Question

All are increased in Iron Deficiency Anemia (IDA) except?

• A. TIBC
• B. Soluble transferrin receptor
• C. Transferrin saturation
• D. Erythropoietin

Hint:

Consider which iron study parameter falls when serum iron is low and TIBC is high.

Answer 1

The Correct Option is C

In Iron Deficiency Anemia (IDA), iron stores are depleted, causing characteristic changes in iron-related laboratory parameters.

Parameters and their changes in IDA:
- $TIBC$: Increased - liver upregulates transferrin production to maximise iron capture
- $Soluble\ transferrin\ receptor\ (sTfR)$: Increased - elevated specifically in tissue iron deficiency, useful to distinguish IDA from anaemia of chronic disease
- $Transferrin\ saturation$: Decreased - calculated as $\frac{Serum\ Iron}{TIBC} \times 100$; both numerator falls and denominator rises, so saturation drops significantly
- $Erythropoietin$: Increased - renal sensor detects hypoxia and releases more EPO

Memory aid: In IDA, think "High TIBC, High sTfR, High EPO, Low everything else (iron, ferritin, transferrin saturation, MCV, MCH)."

\[\boxed{\text{Transferrin saturation (Decreased, not increased)}}\]