From the Guidelines
Yes, it is concerning to have a serum iron of 173 μg/dL with a ferritin of 14 ng/mL, even if other iron labs are normal, as this pattern suggests iron deficiency despite the elevated serum iron. According to the most recent and highest quality study 1, a serum ferritin level of less than 15 μg/L is indicative of absent iron stores, and a level of less than 30 μg/L is generally indicative of low body iron stores. In this case, the ferritin level of 14 ng/mL is below the threshold, indicating depleted iron reserves.
The discrepancy between the serum iron and ferritin levels occurs because serum iron measures iron currently in the bloodstream, which can fluctuate throughout the day, while ferritin reflects the body's iron stores. Low ferritin indicates depleted iron reserves even when serum iron appears adequate. This pattern can occur with recent iron intake, certain inflammatory conditions, or early iron deficiency.
I recommend a complete evaluation by a healthcare provider and likely iron supplementation. Typically, ferrous sulfate 325 mg once or twice daily between meals is prescribed, though the doctor may recommend a different formulation or dosage based on the specific situation. The doctor should investigate potential causes of iron deficiency such as blood loss, poor absorption, or increased requirements. Follow-up testing after treatment is important to ensure that the iron stores are being replenished.
Key points to consider:
- Serum ferritin is the most specific test for iron deficiency in the absence of inflammation 1
- A serum ferritin level of less than 15 μg/L is highly specific for iron deficiency 1
- Iron deficiency can occur despite elevated serum iron levels, as serum iron only measures iron currently in the bloodstream 1
- A complete evaluation by a healthcare provider is necessary to determine the cause of iron deficiency and to guide treatment 1