MLT GlobeHematology: RBC indices & anemias – page 3
138 Hematology MCQs on RBC indices & anemias with answers and explanations.
Serum iron is 45 µg/dL (8 µmol/L) and TIBC is 450 µg/dL (80 µmol/L). What is the transferrin saturation?
Transferrin saturation = serum iron ÷ TIBC × 100 = 45/450 × 100 = 10%. A value below about 16–20% suggests iron-deficient erythropoiesis.
According to WHO, anemia in a non-pregnant adult woman is defined as a hemoglobin below:
WHO thresholds are <130 g/L for adult men, <120 g/L for non-pregnant women and <110 g/L for pregnant women.
A 24-year-old woman with heavy menstrual periods reports a strong craving to chew ice. This symptom is most typical of:
Pica, especially pagophagia (ice craving), is a classic symptom of iron deficiency and often improves quickly with iron. B12 and folate deficiency do not typically cause pica.
A woman has long-standing microcytic anemia, spoon-shaped nails and difficulty swallowing due to an esophageal web. This combination is known as:
Plummer-Vinson (Paterson-Kelly) syndrome is iron deficiency with koilonychia and a post-cricoid web. Imerslund-Gräsbeck syndrome is inherited selective vitamin B12 malabsorption.
If dietary intake stops completely, body stores usually last about:
The liver holds several milligrams of B12, enough for years, whereas folate stores last only a few months. So folate deficiency develops much faster than dietary B12 deficiency.
A patient had most of the terminal ileum removed for Crohn disease. Loss of this segment directly impairs absorption of:
The B12–intrinsic factor complex is absorbed by cubam receptors in the terminal ileum. Iron is absorbed mainly in the duodenum and folate in the proximal jejunum.
A patient on long-term treatment has MCV 112 fL with normal B12 and folate. Which drug most likely explains this by directly inhibiting DNA synthesis?
Hydroxyurea inhibits ribonucleotide reductase, slowing DNA synthesis and causing macrocytosis; MCV rise is even used to check adherence. The other drugs do not cause macrocytosis.
A patient with fatigue, cold intolerance and weight gain has MCV 103 fL, no hypersegmented neutrophils and normal B12 and folate. Which test is most useful next?
Hypothyroidism is a common cause of non-megaloblastic macrocytosis, and the symptoms support it. Ferritin, HPLC and G6PD address microcytic or hemolytic anemias.
Compared with a healthy adult, the red cells of a healthy term newborn have:
Newborn red cells are macrocytic, with MCV often above 100 fL, and Hb is higher than in adults. MCV falls to childhood levels over the first months.
The fall in hemoglobin concentration seen in normal pregnancy is mainly caused by:
Plasma volume rises by about 40–50% while red cell mass rises less, diluting the Hb. Erythropoietin actually increases in pregnancy.
Serum iron should ideally be collected in the morning after an overnight fast because serum iron:
Serum iron shows diurnal variation (usually higher in the morning) and rises after meals or supplements, so fasting morning samples give comparable results.
Dietary non-heme iron is absorbed mainly in the:
Non-heme iron is reduced to Fe2+ and taken up by DMT1 on duodenal enterocytes, then exported by ferroportin. The terminal ileum absorbs vitamin B12.
A rural farm worker who walks barefoot has chronic microcytic hypochromic anemia and eosinophilia. The most likely parasitic cause is:
Hookworm larvae enter through skin, and adult worms cause chronic intestinal blood loss leading to iron deficiency, often with eosinophilia. Diphyllobothrium causes B12 deficiency, not iron deficiency.
Which hemoglobin value lies within the usual reference interval for a healthy adult man?
Adult male hemoglobin is roughly 13–17 g/dL, so 15.0 g/dL is well inside the range. 9.5 and 11.0 g/dL indicate anemia, and 21.0 g/dL suggests polycythemia.
Which plasma protein carries iron from the gut and storage sites to developing red cells in the marrow?
Transferrin is the iron transport protein of plasma and delivers iron to erythroblasts through the transferrin receptor. Ferritin is the storage form, and haptoglobin binds free hemoglobin.
Which dietary factor increases the absorption of non-heme iron?
Ascorbic acid keeps iron in the ferrous (Fe2+) form, which is absorbed more easily. Tannins, phytates and calcium all reduce non-heme iron absorption.
Intrinsic factor, needed for vitamin B12 absorption, is secreted by which cells?
Parietal cells of the stomach secrete both hydrochloric acid and intrinsic factor. Chief cells secrete pepsinogen, and the ileum is where the B12–intrinsic factor complex is absorbed.
Hereditary hemochromatosis, a common inherited cause of iron overload, is most often due to mutation of which gene?
Most cases of hereditary hemochromatosis are caused by the HFE C282Y mutation, which leads to excess iron absorption. JAK2 relates to myeloproliferative neoplasms and HBB to beta-globin disorders.
A person who has followed a strict vegan diet for many years is at greatest risk of deficiency of which vitamin?
Vitamin B12 comes almost only from animal foods, so long-term strict vegans can become deficient. Folate, vitamin C and vitamin K are plentiful in plant foods.
Dietary folate is absorbed mainly in which part of the gut?
Folate is absorbed in the proximal small intestine (duodenum and jejunum). The terminal ileum is the site of vitamin B12 absorption.