Antenatal Visits and Investigations MCQ — NEET PG Practice Question | NEETPGAI
Antenatal Visits and Investigations
hard
baby OBG
A 28-year-old primigravida at 32 weeks of gestation is screened for anemia. Her hemoglobin is 9.5 g/dL. Which laboratory finding best distinguishes iron deficiency anemia from anemia of chronic disease in pregnancy?
A. Mean corpuscular volume (MCV) <80 fL
B. Serum iron level <60 μg/dL
C. Serum ferritin level <30 ng/mL
D. Total iron-binding capacity (TIBC) >360 μg/dL
Explanation
Distinguishing Iron Deficiency Anemia from Anemia of Chronic Disease in Pregnancy
Core Discriminator
Key Point
Serum ferritin is the single best laboratory test to distinguish iron deficiency anemia (IDA) from anemia of chronic disease (ACD). A serum ferritin <30 ng/mL is highly specific for depleted iron stores and is diagnostic of IDA.
High-YieldNEET PG
In IDA, ferritin is low (<30 ng/mL) because ferritin directly reflects iron stores. In ACD, ferritin is normal or elevated (>100 ng/mL) because ferritin is an acute-phase reactant that rises with chronic inflammation — even when functional iron availability is reduced.
Comparison Table
Table
Parameter
Iron Deficiency Anemia
Anemia of Chronic Disease
Serum ferritin
↓ (<30 ng/mL) — best discriminator
↑ or normal (>100 ng/mL)
TIBC
↑ (>360 μg/dL)
↓ or normal (<300 μg/dL)
Serum iron
↓ (<60 μg/dL)
↓ (<60 μg/dL) — not discriminating
MCV
↓ (<80 fL)
Normal or mildly ↓ — not discriminating
Transferrin saturation
↓ (<16%)
↓ (<16%) — not discriminating
Why Ferritin is Superior to TIBC
1.
Ferritin directly reflects iron stores: A low ferritin is virtually pathognomonic of IDA; no other condition lowers ferritin.
2.
TIBC is elevated in IDA (body upregulates transferrin to maximize absorption) and low in ACD (hepcidin suppresses transferrin production) — this is a valid finding, but ferritin is more sensitive and specific as a single discriminator per standard references (Harrison's, WHO guidelines).
3.
Serum iron and MCV are reduced in BOTH conditions and therefore cannot reliably distinguish between them.
4.
Pregnancy caveat: Ferritin may be mildly elevated in concurrent infection/inflammation, but a value <30 ng/mL still reliably identifies IDA. Values <12 ng/mL are unequivocally diagnostic.
Clinical Pearl
According to Harrison's Principles of Internal Medicine and WHO antenatal guidelines, serum ferritin is the recommended first-line test to confirm iron deficiency. TIBC adds confirmatory value but is not the primary discriminator. In resource-limited settings (including routine Indian antenatal care), ferritin is the preferred and most cost-effective single test.
Mnemonic
Ferritin = Iron Store Meter — Low ferritin = empty stores = IDA; High/Normal ferritin = stores intact = ACD (iron trapped, not depleted).
Reference: Harrison's Principles of Internal Medicine, 21st ed., Chapter on Anemias; WHO Guidelines for Antenatal Care.
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