Yes, You Are Iron Deficient
With a ferritin of 27 ng/mL (well below 100 ng/mL), you meet the criteria for iron deficiency in CKD stage 2, despite your TSAT being slightly above 20% at 24%. 1
Why Your Ferritin Matters More Here
The NKF-K/DOQI guidelines explicitly state that iron deficiency is present when either TSAT ≤20% or ferritin ≤100 ng/mL in CKD patients. 1 You don't need both values to be low to qualify as iron deficient—meeting one criterion is sufficient. 1
- Your ferritin of 27 ng/mL is severely depleted, indicating minimal iron stores in your liver, spleen, and bone marrow. 1
- While your TSAT of 24% suggests some iron is currently available for red blood cell production, this doesn't negate the fact that your storage iron is critically low. 1
- The guidelines emphasize that "the probability that iron deficiency is present increases as the values of these measures decrease," and a ferritin of 27 ng/mL is far below the 100 ng/mL threshold. 1
Understanding the Dual Criteria
The guidelines use both TSAT and ferritin because they measure different aspects of iron status:
- TSAT reflects immediately available iron for erythropoiesis (red blood cell production). 1
- Ferritin reflects storage iron that can be mobilized when needed. 1
- Many CKD patients can have functional iron deficiency even with TSAT >20%, meaning they still benefit from iron supplementation despite seemingly adequate circulating iron. 1
Clinical Implications for You
You should receive iron supplementation to maintain ferritin >100 ng/mL and TSAT >20%. 1
- For CKD stage 2 (non-dialysis), oral iron supplementation is typically the first-line approach, though IV iron may be considered if oral iron is ineffective or poorly tolerated. 2, 3
- Your depleted ferritin stores put you at risk for worsening anemia as your CKD progresses, particularly if you eventually require erythropoiesis-stimulating agents (ESAs). 2, 4
- Low iron stores are associated with worse physical health-related quality of life in CKD patients, independent of hemoglobin levels. 5
Important Caveats
- Ferritin is an acute phase reactant and can be falsely elevated during inflammation or infection, but this doesn't apply to your situation with a low value. 1
- The goal of iron therapy is to improve erythropoiesis and prevent anemia, not just to achieve specific laboratory targets. 1
- Monitor your iron parameters every 2-3 months initially to ensure adequate repletion. 1