or certain genetic conditions. Anisocytosis refers to variation in red blood cell size, hypochromia refers to decreased staining of red blood cells, and polychromasia refers to variation in red blood cell color.
6.
Calculate the mean cell hemoglobin concentration (MCHC) using the following values:
Hgb: 15 g/dL
RBC: 4.50 x 10^6/uL
Hct: 47 mL/dL
Correct Answer
C. 31.9% (.319)
Explanation
MCHC is the average concentration of Hgb in red cells expressed by a percent. It expresses the ratio of the weight of Hgb to the volume of erythrocytes and is calculated by dividing Hgb by Hct and then multiplying by 100.
(15/47)x100=31.9%
7.
A manual white blood cell count was performed. A total of 36 cells were counted in all 9-mm^2 squares of a Neubauer-ruled hemacytometer. A 1:10 dilution was used. White is the WBC?
Correct Answer
A. 0.4x10^9/L
Explanation
Number of cells counted X dilution factor X depth factor / area
36 x 10 x 10 = 3600 / 400/mm^3 or 0.4 x 10^9 L
8.
When an erythrocyte containing iron granules is stained with Prussian blue, the cell is called a:
Correct Answer
D. Siderocyte
Explanation
When an erythrocyte containing iron granules is stained with Prussian blue, the cell is called a siderocyte. Siderocytes are characterized by the presence of iron granules, which can be visualized using the Prussian blue stain. Spherocytes, leptocytes, and schistocytes refer to different types of abnormal red blood cells with specific morphological features, but they do not specifically indicate the presence of iron granules.
9.
A 7.0 mL etheylenediaminetetraacetic acid (EDTA) tube is received in teh lab containing only 2.0 mL of blood. If the lab is using manual techniques, which of the following tests will most likely be erroneous?
Correct Answer
C. Hct
Explanation
If the lab is using manual techniques and only 2.0 mL of blood is received in a 7.0 mL EDTA tube, the Hct (hematocrit) test will most likely be erroneous. The Hct test measures the percentage of red blood cells (RBCs) in the total volume of blood. Since there is a smaller amount of blood in the tube, the measured Hct value will be higher than the actual value, leading to an inaccurate result.
10.
A 1:200 dilution of a patient sample was made and 336 red cells were counted in an area of 0.2 mm^2. What is the RBC count?
Correct Answer
B. 3.36 x 10^12/L
Explanation
A 1:200 dilution means that the original concentration of red blood cells (RBCs) in the patient sample was diluted 200 times. Therefore, to find the RBC count, we need to multiply the number of RBCs counted in the diluted sample by the dilution factor. In this case, 336 RBCs were counted in an area of 0.2 mm^2. Since the area is known, we can calculate the RBC count per mm^2 by dividing 336 by 0.2, which equals 1680 RBCs/mm^2. To convert this to RBC count per liter, we need to multiply by the conversion factor, which is 10^12. Therefore, the RBC count is 1.68 x 10^12/L.
11.
What phagocytic cells produce lysozymes that are bacteriocidal?
Correct Answer
D. NeutropHils
Explanation
Neutrophils are phagocytic cells that produce lysozymes, which are enzymes that have bacteriocidal properties. These lysozymes help in the destruction of bacteria by breaking down their cell walls. Neutrophils are an important part of the immune system and are involved in the initial response to infection and inflammation.
12.
If a patient has a retic count of 7% and a Hct of 20% what is the corrected retic count?
Correct Answer
B. 3.1%
Explanation
Corrected retic count is: retic percent x Hct / 45 (average normal Hct) = Answer
7 x (20 / 45) = 3.1
13.
A decreased osmotic fragility test would be associated with which of the following conditions?
Correct Answer
A. Sickle cell anemia
Explanation
A decreased osmotic fragility test is associated with sickle cell anemia. Sickle cell anemia is a genetic disorder characterized by the presence of abnormal hemoglobin, which causes red blood cells to become rigid and sickle-shaped. These sickle-shaped cells are less fragile and more resistant to osmotic stress, resulting in a decreased osmotic fragility test.
14.
What effect would using a buffer at pH 6.0 have on a Wright's-stained smear?
Correct Answer
C. Red cells would be stained too blue
Explanation
Using a buffer at pH 6.0 for a Stained smear would likely result in the effect that "Red cells would be stained to blue." Wright's stain is commonly used in hematology to stain blood cells, and the pH of the staining solution can impact the staining process. A buffer at pH 6.0 is more acidic, and in this acidic environment, red blood cells tend to take up the blue stain more intensely, resulting in a blue coloration. White cell cytoplasm is usually stained pink in Wright's stain, so a lower pH is not expected to significantly affect the coloration of white cell cytoplasm.
The staining process itself would not cause red cells to lyse on the slide; rather, it affects the coloration of the cells.
15.
Which of the following erythrocyte inclusions can be visualized with supravital stain but cannot be detected on a Wright's stained blood smear?
Correct Answer
B. Heinz bodies
Explanation
Heinz bodies are denatured hemoglobin that form within red blood cells due to oxidative damage. They can be visualized using supravital stains, which are dyes that are taken up by living cells. However, they cannot be detected on a Wright's stained blood smear, which is a commonly used staining technique for visualizing blood cells. This is because Wright's stain primarily stains the cytoplasm of the red blood cells, making it difficult to detect the presence of Heinz bodies.
16.
A falsely elevated Hct is obtained. Which of the following calculated values will not be affected?
Correct Answer
B. MCH
Explanation
An elevated Hct indicates an increase in the proportion of red blood cells in the blood. MCH (mean corpuscular hemoglobin) is a calculated value that measures the average amount of hemoglobin in each red blood cell. Since MCH is calculated based on the amount of hemoglobin and not the proportion of red blood cells, it will not be affected by a falsely elevated Hct. Therefore, MCH will remain unchanged in this scenario.
17.
A Miller disk is an ocular device used to facilitate counting of:
Correct Answer
B. Reticulocytes
Explanation
A Miller disk is an ocular device used to facilitate counting of reticulocytes. Reticulocytes are immature red blood cells that still contain some organelles, such as ribosomes. They are important in evaluating bone marrow function and diagnosing certain types of anemia. The Miller disk helps in distinguishing reticulocytes from mature red blood cells by providing a grid pattern that allows for accurate counting.
18.
RBC indices obtained on a patient are as follows:
MCV: 88 um^3
MCH: 30 pg
MCHC: 34%
The RBC on the peripheral smear would appear:
Correct Answer
C. Normocytic, normochromic
Explanation
Based on the given RBC indices, the MCV (mean corpuscular volume) is within the normal range (80-100 um^3), indicating that the RBCs are of normal size. The MCH (mean corpuscular hemoglobin) is also within the normal range (27-34 pg), suggesting that the amount of hemoglobin in each RBC is normal. Lastly, the MCHC (mean corpuscular hemoglobin concentration) is also within the normal range (32-36%), indicating that the concentration of hemoglobin in each RBC is normal. Therefore, the RBCs on the peripheral smear would appear normocytic (normal size) and normochromic (normal hemoglobin concentration).
19.
All of the following factors may influence the ESR except:
Correct Answer
A. Blood drawn in a sodium citrate tube
Explanation
The ESR, or erythrocyte sedimentation rate, is a measure of how quickly red blood cells settle in a tube over a certain period of time. It is a non-specific marker of inflammation and is influenced by various factors. Anisocytosis and poikilocytosis refer to abnormal variations in the size and shape of red blood cells, which can affect the ESR. Plasma proteins, specifically fibrinogen, can also impact the rate at which red blood cells settle. The caliber of the tube can affect the distance the red blood cells have to travel, thus influencing the ESR. However, blood drawn in a sodium citrate tube does not influence the ESR as sodium citrate is an anticoagulant and does not affect the sedimentation rate of red blood cells.
20.
What staining method is used most frequently to stain and count reticulocytes?
Correct Answer
B. Supravital staining
Explanation
Supravital staining is the most frequently used staining method to stain and count reticulocytes. This technique involves staining living cells with vital dyes that can penetrate the cell membrane and bind to specific cellular components. It allows the visualization and enumeration of reticulocytes, which are immature red blood cells, based on their ability to retain RNA. Immunofluorescence staining uses fluorescently labeled antibodies to detect specific proteins, while Romanowsky staining and cytochemical staining are used for staining blood smears to visualize different cellular components.
21.
The Coulter principle for counting cells is based upon the fact that:
Correct Answer
A. Isotonic solutions conduct electricity better than cells do
Explanation
The Coulter principle for counting cells is based upon the fact that isotonic solutions conduct electricity better than cells do. This principle relies on the fact that when a cell passes through a small aperture in an electrical current, it causes a disruption in the current, resulting in a measurable change in electrical resistance. By comparing the changes in resistance caused by cells to those caused by isotonic solutions, the number of cells can be accurately counted.
22.
A correction is necessary for WBC counts when nucleated RBC are seen on the peripheral smear because:
Correct Answer
C. Nucleated RBC's are counted as leukocytes
Explanation
Nucleated RBC's are counted as leukocytes. This means that when nucleated RBC's are seen on the peripheral smear, they are mistakenly included in the WBC count, leading to an artificially higher WBC count. Therefore, a correction is necessary to accurately determine the WBC count by excluding the nucleated RBC's from the count.
23.
Using a Coulter counter analyzer, an increased RDW should correlate with:
Correct Answer
B. Anisocytosis
Explanation
An increased RDW (red cell distribution width) indicates the presence of red blood cells of varying sizes. Anisocytosis refers to the condition where red blood cells are of unequal sizes. Therefore, an increased RDW is expected to correlate with anisocytosis.
24.
Given the following values, which set of red blood cell indicies suggests spherocytosis?
Correct Answer
C. MCV 80 um^3 MCH 36.5 pg MCHC 39%
Explanation
Spherocytes have a decreased cell diameter and volume, which results in loss of central pallor and discoid shape. The index most affected is the MCHC, usually bein in excess of 36%.
25.
Which of the following statistical terms reflects the best index of precision?
Correct Answer
C. Coefficient of variation
Explanation
The coefficient of variation reflects the best index of precision because it measures the relative variability of a dataset. It is calculated by dividing the standard deviation by the mean, and then multiplying by 100 to express it as a percentage. This allows for the comparison of variability between datasets with different means. A lower coefficient of variation indicates a higher precision, as it suggests that the data points are closer to the mean and have less variability. Therefore, the coefficient of variation is the most suitable statistical term for assessing precision.
26.
Which of the following is considered a normal hemoglobin?
Correct Answer
D. Deoxyhemoglobin
Explanation
Deoxyhemoglobin is considered a normal hemoglobin because it is the form of hemoglobin that lacks oxygen. It is formed when oxygen is released from oxygenated hemoglobin in the tissues. Deoxyhemoglobin is essential for the transportation of carbon dioxide from the tissues back to the lungs. It plays a crucial role in the oxygenation and deoxygenation process in the body.
27.
Which condition will shift the oxyhemoglobin dissociation curve to the right?
Correct Answer
A. Acidosis
Explanation
Acidosis is a condition characterized by an increase in the acidity of the blood. This decrease in pH causes a shift in the oxyhemoglobin dissociation curve to the right. This means that hemoglobin has a decreased affinity for oxygen, resulting in increased release of oxygen to the tissues. This shift is beneficial as it allows for enhanced oxygen unloading in tissues with high metabolic demands, such as during exercise or in areas of low oxygen tension.
28.
Which is the major type of leukocyte seen in the peripheral smear of a patient with aplastic anemia?
Correct Answer
B. LympHocyte
Explanation
In aplastic anemia, the bone marrow fails to produce enough blood cells, including leukocytes. Lymphocytes are a major type of leukocyte that plays a crucial role in the immune system. They are responsible for recognizing and destroying foreign substances in the body. In aplastic anemia, lymphocytes are often seen in higher numbers in the peripheral smear as the bone marrow tries to compensate for the decreased production of other types of leukocytes. Therefore, lymphocyte is the major type of leukocyte seen in the peripheral smear of a patient with aplastic anemia.
29.
What is the normal WBC differential lymphocyte percentage (range) in the adult population?
Correct Answer
A. 20-50%
Explanation
The normal WBC differential lymphocyte percentage in the adult population is 20-50%. This means that lymphocytes, a type of white blood cell, make up 20-50% of the total white blood cell count. Lymphocytes are an important part of the immune system and play a crucial role in fighting off infections and diseases. This range is considered normal and indicates a healthy immune system.
30.
In which age group would 60% lymphocytes be a normal finding?
Correct Answer
C. 6 months - 2 years
Explanation
Lymphocytes are a type of white blood cells that play a crucial role in the immune system. In infants and young children, lymphocyte counts tend to be higher compared to older age groups. Therefore, it is normal to have a higher percentage of lymphocytes in the blood of children aged 6 months to 2 years.
31.
Which of the following results on an automated differential suggests that a peripheral smear should be review manually?
Correct Answer
C. Mono 15%
Explanation
A peripheral smear should be reviewed manually when there is an abnormal result in the automated differential. In this case, the result of Mono 15% suggests that a manual review is necessary. The percentage of monocytes is outside the normal range, indicating a potential abnormality that needs to be further evaluated.
32.
In which stage of erythrocytic maturation does Hgb formation begin?
Correct Answer
D. Polychromatic normoblast
Explanation
Hemoglobin (Hgb) formation begins in the polychromatic normoblast stage of erythrocytic maturation. This stage is characterized by the synthesis of Hgb, which is an essential component of red blood cells. The polychromatic normoblast is a precursor cell that has already undergone several stages of maturation and is now actively producing Hgb. As the cell progresses through further stages of maturation, it eventually loses its nucleus and other organelles to become a mature red blood cell.
33.
Which of the following can shift the hemoglobin-oxygen dissociation curve to the right?
Correct Answer
D. All of the above
Explanation
Increases in 2,3 DPG, acidosis, and hypoxia can all shift the hemoglobin-oxygen dissociation curve to the right. 2,3 DPG is a molecule that binds to hemoglobin and reduces its affinity for oxygen, causing more oxygen to be released to the tissues. Acidosis, which is an increase in acidity, also decreases hemoglobin's affinity for oxygen. Hypoxia, which is a decrease in oxygen levels, stimulates the production of 2,3 DPG and further shifts the curve to the right. Therefore, all three factors can independently or together shift the curve to the right, resulting in increased oxygen release to the tissues.
34.
Which of the following Hbg configurations is characteristic of Hgb H?
Correct Answer
C. B4
Explanation
The correct answer is B4. This configuration is characteristic of Hgb H because it indicates the presence of four beta-globin chains. Hgb H is a condition where there is an excess of beta-globin chains due to a deletion of three alpha-globin genes. This leads to the formation of abnormal tetramers of beta-globin chains, known as Hgb H. The B4 configuration represents the presence of four beta-globin chains, which is consistent with Hgb H.
35.
Autoagglutination of red cells at room temp can result in which of the following?
Correct Answer
D. All of the above
Explanation
Autoagglutination of red cells at room temperature can result in low RBC count, high MCV, and low hematocrit. Autoagglutination occurs when the red blood cells clump together, leading to a decrease in the number of individual cells available for counting, hence resulting in a low RBC count. The clumping of cells also affects the measurement of the mean corpuscular volume (MCV), which is a measure of the average size of red blood cells. The agglutinated cells may appear larger, leading to a higher MCV. Additionally, the clumping can also cause a decrease in the proportion of red blood cells in the total blood volume, resulting in a low hematocrit.