In CKD, iron deficiency is indicated by TSAT below 20% and ferritin below 200.

• A. False
• B. TSAT above 30% and ferritin above 300
• C. True
• D. TSAT below 10% but ferritin above 500

Answer: (C)

In CKD, iron status is interpreted using transferrin saturation (TSAT) and ferritin. TSAT reflects how much iron is available for erythropoiesis; a value below 20% means there isn’t enough circulating iron for making red blood cells. Ferritin represents stored iron in the body; a ferritin level below 200 ng/mL indicates depleted iron stores. When both measurements show low values, it points to iron deficiency. That combination is the standard indicator used in many CKD guidelines, so the statement is true.

Keep in mind ferritin can rise with inflammation, which can mask deficiency. In such cases, iron deficiency may still exist if TSAT is low, even if ferritin is higher, highlighting the difference between absolute iron deficiency and functional iron deficiency.