Question 1

Explain how methemoglobin is formed, and how its presence impacts oxygen delivery.Be sure to include oxygen affinity in your answer.

Accepted Answer

Methemoglobin is formed by oxidation of ferrous iron to ferric iron in the hemoglobin molecule.As a result, it cannot effectively transport oxygen, due to poor oxygen affinity.Patients with this abnormal hemoglobin will have cyanosis and shortness of breath as a result of poor oxygen transport.

Question 2

Which of the following has the highest prevalence worldwide?

Accepted Answer

A) Hgb S 
B) Hgb C 
C) Hgb D 
D) Hgb E 
A) Hgb S 
B) Hgb C 
C) Hgb D 
D) Hgb E A

Question 3

How is methemoglobin detected in the laboratory?

Accepted Answer

Spectral analysis at 450 nm will detect methemoglobin.

Question 4

Use this case to answer the following questions:
A 2-year-old black male was being evaluated at the County Clinic for swollen hands and feet that were extremely painful. Upon physical examination, the child was found to have a fever and hepatosplenomegaly, and was physically small for his age. The child was of Jamaican descent.
Patient history revealed that the child was normal for his birth weight, but since then, he was consistently underweight and undersized for his age group. Family history was not readily available. The physician had the child admitted to the hospital for workup and ordered the following CBC. 
 $\begin{array}{ll}
\text { TEST } & \text { RESULTS } \
\text { WBC } & 16.6 \times 10^{9} / \mathrm{L} \
\text { RBC } & 2.53 \times 10^{12} / \mathrm{L} \
\text { HGB } & 7.5 \mathrm{gm} / \mathrm{dL} \
\text { HCT } & 21.4 \% \
\text { MCV } & 84.6 \mathrm{fl} \
\text { MCH } & 18.9 \mathrm{pg} \
\text { MCHC } & 35.0 \mathrm{~g} / \mathrm{dL} \
\text { RDW } & 18.9 \
\text { PLT } & 511 \times 10^{9} / \mathrm{L}\
\text { Differential: }\
\text { Polys } & 84 \% \
\text { Stabs } & 10 \% \
\text { Lymphs } & 5 \% \
\text { Eos } & 1 \% \
\text { NRBCs } & 12
\end{array}$
-Hemoglobinopathy results from a genetic abnormality of which structure within the hemoglobin molecule?

Accepted Answer

A) Globin chain 
B) Heme 
C) Porphyrin 
D) Iron 
A) Globin chain 
B) Heme 
C) Porphyrin 
D) Iron

Question 5

Use this case to answer the following questions:
A 2-year-old black male was being evaluated at the County Clinic for swollen hands and feet that were extremely painful. Upon physical examination, the child was found to have a fever and hepatosplenomegaly, and was physically small for his age. The child was of Jamaican descent.
Patient history revealed that the child was normal for his birth weight, but since then, he was consistently underweight and undersized for his age group. Family history was not readily available. The physician had the child admitted to the hospital for workup and ordered the following CBC. 
 $\begin{array}{ll}
\text { TEST } & \text { RESULTS } \
\text { WBC } & 16.6 \times 10^{9} / \mathrm{L} \
\text { RBC } & 2.53 \times 10^{12} / \mathrm{L} \
\text { HGB } & 7.5 \mathrm{gm} / \mathrm{dL} \
\text { HCT } & 21.4 \% \
\text { MCV } & 84.6 \mathrm{fl} \
\text { MCH } & 18.9 \mathrm{pg} \
\text { MCHC } & 35.0 \mathrm{~g} / \mathrm{dL} \
\text { RDW } & 18.9 \
\text { PLT } & 511 \times 10^{9} / \mathrm{L}\
\text { Differential: }\
\text { Polys } & 84 \% \
\text { Stabs } & 10 \% \
\text { Lymphs } & 5 \% \
\text { Eos } & 1 \% \
\text { NRBCs } & 12
\end{array}$
-Based on these findings, what test would be the logical next step?

Accepted Answer

A) Bone marrow aspirate 
B) Osmotic fragility 
C) Sickle solubility test 
D) Peripheral blood smear 
A) Bone marrow aspirate 
B) Osmotic fragility 
C) Sickle solubility test 
D) Peripheral blood smear

Question 6

A patient has a positive sickle solubility test.Further investigation reveals hemoglobin of 8.5 g/dL.What can be done to confirm these findings? Explain your answer.

Accepted Answer

The positive sickle solubility test can

Question 7

Patients with sickle-cell disease and those with sickle-cell trait differ greatly in clinical presentation.List at least two features in clinical presentation, and explain why they differ.

Accepted Answer

Patients with sickle-cell disease report

Question 8

Use this case to answer the follwing questions:
During a discussion of RBC indices, a medical technologist of Cambodian origin mentioned that her own red cells were small in a CBC per?formed two years earlier in a routine physical. A more recent CBC showed the following results.
 $\begin{array}{ll}
\text { TEST } & \text { RESULTS } \
\text { WBC } & 9.3 \times 10^{9} / \mathrm{L} \
\text { RBC } & 6.11 \times 10^{12} / \mathrm{L} \
\mathrm{HGB} & 13.0 \mathrm{~g} / \mathrm{dL} \
\mathrm{HCT} & 41.8 \% \
\text { MCV } & 69.6 \mathrm{fL} \
\text { MCH } & 22.5 \mathrm{pg} \
\text { MCHC } & 31.0 \mathrm{~g} / \mathrm{dL} \
\mathrm{RDW} & 15.8 \
\mathrm{PLT} & 351 \times 10^{9} / \mathrm{L}\
\text { Differential }& \text { Within normal limits }\
\end{array}$
-What reflex test is most appropriate to investigate these results?

Accepted Answer

A) Hemoglobin electrophoresis and iron studies 
B) Bone marrow aspirate 
C) Vitamin B?? and folate assays 
D) Cytogenetic analysis 
A) Hemoglobin electrophoresis and iron studies 
B) Bone marrow aspirate 
C) Vitamin B?? and folate assays 
D) Cytogenetic analysis

Question 9

Hemoglobinopathies are detected by which laboratory method?

Accepted Answer

A) Spectrophotometric analysis at 450 nm 
B) Careful examination of peripheral blood cellular components 
C) Separation and quantification of protein subunits through an electrical field 
D) Turbidimetric analysis of whole blood 
A) Spectrophotometric analysis at 450 nm 
B) Careful examination of peripheral blood cellular components 
C) Separation and quantification of protein subunits through an electrical field 
D) Turbidimetric analysis of whole blood

Question 10

Thalassemias are produced as a result of:

Accepted Answer

A) Quantitative defects in globin chain synthesis. 
B) Qualitative defects in globin chain synthesis. 
C) Structural defects in heme synthesis. 
D) Molecular defects in hemoglobin synthesis. 
A) Quantitative defects in globin chain synthesis. 
B) Qualitative defects in globin chain synthesis. 
C) Structural defects in heme synthesis. 
D) Molecular defects in hemoglobin synthesis.

Question 11

In hemoglobin C disease, the life span of the cell is decreased to what length?

Accepted Answer

A) 90-120 days 
B) 7-10 days 
C) 75-90 days 
D) 30-55 days 
A) 90-120 days 
B) 7-10 days 
C) 75-90 days 
D) 30-55 days

Question 12

If a patient had hemoglobin S and hemoglobin A identified by electrophoresis and a positive hemoglobin solubility test, what is the most likely condition of the patient?

Accepted Answer

A) Hemoglobin C trait 
B) Hemoglobin S/D disease 
C) Hemoglobin SC disease 
D) Sickle-cell trait 
A) Hemoglobin C trait 
B) Hemoglobin S/D disease 
C) Hemoglobin SC disease 
D) Sickle-cell trait

Question 13

In Hemoglobin C disease how does the mutation affect the hemoglobin molecule?

Accepted Answer

A) It cannot carry oxygen. 
B) It forms insoluble aggregates. 
C) It is unstable. 
D) It has increased oxygen affinity. 
A) It cannot carry oxygen. 
B) It forms insoluble aggregates. 
C) It is unstable. 
D) It has increased oxygen affinity.

Question 14

Both hemoglobin D and G migrate with which hemoglobin on alkaline gel electrophoresis?

Accepted Answer

A) S 
B) A 
C) F 
D) C 
A) S 
B) A 
C) F 
D) C

Question 15

Other than hemoglobin S, name two abnormal hemoglobins that produce a positive sickle solubility test.Explain how they could be differentiated from HbS.

Accepted Answer

Hemoglobins C-Harlem and HbI have positi

Question 16

Disease that results from a molecular defect in hemoglobin synthesis in RBCs is termed:

Accepted Answer

A) Thalassemia. 
B) Hemoglobinopathy. 
C) Porphyria. 
D) Asynchrony. 
A) Thalassemia. 
B) Hemoglobinopathy. 
C) Porphyria. 
D) Asynchrony.

Question 17

Electrophoresis at an acid pH using a citrate agar gel separates what hemoglobin variants that travel together on cellulose acetate at pH 8.6?

Accepted Answer

A) Hemoglobins A and S 
B) Hemoglobins S and C 
C) Hemoglobins D and S 
D) Hemoglobins E and A 
A) Hemoglobins A and S 
B) Hemoglobins S and C 
C) Hemoglobins D and S 
D) Hemoglobins E and A

Question 18

What is the purpose of treating sickle-cell patients with hydroxyurea?

Accepted Answer

A) To dilute the amount of sickled red blood cells 
B) To destroy the sickling red blood cells by initiating an immune response 
C) To convert Hgb S into Hgb A 
D) To increase the level of hemoglobin F that will reduce intracellular sickling 
A) To dilute the amount of sickled red blood cells 
B) To destroy the sickling red blood cells by initiating an immune response 
C) To convert Hgb S into Hgb A 
D) To increase the level of hemoglobin F that will reduce intracellular sickling

Question 19

The peripheral blood smear contains a normocytic, normochromic morphology with marked reticulocytosis.The hemoglobin solubility test is positive.What confirmatory test should follow?

Accepted Answer

A) Bilirubin analysis 
B) Haptoglobin analysis 
C) Hemoglobin electrophoresis 
D) Bone marrow aspiration 
A) Bilirubin analysis 
B) Haptoglobin analysis 
C) Hemoglobin electrophoresis 
D) Bone marrow aspiration

Question 20

Hemoglobin C disease has altered solubility properties similar to hemoglobin S disease.What accounts for this altered solubility?

Accepted Answer

A) Heme iron is in the ferric from rather than ferrous form. 
B) The hemoglobin remains in the tense structure. 
C) A nonploar amino acid is substituted for a polar amino acid. 
D) A polar amino acid is substituted near the pocket where heme binds. 
A) Heme iron is in the ferric from rather than ferrous form. 
B) The hemoglobin remains in the tense structure. 
C) A nonploar amino acid is substituted for a polar amino acid. 
D) A polar amino acid is substituted near the pocket where heme binds.

Exam 10: Hemoglobinopaties: Qualitative Defects

Explain how methemoglobin is formed, and how its presence impacts oxygen delivery.Be sure to include oxygen affinity in your answer.

Which of the following has the highest prevalence worldwide?

How is methemoglobin detected in the laboratory?

A patient has a positive sickle solubility test.Further investigation reveals hemoglobin of 8.5 g/dL.What can be done to confirm these findings? Explain your answer.

Patients with sickle-cell disease and those with sickle-cell trait differ greatly in clinical presentation.List at least two features in clinical presentation, and explain why they differ.

Hemoglobinopathies are detected by which laboratory method?

Thalassemias are produced as a result of:

In hemoglobin C disease, the life span of the cell is decreased to what length?

If a patient had hemoglobin S and hemoglobin A identified by electrophoresis and a positive hemoglobin solubility test, what is the most likely condition of the patient?

In Hemoglobin C disease how does the mutation affect the hemoglobin molecule?

Both hemoglobin D and G migrate with which hemoglobin on alkaline gel electrophoresis?

Other than hemoglobin S, name two abnormal hemoglobins that produce a positive sickle solubility test.Explain how they could be differentiated from HbS.

Disease that results from a molecular defect in hemoglobin synthesis in RBCs is termed:

Electrophoresis at an acid pH using a citrate agar gel separates what hemoglobin variants that travel together on cellulose acetate at pH 8.6?

What is the purpose of treating sickle-cell patients with hydroxyurea?

The peripheral blood smear contains a normocytic, normochromic morphology with marked reticulocytosis.The hemoglobin solubility test is positive.What confirmatory test should follow?

Hemoglobin C disease has altered solubility properties similar to hemoglobin S disease.What accounts for this altered solubility?

Introduction

Cellular Homeostasis

Hematopoiesis

Structure and Function of Hematopoietic Organs

The Erythrocyte

Hemoglobin

The Leukocyte

Introduction to Anemia

Anemias of Disordered Iron Metabolism and Heme Synthesis

Thalassemia

Megaloblastic and Nonmegaloblastic Macrocytic Anemias

Introduction to Hemolytic Anemia

Hemolytic Anemia: Membrane Defects

Hemolytic Anemia: Enzyme Deficiencies

Hemolytic Anemia: Immune Anemias

Hemolytic Anemia: Nonimmune Defects

Nonmalignant Granulocyte and Monocyte Disorders

Nonmalignant Lymphocyte Disorders

Introduction to Hematopoietic Neoplasms

Myeloproliferative Disorders

Myelodysplastic Syndromes

Acute Myeloid Leukemias

Acute Lymphoblastic Leukemias

Lymphoid Malignancies: Chronic Lymphoid Leukemias, Lymphomas, and Plasma Cell Neoplasms

Hematopoietic Stem Cell Transplantation

Morphologic Analysis of Body Fluids in the Hematology Laboratory

Primary Hemostasis

Secondary Hemostasis and Fibrinolysis

Disorders of Primary Hemostasis

Disorders of Secondary Hemostasis

Thrombophilia

Hematology Procedures and Hemostasis

Bone Marrow Examination

Automation in Hematology and Hemostasis

Flow Cytometry

Chromosome Analysis of Hematopoietic and Lymphoid Disorders

Molecular Analysis of Hematologic Diseases

Laboratory Testing in Coagulation

Quality Assessment in the Hematology Laboratory

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