Deck 27: Hemoglobinopathies (Structural Defects in Hemoglobin)

Question 1

A patient has target cells and a positive tube solubility test.This patient probably

A)is normal.
B)has sickle cell anemia.
C)has sickle trait.
D)has either sickle cell anemia or trait.

Answer 1

has either sickle cell anemia or trait.

Question 2

Which of the following would be unexpected in homozygous Hb S?

A)high reticulocyte count
B)hemoglobin A (Hb A)
C)elevated hemoglobin F (Hb F)
D)hemoglobin that is less soluble

Answer 2

hemoglobin A (Hb A)

Question 3

Sickle cell presence in the blood results in all of the following except

A)decrease in blood viscosity.
B)decrease in oxygen tension.
C)decrease in blood pH.
D)increase in 2,3-biphosphoglycerate .

Answer 3

decrease in blood viscosity.

Question 4

What clinical feature of sickle cell disease accounts for the highest number of hospital admissions?

A)megaloblastic crisis
B)vasoocclusion
C)autosplenectomy
D)hand-foot dactylitis

Question 5

Cellulose acetate is performed on a patient with known homozygous Hb S who has received red cell transfusions in the past week.What hemoglobins would be expected to be found?

A)Hb S and Hb F
B)Hb A and Hb F
C)Hb S, Hb A, and Hb F
D)Hb S, Hb A, Hb F, and Hb A2

Question 6

Which of the following is a typical finding in patients with Hb M?

A)severe anemia requiring repeated blood transfusions
B)elevated levels of ferrous iron (Fe2+) in the red cells
C)presence of Heinz bodies on Wright-stained blood film
D)elevated methemoglobin

Question 7

All of the following improve the clinical outcome of sickle cell anemia (Hb SS)except which of the following?

A)aggressive prevention and treatment of infection
B)presence of Hb F
C)transfusions during crises
D)keeping the oxygen saturation low

Question 8

Heinz bodies are found when hemoglobin

A)precipitates.
B)has higher oxygen affinity.
C)concentration is decreased.
D)forms crystals.

Question 9

Which of the following hemoglobinopathies is most common?

A)sickle cell diseases
B)Hb E disorders
C)Hb C disorders
D)unstable hemoglobins

Question 10

Which of the following would be an unusual finding in the blood film of an adult with sickle cell disease crisis?

A)Heinz bodies
B)target cells
C)Howell-Holly bodies
D)leukocytosis

Question 11

Sickle cell disease is found in individuals descended from ancestors from all of the following places except

A)Africa
B)Middle East
C)the Mediterranean
D)Scandinavia

Question 12

What is the most likely causative association between malaria and sickle cell trait?

A)Sickle gene makes people more prone to malaria infection.
B)Sickle gene prevents Plasmodium ovale infection.
C)They are both found in Asia.
D)Sickle gene offers some protection against malaria.

Question 13

A patient has 45% Hb S,55% Hb A,and a positive tube solubility.Which of the following would likely be found?

A)normal blood film and no disease
B)target cells on the blood film and no disease
C)normal blood film and severe disease
D)sickle cells on the blood film and severe disease

Question 14

The qualitative hemoglobinopathies cause disease by producing hemoglobin chains that are

A)too long.
B)produced in inadequate amounts.
C)structurally altered.
D)missing.

Question 15

Moderate to marked target cells are found on a blood film.Which of the following can most likely be eliminated?

A)Hb C disease
B)hereditary spherocytosis
C)Hb E disease
D)sickle cell disease

Question 16

Select the best test to confirm the diagnosis of the patient in Question 9.

A)mean cell volume (MCV)
B)osmotic fragility
C)hemoglobin electrophoresis
D)presence of sickle cells

Question 17

What is the correct relationship between red cells' affinity for oxygen and red cell production?

A)When affinity is low, more oxygen is released and the body compensates by making red cells larger.
B)When affinity is low, less oxygen is released and the body compensates by increasing erythropoietin and making more red cells.
C)When affinity is high, less oxygen is released and the body compensates by increasing erythropoietin and making more red cells.
D)When affinity is high, more oxygen is released and fewer red cells are needed.

Question 18

A patient has two bands on alkaline hemoglobin electrophoresis.One lines up with Hb A and the other is in the S position.Select the best course of action.

A)Report as normal.
B)Report as sickle trait.
C)Report as sickle disease.
D)Confirm sickle gene with tube solubility test.

Question 19

What is a point mutation?

A)mutation of the stop codon
B)replacement of one nucleotide in the normal gene with a different nucleotide
C)addition of one nucleotide in the normal gene
D)deletion of one nucleotide in the normal gene

Question 20

Which of the following would be an unexpected finding for patients with Hb SC disease or S/B⁰⁻ thalassemia?

A)target cells
B)shortened red cell survival
C)normal tube solubility test
D)mild to moderate clinical features

Question 21

An adult female patient from Southeast Asia has no anemia,but her complete blood count (CBC)shows an MCV of 68 fL and marked target cells are observed on her blood film.Cellulose acetate alkaline electrophoresis shows two large bands: approximately 55% migrating with Hb A and 40% migrating with Hb C.What is the patient's most likely genotype?

A)Hb A and Hb C
B)Hb A and Hb E
C)Hb C and Hb E
D)homozygous Hb E