From the Guidelines
These lab values are consistent with iron deficiency anemia, and the patient should be treated with oral iron supplementation to replenish iron stores and improve quality of life. The low serum iron (45.0), low transferrin saturation (0.79%), and low MCV (74) and MCH (23) indicate microcytic, hypochromic anemia characteristic of iron deficiency, as supported by the British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults 1. The elevated red cell distribution width (22.8) further supports this diagnosis, showing increased variation in red blood cell size. The ferritin level of 40 is borderline low, though not severely depleted, and according to the guidelines, an SF value above 150 μg/L is unlikely to occur with absolute iron deficiency, even in the presence of inflammation, but a cut-off of 45 μg/L provides a respectable specificity of 0.92 for iron deficiency 1. Key points to consider in the treatment plan include:
- Oral iron supplementation, typically ferrous sulfate 325mg taken 1-3 times daily between meals with vitamin C to enhance absorption
- Therapy should continue for 3-6 months to replenish iron stores even after hemoglobin normalizes
- Investigating the cause of iron deficiency is essential, considering possibilities such as blood loss (menstruation, gastrointestinal bleeding), malabsorption, or dietary insufficiency
- Side effects of iron therapy may include constipation, nausea, and black stools
- If oral iron is not tolerated or ineffective, intravenous iron formulations may be considered
- Dietary counseling to increase iron-rich foods should complement pharmacological treatment.
From the Research
Interpretation of Laboratory Results
The provided laboratory results are:
- TIBC iron: 45.0
- Transferritin: 3.03
- TIBC: 76
- TIBC SAT: 0.79
- Ferritin: 40
- CBC:
- MCV: 74
- MCH: 23
- Red cell distribution width: 22.8
Diagnosis of Microcytic Anemia
The patient's MCV is 74, which is below the normal range, indicating microcytic anemia 2, 3, 4. Microcytic anemia is defined as the presence of small, often hypochromic, red blood cells in a peripheral blood smear and is usually characterized by a low MCV (less than 83 micron 3) 2.
Iron Deficiency Anemia
The serum ferritin level is 40, which is within the normal range, but the transferrin saturation (TIBC SAT) is 0.79, which is low 5, 6. The total iron-binding capacity (TIBC) is 76, which is elevated 5. These results suggest that the patient may have iron deficiency anemia, but the diagnosis is not definitive without further evaluation 2, 5, 3, 4, 6.
Differential Diagnosis
Other causes of microcytic anemia, such as thalassemia, anemia of chronic disease, and sideroblastic anemia, should be considered 2, 5, 3, 4. Further testing, such as hemoglobin electrophoresis, may be necessary to differentiate between these conditions 5, 3.
Evaluation and Management
The patient's underlying cause of iron deficiency anemia should be investigated, and treatment should be tailored to the underlying cause 2, 5, 3, 4, 6. Oral iron supplementation is typically the first-line treatment for iron deficiency anemia, but intravenous iron may be necessary in certain cases, such as malabsorption or ongoing blood loss 5, 6.