From the Guidelines
Low serum iron and ferritin levels in a 78-year-old female suggest iron deficiency, even with a negative FIT test and normal Hgb/Hct. This patient requires further evaluation to determine the cause of her iron deficiency. According to the British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults 1, a serum ferritin level of <15 μg/L is highly specific for iron deficiency, and a cut-off of 45 μg/L provides a respectable specificity of 0.92. In this case, the patient's ferritin level of 21 μg/L is below the suggested cut-off, indicating possible iron deficiency.
Initial workup should include a complete gastrointestinal evaluation, focusing on potential sources of blood loss or malabsorption. A colonoscopy and upper endoscopy would be appropriate to rule out gastrointestinal bleeding sources, particularly colorectal cancer or peptic ulcer disease. While starting oral iron supplementation (such as ferrous sulfate 325 mg daily) is reasonable, identifying and addressing the underlying cause is essential. Iron deficiency in elderly patients often precedes anemia, as iron stores deplete before hemoglobin levels fall. The normal Hgb/Hct with low iron parameters represents early iron deficiency, where the body has depleted iron stores but still maintains adequate hemoglobin production.
The negative FIT test only rules out significant lower GI bleeding at the time of testing but doesn't exclude intermittent bleeding or upper GI sources. Given the patient's age, a thorough investigation is warranted even without overt anemia. The European Consensus on the Diagnosis and Management of Iron Deficiency and Anaemia in Inflammatory Bowel Diseases 1 also emphasizes the importance of distinguishing between iron deficiency anaemia and anaemia of chronic disease, particularly in patients with inflammatory conditions. However, in this case, the primary concern is the patient's iron deficiency, and further evaluation should focus on identifying the underlying cause.
From the Research
Iron Deficiency Indicators
- The patient's serum iron level is 14.7, which is considered low, and the ferritin level is 21, indicating depleted iron stores 2.
- The patient's Hemoglobin (Hgb) and Hematocrit (Hct) levels are within normal ranges, but these parameters may not be reliable indicators of iron deficiency, especially in the early stages 2.
- A negative Fecal Immunochemical Test (FIT) suggests that there is no overt gastrointestinal bleeding, but it does not rule out the possibility of iron deficiency 3.
Diagnostic Considerations
- The diagnosis of iron deficiency requires a comprehensive evaluation of iron status, including serum iron, ferritin, and transferrin saturation levels 2, 4.
- In patients with inflammatory conditions, serum ferritin levels may be elevated, making it a less reliable marker for iron deficiency; in such cases, transferrin saturation (TSAT) should also be assessed 4.
- The patient's age and lack of gastrointestinal symptoms do not preclude the possibility of iron deficiency, and further evaluation may be necessary to determine the underlying cause of the low serum iron and ferritin levels 5, 3.