Iron deficiency anemia US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Iron deficiency anemia. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Iron deficiency anemia US Medical PG Question 1: A 42-year-old man with a history of tuberculosis presents to your office complaining of fatigue for two months. Serum laboratory studies reveal the following: WBC 7,000 cells/mm^3, Hb 9.0 g/dL, Hct 25%, MCV 88 fL, Platelet 450,000 cells/mm^3, Vitamin B12 500 pg/mL (200-800), and Folic acid 17 ng/mL (2.5-20). Which of the following is the most appropriate next step in the management of anemia in this patient?
- A. Iron studies (Correct Answer)
- B. Bone marrow biopsy
- C. Observation
- D. Colonoscopy
- E. Erythropoietin administration
Iron deficiency anemia Explanation: ***Iron studies***
- The patient has **normocytic anemia** (MCV 88 fL) and a history of **tuberculosis**, which is a chronic inflammatory condition often associated with **anemia of chronic disease (ACD)**.
- **Iron studies** are critical to differentiate between **ACD** (typically high ferritin, low transferrin saturation) and iron deficiency anemia, which can coexist.
*Bone marrow biopsy*
- A **bone marrow biopsy** is an invasive procedure and is typically reserved for cases of unexplained severe anemia, pancytopenia, or suspicion of primary bone marrow disorders that are not suggested by the current findings.
- The current blood counts do not indicate an urgent need for bone marrow evaluation, as the **anemia is mild to moderate**, and other cell lines are normal (WBC) or elevated (platelets).
*Erythropoietin administration*
- **Erythropoietin administration** is used in specific anemias, such as **anemia of chronic kidney disease** or certain types of myelodysplastic syndromes.
- It is not the initial step for diagnosing and managing anemia in a patient with a chronic inflammatory condition like tuberculosis without first assessing iron status or ruling out other treatable causes.
*Observation*
- **Observation** is inappropriate given the patient's symptomatic anemia (fatigue) and the identified abnormalities (Hb 9.0 g/dL).
- Anemia warrants investigation to identify its cause and provide appropriate treatment, especially in the context of a chronic illness like tuberculosis.
*Colonoscopy*
- A **colonoscopy** is indicated if there is suspicion of **gastrointestinal blood loss**, which typically presents with **microcytic anemia** (low MCV) due to chronic iron deficiency.
- This patient has **normocytic anemia**, and there are no symptoms suggestive of GI bleeding, making colonoscopy not the most appropriate first step.
Iron deficiency anemia US Medical PG Question 2: A 55-year-old woman comes to the physician because of a 6-month history of worsening shortness of breath on exertion and fatigue. She has type 1 diabetes mellitus, hypertension, hypercholesterolemia, and chronic kidney disease. Her mother was diagnosed with colon cancer at the age of 65 years. Her blood pressure is 145/92 mm Hg. Examination shows conjunctival pallor. Laboratory studies show:
Hemoglobin 9.2 g/dL
Mean corpuscular volume 88 μm3
Reticulocyte count 0.6 %
Serum
Ferritin 145 ng/mL
Creatinine 3.1 mg/dL
Calcium 8.8 mg/dL
A fecal occult blood test is pending. Which of the following is the most likely underlying cause of this patient's symptoms?
- A. Decreased erythropoietin production (Correct Answer)
- B. Chronic occult blood loss
- C. Deficient vitamin B12 intake
- D. Hematopoietic progenitor cell mutation
- E. Autoantibodies against the thyroid gland
Iron deficiency anemia Explanation: ***Decreased erythropoietin production***
- The patient's **chronic kidney disease** (CKD) with a creatinine of 3.1 mg/dL is the most likely cause of her **normocytic anemia** and low reticulocyte count. The kidneys produce **erythropoietin (EPO)**, and in CKD, this production is impaired, leading to insufficient stimulation of red blood cell production.
- Her **normocytic anemia** (MCV 88 μm3) and **low reticulocyte count** (0.6%) indicate an underproduction of red blood cells, rather than a problem with cell size or destruction, which is characteristic of anemia of chronic kidney disease.
*Chronic occult blood loss*
- While chronic blood loss can cause anemia, it typically leads to **iron deficiency anemia**, characterized by **microcytic anemia** (low MCV) and **low ferritin** levels. This patient has a normocytic MCV and a normal ferritin level.
- The patient's presentation with **normocytic anemia** and **normal ferritin** makes chronic occult blood loss less likely as the primary cause, even though a fecal occult blood test is pending.
*Deficient vitamin B12 intake*
- Vitamin B12 deficiency causes **macrocytic (megaloblastic) anemia**, characterized by an **elevated MCV** (Mean Corpuscular Volume). This patient has a normocytic MCV (88 μm3).
- Symptoms of vitamin B12 deficiency can also include neurological manifestations, which are not mentioned in this patient's presentation.
*Hematopoietic progenitor cell mutation*
- A **hematopoietic progenitor cell mutation** could lead to conditions like myelodysplastic syndromes or aplastic anemia, which often present with pancytopenia or characteristic abnormal blood cell morphologies.
- The isolated normocytic anemia with a clear underlying cause (CKD) makes a primary bone marrow disorder less likely, especially with a normal ferritin and MCV.
*Autoantibodies against the thyroid gland*
- **Hypothyroidism** due to autoantibodies can cause fatigue, but it typically causes **anemia that is normocytic or macrocytic**, and often linked to iron deficiency or pernicious anemia, or less commonly, directly due to decreased erythropoiesis.
- While fatigue can be a symptom, it would not explain the specific laboratory findings of **normocytic anemia with low reticulocytes in a patient with significant renal failure** as well as decreased erythropoietin production does.
Iron deficiency anemia US Medical PG Question 3: A 57-year-old woman comes to the physician because of a 3-month history of easy fatigability and dyspnea on exertion. Menopause occurred 5 years ago. Her pulse is 105/min and blood pressure is 100/70 mm Hg. Physical examination shows pallor of the nail beds and conjunctivae. A peripheral blood smear shows small, pale red blood cells. Further evaluation is most likely to show which of the following findings?
- A. Increased concentration of HbA2
- B. Decreased serum haptoglobin concentration
- C. Positive stool guaiac test (Correct Answer)
- D. Dry bone marrow tap
- E. Increased serum methylmalonic acid concentration
Iron deficiency anemia Explanation: ***Positive stool guaiac test***
* The patient's symptoms of **fatigability**, **dyspnea on exertion**, and signs like **pallor**, along with a peripheral blood smear showing **small, pale red blood cells** (**microcytic hypochromic anemia**), are highly indicative of **iron deficiency anemia**.
* In a 57-year-old postmenopausal woman, the most common cause of **iron deficiency anemia** is **chronic blood loss from the gastrointestinal (GI) tract**, which would be detected by a **positive stool guaiac test**.
*Increased concentration of HbA2*
* An increased concentration of **HbA2** is characteristic of **beta-thalassemia minor**, a genetic disorder, which presents as microcytic anemia, but the clinical context and age make iron deficiency due to blood loss more likely in this patient.
* While both can cause microcytic anemia, the patient's acute presentation of symptoms and postmenopausal status strongly point to an acquired cause like chronic blood loss rather than a lifelong genetic condition.
*Decreased serum haptoglobin concentration*
* **Decreased serum haptoglobin concentration** is a marker of **hemolytic anemia**, where red blood cells are prematurely destroyed, leading to the release of free hemoglobin that binds to haptoglobin.
* The patient's peripheral smear finding of **small, pale red blood cells** (microcytic hypochromic) is inconsistent with hemolysis as the primary cause; hemolytic anemias often present with normocytic or macrocytic red blood cells.
*Dry bone marrow tap*
* A **dry bone marrow tap** is typically associated with **myelofibrosis** or sometimes **hairy cell leukemia** or severe aplastic anemia, where the bone marrow is fibrotic or hypocellular and cannot be aspirated.
* Iron deficiency anemia, while causing anemia, does not typically lead to a dry bone marrow tap; the marrow would usually be hypercellular with erythroid hyperplasia, reflecting the body's attempt to compensate for the anemia.
*Increased serum methylmalonic acid concentration*
* An **increased serum methylmalonic acid concentration** is a specific marker for **vitamin B12 deficiency**, which causes **megaloblastic (macrocytic) anemia**.
* The patient's peripheral blood smear findings of **small, pale red blood cells** (microcytic hypochromic) are inconsistent with **vitamin B12 deficiency**, which leads to **large red blood cells**.
Iron deficiency anemia US Medical PG Question 4: A 4-year-old boy is brought to the physician for the evaluation of fatigue since he returned from visiting family in South Africa one week ago. The day after he returned, he had fever, chills, and diffuse joint pain for 3 days. His symptoms improved with acetaminophen. He was born at term and has been healthy. His immunizations are up-to-date. His temperature is 37.6°C (99.68°F), pulse is 100/min, and blood pressure is 100/60 mm Hg. Examination shows conjunctival pallor. The remainder of the examination shows no abnormalities. Laboratory studies show:
Hemoglobin 10.8 g/dL
Mean corpuscular volume 68 μm3
Red cell distribution width 14% (N = 13%–15%)
Hemoglobin A2 6% (N < 3.5%)
A peripheral smear shows microcytic, hypochromic erythrocytes, some of which have a darkly stained center and peripheral rim, separated by a pale ring. Which of the following is the most appropriate next step in the management of this patient?
- A. Oral pyridoxine
- B. Iron supplementation
- C. Reassurance (Correct Answer)
- D. Folic acid therapy
- E. Oral succimer
Iron deficiency anemia Explanation: ***Reassurance***
- The patient's presentation with **microcytic anemia**, elevated **Hemoglobin A2 (6%)**, and **target cells** on peripheral smear is highly suggestive of **beta-thalassemia trait** (minor). This genetic condition is more common in individuals with Mediterranean, African, Middle Eastern, or South Asian ancestry.
- Beta-thalassemia trait is a **benign condition** that does not typically require specific medical intervention. The mild anemia does not usually cause significant symptoms or complications, and patients can live normal lives without treatment.
- The elevated HbA2 is the key diagnostic finding that distinguishes thalassemia trait from iron deficiency anemia.
*Oral pyridoxine*
- **Pyridoxine (Vitamin B6)** supplementation is indicated for **sideroblastic anemia**, which can also cause microcytic anemia.
- However, sideroblastic anemia typically presents with **ring sideroblasts** in the bone marrow and does not have the characteristic elevated HbA2 seen in beta-thalassemia trait.
*Iron supplementation*
- **Iron deficiency anemia** is a common cause of microcytic hypochromic anemia, but it would present with **low ferritin** and **low or normal HbA2** (not elevated).
- In this case, iron supplementation would not be appropriate and could potentially be harmful due to the risk of **iron overload** in thalassemia syndromes, even in the trait form.
- The elevated HbA2 and normal RDW help distinguish thalassemia trait from iron deficiency.
*Folic acid therapy*
- **Folic acid** is primarily used in the management of **macrocytic anemias** or in conditions with high red blood cell turnover, such as **hemolytic anemias** or major thalassemia syndromes requiring chronic transfusions.
- It is not indicated for beta-thalassemia trait, which is a microcytic anemia with normal red blood cell turnover and no significant hemolysis.
*Oral succimer*
- **Succimer** is a chelating agent used to treat **lead poisoning**, which can cause microcytic anemia with basophilic stippling.
- There are no clinical or laboratory findings in this patient (e.g., **basophilic stippling**, developmental delays, neurological symptoms, abdominal pain) to suggest lead poisoning.
Iron deficiency anemia US Medical PG Question 5: A 55-year-old woman presents with fatigue. She says her symptoms are present throughout the day and gradually started 4 months ago. Her past medical history is significant for rheumatoid arthritis–treated with methotrexate, and diabetes mellitus type 2–treated with metformin. The patient is afebrile, and her vital signs are within normal limits. A physical examination reveals pallor of the mucous membranes. Initial laboratory tests show hemoglobin of 7.9 g/dL, hematocrit of 22%, and mean corpuscular volume of 79 fL. Which of the following is the best next diagnostic step in this patient?
- A. Serum ferritin level and total iron-binding capacity (TIBC)
- B. Serum ferritin and serum iron levels
- C. Serum ferritin and soluble transferrin receptor levels (Correct Answer)
- D. Serum iron level
- E. Serum ferritin level
Iron deficiency anemia Explanation: ***Serum ferritin and soluble transferrin receptor levels***
- This patient has **anemia** (hemoglobin 7.9 g/dL) with **microcytic** (MCV 79 fL) and **hypochromic** features, suggesting either **iron deficiency anemia (IDA)** or **anemia of chronic disease (ACD)**. Given her history of **rheumatoid arthritis**, ACD is highly likely, but co-existing IDA needs to be excluded.
- **Serum ferritin** is an acute-phase reactant, so it can be elevated in ACD masking a co-existing iron deficiency. **Soluble transferrin receptor (sTfR)** levels are increased in IDA and remain normal or only mildly elevated in ACD, making it a reliable marker to differentiate between these two conditions when ferritin is uninterpretable due to inflammation.
*Serum ferritin level and total iron-binding capacity (TIBC)*
- While these tests are useful for diagnosing iron deficiency, **ferritin** can be falsely elevated in the context of inflammation (e.g., from **rheumatoid arthritis**), making it unreliable for diagnosing IDA in this patient.
- **TIBC** can be decreased in ACD, complicating its interpretation for IDA when inflammation is present.
*Serum ferritin and serum iron levels*
- As mentioned, **serum ferritin** is an acute-phase reactant and may be elevated due to **rheumatoid arthritis**, potentially masking **iron deficiency**.
- **Serum iron levels** fluctuate significantly and are not a reliable standalone indicator for iron status, especially in the context of chronic disease.
*Serum iron level*
- **Serum iron levels** are highly variable and not sufficient for diagnosing **iron deficiency** or differentiating it from **anemia of chronic disease**.
- A low serum iron can be seen in both IDA and ACD but does not provide definitive diagnostic information on its own.
*Serum ferritin level*
- Measuring **serum ferritin** alone is insufficient because it is an **acute-phase reactant** that can be elevated due to the patient's **rheumatoid arthritis**, even if she has co-existing **iron deficiency anemia**.
- A normal or high ferritin level in this context does not rule out **iron deficiency**.
Iron deficiency anemia US Medical PG Question 6: A 24-year-old Asian woman comes to the office complaining of fatigue. She states that for weeks she has noticed a decrease in her energy. She is a spin instructor, and she has been unable to teach. She said that when she was bringing groceries up the stairs yesterday she experienced some breathlessness and had to rest after ascending 1 flight. She denies chest pain, palpitations, or dyspnea at rest. She has occasional constipation. She recently became vegan 3 months ago following a yoga retreat abroad. The patient has no significant medical history and takes no medications. She was adopted, and her family history is non-contributory. She has never been pregnant. Her last menstrual period was 3 days ago, and her periods are regular. She is sexually active with her boyfriend of 2 years and uses condoms consistently. She drinks a glass of red wine each evening with dinner. She denies tobacco use or other recreational drug use. Her temperature is 99°F (37.2°C), blood pressure is 104/74 mmHg and pulse is 95/min. Oxygen saturation is 98% while breathing ambient air. On physical examination, bilateral conjunctiva are pale. Her capillary refill is 3 seconds. A complete blood count is drawn, as shown below:
Hemoglobin: 10 g/dL
Hematocrit: 32%
Leukocyte count: 10,000/mm^3 with normal differential
Platelet count: 200,000/mm^3
A peripheral smear shows hypochromic red blood cells and poikilocytosis. A hemoglobin electrophoresis reveals a minor reduction in hemoglobin A2. Which of the following is most likely to be seen on the patient’s iron studies?
- A. Decreased serum iron and increased TIBC (Correct Answer)
- B. Normal serum iron and normal TIBC
- C. Increased serum iron and decreased TIBC
- D. Increased serum ferritin and increased iron saturation
- E. Decreased serum iron and decreased TIBC
Iron deficiency anemia Explanation: ***Decreased serum iron and increased TIBC***
- The patient's symptoms (fatigue, breathlessness, pale conjunctiva, prolonged capillary refill) and lab results (hemoglobin 10 g/dL, hematocrit 32%, hypochromic red blood cells, poikilocytosis) are highly indicative of **iron deficiency anemia (IDA)**.
- The **decreased hemoglobin A2** on electrophoresis further supports IDA, as HbA2 levels are typically reduced in iron deficiency (whereas they are elevated in beta-thalassemia trait).
- In IDA, the body lacks iron, leading to **decreased serum iron** and a compensatory **increased total iron-binding capacity (TIBC)** as the body tries to maximize iron absorption and transport.
*Normal serum iron and normal TIBC*
- This profile is typically seen in individuals without iron metabolic disturbances, which contradicts the patient's clear signs and symptoms of **anemia** and likely iron deficiency.
- Normal iron studies would not explain the **hypochromic microcytic red blood cells** found on the peripheral smear.
*Increased serum iron and decreased TIBC*
- This pattern is characteristic of **iron overload conditions** such as hemochromatosis or sideroblastic anemia, which are inconsistent with the patient's presentation of fatigue and anemia.
- Decreased TIBC indicates the body has sufficient or excess iron and does not need to increase iron binding protein production.
*Decreased serum iron and decreased TIBC*
- This finding is most commonly associated with **anemia of chronic disease (ACD)**, where inflammatory mediators lead to iron sequestration, resulting in both low serum iron and reduced TIBC.
- While the patient has some signs of anemia, her recent switch to a **vegan diet** and the absence of a chronic inflammatory condition make IDA more likely than ACD.
*Increased serum ferritin and increased iron saturation*
- **Increased serum ferritin** would indicate iron overload or inflammation, while **increased iron saturation** suggests there is plenty of iron available for binding.
- These findings are contrary to the classic picture of **iron deficiency anemia**, where ferritin (the storage form of iron) would be low, and iron saturation would be reduced due to insufficient iron.
Iron deficiency anemia US Medical PG Question 7: A 65-year-old man presents to his primary care physician for a yearly checkup. He states he feels he has been in good health other than minor fatigue, which he attributes to aging. The patient has a past medical history of hypertension and is currently taking chlorthalidone. He drinks 1 glass of red wine every night. He has lost 5 pounds since his last appointment 4 months ago. His temperature is 99.2°F (37.3°C), blood pressure is 147/98 mmHg, pulse is 80/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam reveals an obese man in no acute distress. Laboratory values are ordered as seen below.
Hemoglobin: 9 g/dL
Hematocrit: 27%
Mean corpuscular volume: 72 µm^3
Leukocyte count: 6,500/mm^3 with normal differential
Platelet count: 193,000/mm^3
Serum:
Na+: 139 mEq/L
Cl-: 101 mEq/L
K+: 4.3 mEq/L
HCO3-: 25 mEq/L
BUN: 20 mg/dL
Glucose: 99 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 9.0 mg/dL
AST: 32 U/L
ALT: 20 U/L
25-OH vitamin D: 15 ng/mL
Which of the following is the best next step in management?
- A. Counseling for alcohol cessation
- B. Vitamin D supplementation
- C. Colonoscopy (Correct Answer)
- D. Exercise regimen and weight loss
- E. Iron supplementation
Iron deficiency anemia Explanation: ***Colonoscopy***
- The patient presents with **microcytic anemia** (hemoglobin 9 g/dL, MCV 72 µm^3) and **unexplained weight loss** in an elderly male, which is highly suggestive of **gastrointestinal bleeding**, often due to **colorectal cancer**.
- A **colonoscopy** is the definitive diagnostic and therapeutic procedure for evaluating the lower gastrointestinal tract for sources of bleeding and identifying/removing suspicious lesions.
*Counseling for alcohol cessation*
- While chronic alcohol use can contribute to various health issues, including some anemias (e.g., folate deficiency), the patient's presented **microcytic anemia** is not typical for alcohol-related causes.
- The patient's reported alcohol intake of one glass of red wine nightly is generally considered moderate and less likely to be the primary cause of his symptoms and lab findings.
*Vitamin D supplementation*
- The patient has a **low 25-OH vitamin D level (15 ng/mL)**. However, this finding, while important for bone health and overall well-being, does not explain his microcytic anemia or unexplained weight loss.
- Addressing the **anemia and weight loss** takes precedence as these symptoms point to a more urgent, potentially life-threatening condition.
*Exercise regimen and weight loss*
- The patient is obese and has hypertension, for which an **exercise regimen and weight loss** would be beneficial for overall health and blood pressure management.
- However, these interventions **do not address the microcytic anemia and unexplained weight loss**, which are more pressing concerns requiring immediate investigation.
*Iron supplementation*
- The **microcytic anemia** strongly suggests **iron deficiency**, and iron supplementation would eventually be part of treatment.
- However, **iron supplementation** without identifying and treating the underlying cause of iron loss (e.g., gastrointestinal bleeding) would be insufficient and could delay a crucial diagnosis.
Iron deficiency anemia US Medical PG Question 8: A 26-year-old woman presents to the clinic today complaining of weakness and fatigue. She is a vegetarian and often struggles to maintain an adequate intake of non-animal based protein. She currently smokes 1 pack of cigarettes per day, drinks a glass of wine per day, and she currently denies any illicit drug use. Her past medical history is non-contributory. The vital signs include: temperature 36.7°C (98.0°F), blood pressure 126/74 mm Hg, heart rate 87/min, and respiratory rate 16/min. On physical examination, her pulses are bounding, the complexion is pale, the breath sounds are clear, and the heart sounds are normal. The spleen is mildly enlarged. She is at a healthy body mass index (BMI) of 22 kg/m2. The laboratory results indicate: mean corpuscular volume MCV: 71 fL, Hgb: 11.0, total iron-binding capacity (TIBC): 412 mcg/dL, transferrin saturation (TSAT): 11%. What is the most appropriate treatment for this patient?
- A. Lifelong Vitamin B1 supplementation
- B. Obtain a bone-marrow biopsy
- C. Lifelong Vitamin B6 supplementation
- D. Iron replacement for 4–6 months (Correct Answer)
- E. Folic acid supplementation
Iron deficiency anemia Explanation: ***Iron replacement for 4–6 months***
- The patient presents with **microcytic anemia** (MCV 71 fL, Hgb 11.0 g/dL), **low transferrin saturation** (11%), and **high total iron-binding capacity** (TIBC 412 mcg/dL), which are classic findings for **iron deficiency anemia**.
- Given her vegetarian diet, smoking, and symptoms of weakness, fatigue, and **pallor**, iron replacement is the most appropriate and direct treatment to correct her deficiency and replenish stores over several months.
*Lifelong Vitamin B1 supplementation*
- **Vitamin B1 (thiamine) deficiency** causes conditions like **beriberi** or **Wernicke-Korsakoff syndrome**, which present with neurological and cardiovascular symptoms, not microcytic anemia.
- The patient's lab results and symptoms are inconsistent with thiamine deficiency.
*Obtain a bone-marrow biopsy*
- A bone marrow biopsy is typically reserved for cases of **unexplained anemia**, suspected hematologic malignancies, or when other workups are inconclusive.
- The patient's presentation and lab findings clearly point to **iron deficiency anemia**, making a bone marrow biopsy unnecessary as an initial diagnostic step.
*Lifelong Vitamin B6 supplementation*
- **Vitamin B6 (pyridoxine) deficiency** can cause **sideroblastic anemia**, which is also microcytic but is characterized by **increased iron stores** and ring sideroblasts in the bone marrow, quite different from this patient's iron deficiency.
- The patient's lab results, particularly the low TSAT and high TIBC, rule out sideroblastic anemia.
*Folic acid supplementation*
- **Folic acid deficiency** causes **macrocytic anemia** (high MCV), not the microcytic anemia seen in this patient.
- Her MCV of 71 fL suggests microcytic anemia, contradicting a diagnosis of folic acid deficiency.
Iron deficiency anemia US Medical PG Question 9: A 25-year-old woman is being evaluated due to complaint of fatigue and voiding pink urine. The laboratory results are as follows:
Hb 6.7
Red blood cell count 3.0 x 1012/L
Leukocyte count 5,000/mm3
Platelets 170 x 109/L
Reticulocyte count 6%
Hematocrit 32%
The physician thinks that the patient is suffering from an acquired mutation in hematopoietic stem cells, which is confirmed by flow cytometry analysis that revealed these cells are CD 55 and CD 59 negative. However, the physician is interested in knowing the corrected reticulocyte count before starting the patient on eculizumab. What value does the physician find after calculating the corrected reticulocyte count?
- A. 3.1%
- B. 0.4%
- C. 0.1%
- D. 0.6%
- E. 4.6% (Correct Answer)
Iron deficiency anemia Explanation: ***4.6%***
- The corrected reticulocyte count accounts for the degree of anemia by adjusting for the patient's hematocrit compared to normal.
- **Formula: Corrected Retics% = Observed Retics% × (Patient's Hct / Normal Hct)**
- Using normal Hct of 42% for women: 6% × (32/42) = 6% × 0.76 = **4.56% ≈ 4.6%**
- This reflects the actual reticulocyte production capacity adjusted for the anemic state.
*3.1%*
- This value might result from using an incorrect normal hematocrit value in the calculation.
- For example, using 6% × (32/60) would give approximately 3.2%, suggesting use of an inappropriately high reference value.
*0.4%*
- This value likely results from applying the **Reticulocyte Production Index (RPI)** formula, which includes a maturation factor correction: 6% × (32/42) × (1/2.5) = 1.82%, then with further error.
- Such a low value from formula misapplication does not represent the standard corrected reticulocyte count requested.
*0.1%*
- This extremely low value would indicate **severe calculation error** or bone marrow failure, which contradicts the observed 6% reticulocyte count.
- In PNH with hemolysis, reticulocyte production is typically increased, making this value implausible.
*0.6%*
- This incorrect value could result from mathematical errors in applying correction factors or using the wrong hematocrit values in the formula.
- The standard corrected reticulocyte formula would not yield this value with the given parameters.
Iron deficiency anemia US Medical PG Question 10: A 72-year-old woman comes to the physician because of a 1-month history of progressive fatigue and shortness of breath. Physical examination shows generalized pallor. Laboratory studies show:
Hemoglobin 5.8 g/dL
Hematocrit 17%
Mean corpuscular volume 86 μm3
Leukocyte count 6,200/mm3 with a normal differential
Platelet count 240,000/mm3
A bone marrow aspirate shows an absence of erythroid precursor cells. This patient’s condition is most likely associated with which of the following?
- A. Cold agglutinins
- B. Thymic tumor (Correct Answer)
- C. HbF persistence
- D. Parvovirus B19 infection
- E. Lead poisoning
Iron deficiency anemia Explanation: ***Thymic tumor***
- The patient's **normocytic anemia** (Hb 5.8 g/dL, Hct 17%, MCV 86 μm3) and the **absence of erythroid precursor cells** in the bone marrow aspirate are characteristic findings of **pure red cell aplasia (PRCA)**.
- **Pure red cell aplasia (PRCA)** in adults is frequently associated with an underlying **thymoma**, with up to 50% of adult PRCA cases linked to this condition.
*Cold agglutinins*
- Cold agglutinins are characteristic of **cold agglutinin disease**, an **autoimmune hemolytic anemia**.
- This condition typically presents with signs of **hemolysis** (e.g., elevated reticulocytes, bilirubin, LDH) and would not show an **absence of erythroid precursor cells** in the bone marrow.
*HbF persistence*
- **Hereditary persistence of fetal hemoglobin (HPFH)** is a benign condition where **HbF** production continues into adulthood.
- It is not associated with anemia or bone marrow aplasia and usually results in normal hematological parameters, except for elevated HbF.
*Parvovirus B19 infection*
- **Parvovirus B19** can cause transient **aplastic crisis** by infecting and destroying erythroid precursors.
- While it causes PRCA-like features, it is typically an acute self-limiting condition, particularly in immunocompetent individuals, and is less likely to be an ongoing chronic cause in a 72-year-old without other risk factors for chronic infection or immunodeficiency.
*Lead poisoning*
- **Lead poisoning** typically causes a **microcytic hypochromic anemia** with **basophilic stippling** on peripheral blood smear.
- It primarily interferes with **heme synthesis** and would not cause a complete absence of erythroid precursor cells in the bone marrow.
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