CHAPTER 11: IRON KINETICS AND LABORATORY ASSESSMENT

Question 1

(1) Iron is transported in plasma via:

a. Hemosiderin
b. Ferritin
c. Transferrin
d. Hemoglobin

Answer 1

c. Transferrin

Question 2

(2) What is the major metabolically available storage form of iron in the body?

a. Hemosiderin
b. Ferritin
c. Transferrin
d. Hemoglobin

Answer 2

b. Ferritin

Question 3

(3) The total iron-binding capacity (TIBC) of the serum is an indirect measure of which iron-related protein?

a. Hemosiderin
b. Ferritin
c. Transferrin
d. Hemoglobin

Answer 3

c. Transferrin

Question 4

(4) For a patient with classic iron study values that are equivocal for iron deficiency, which of the following tests would be most helpful in determining whether iron deficiency is present or not?

a. Zinc protoporphyrin
b. Peripheral blood sideroblast assessment
c. Soluble transferrin receptor
d. Mean cell hemoglobin

Answer 4

c. Soluble transferrin receptor

Question 5

(5) What membrane-associated protein in enterocytes transports iron from the intestinal lumen into the enterocyte?

a. Transferrin
b. Ferroportin
c. DMT1
d. Ferrochelatase

Answer 5

c. DMT1

Question 6

(6) Iron is transported out of macrophages, hepatocytes, and enterocytes by what membrane protein?

a. Transferrin
b. Ferroportin
c. DMT1
d. Ferrochelatase

Answer 6

b. Ferroportin

Question 7

(7) Below are several of the many steps in the process from
absorption and transport of iron to incorporation into heme. Place them in proper order.

i. Transferrin picks up ferric iron.
ii. Iron is transferred to the mitochondria.
iii. DMT1 transports ferrous iron into the enterocyte.
iv. Ferroportin transports iron from enterocyte to plasma.
v. The transferrin receptor transports iron into the cell.

a. v, iv, i, ii, iii
b. iii, ii, iv, i, v
c. ii, i, v, iii, iv
d. iii, iv, i, v, ii

Answer 7

d. iii, iv, i, v, ii

Question 8

(8) What is the fate of the transferrin receptor when it has completed its role in the delivery of iron to a cell?

a. It is recycled to the plasma membrane and released into the plasma.
b. It is recycled to the plasma membrane, where it can bind its ligand again.
c. It is catabolized and the amino acids are returned to the metabolic pool.
d. It is retained in the endosome for the life span of the cell.

Answer 8

b. It is recycled to the plasma membrane, where it can bind its ligand again.

Question 9

(9) The transfer of iron from the enterocyte into the plasma is REGULATED by:

a. Transferrin
b. Ferroportin
c. Hephaestin
d. Hepcidin

Answer 9

d. Hepcidin

Question 10

(10) What is the percent transferrin saturation for a patient with total serum iron of 63 ug/dL and TIBC of 420 ug/dL ?

a. 6.7%
b. 12%
c. 15%
d. 80%

Answer 10

c. 15%

Question 11

Referring to the figure shown in the link below, into which quadrant of a Thomas plot would a patient’s results fall with the following test results:

Soluble transferrin receptor: increased above reference interval
Ferritin: decreased below reference interval
Hemoglobin content of reticulocytes: within the reference interval

https://drive.google.com/file/d/1g65q93zfHYc6D3DJHRKfWSdIu_tbpaAt/view

a. Normal iron status
b. Latent iron deficiency
c. Functional iron deficiency
d. Iron deficiency

Answer 11

b. Latent iron deficiency

Question 12

(12) A physician is concerned that a patient is developing iron deficiency from chronic intestinal bleeding due to aspirin use for rheumatoid arthritis. The iron studies on the patient show the following results:

https://drive.google.com/file/d/1-l034mHC_UO6Y-_wgybnazj1ND06fC92/view

How would these results be interpreted?

a. Latent iron deficiency
b. Functional iron deficiency
c. Iron deficiency
d. Equivocal for iron deficiency

Answer 12

d. Equivocal for iron deficiency