From the Guidelines
Low hemoglobin and ferritin levels are primarily caused by iron deficiency, which can result from inadequate dietary iron intake, poor iron absorption, or blood loss, and the most recent and highest quality study 1 recommends that treatment typically involves oral iron supplements and addressing the underlying cause.
Causes of Low Hemoglobin and Ferritin Levels
- Inadequate dietary iron intake
- Poor iron absorption due to conditions like celiac disease, Crohn's disease, or gastric bypass surgery
- Blood loss from heavy menstrual periods, gastrointestinal bleeding from ulcers or inflammatory bowel disease, and frequent blood donation
- Pregnancy, which increases iron requirements
- Chronic kidney disease, which reduces erythropoietin production
- Chronic inflammation from conditions like rheumatoid arthritis or cancer, which can trap iron in storage
- Certain medications like proton pump inhibitors that reduce iron absorption
- Genetic disorders like thalassemia
Diagnosis and Treatment
- Diagnosis involves measuring serum ferritin levels, transferrin saturation, and complete blood count with MCV and reticulocytes
- Treatment typically involves oral iron supplements such as ferrous sulfate 325mg daily, addressing the underlying cause, and in severe cases, intravenous iron therapy
- Iron supplements should be taken with vitamin C to enhance absorption and between meals to avoid interference from calcium and tannins in food
- Improvement in levels usually takes several weeks to months of consistent supplementation, as noted in the study 1
Important Considerations
- The presence of inflammation can affect the interpretation of ferritin levels, and other markers of inflammation such as C-reactive protein or measures of iron status like total iron binding capacity should be considered, as mentioned in the study 1
- The soluble transferrin receptor (sTfR) can help diagnose iron deficiency in patients with inflammatory conditions, but its availability and interpretation may be limited, as discussed in the study 1
- Reticulocyte hemoglobin content is a direct assessment of the functional availability of iron to the erythropoietic tissue and can be useful in monitoring response to therapy, as noted in the study 1
From the Research
Causes of Low Hemoglobin and Ferritin Levels
- Chronic kidney disease (CKD) is a common cause of low hemoglobin and ferritin levels, as it leads to absolute and functional iron deficiency 2, 3, 4
- Absolute iron deficiency is defined by severely reduced or absent iron stores, while functional iron deficiency is defined by adequate iron stores but insufficient iron availability for incorporation into erythroid precursors 2
- Risk factors contributing to absolute and functional iron deficiency in CKD include blood losses, impaired iron absorption, and chronic inflammation 3
- Hepcidin, a key regulator of iron availability, plays a crucial role in the development of anemia in CKD, as its increased levels lead to iron sequestration 4
- Other causes of low hemoglobin and ferritin levels may include:
Diagnosis and Treatment of Iron-Deficiency Anemia
- Diagnosis of iron-deficiency anemia in CKD patients is complicated by the relatively poor predictive ability of routine serum iron indices, such as ferritin and transferrin saturation 5
- Emerging alternative markers of iron stores, such as hepcidin, may improve the diagnosis of iron-deficiency anemia in CKD patients 4
- Treatment of iron-deficiency anemia in CKD patients typically involves iron supplementation, either orally or intravenously, and erythropoietic-stimulating agents 2, 3, 6
- The choice of iron supplementation route depends on the individual patient's needs and circumstances, with intravenous iron supplementation generally recommended for CKD patients on dialysis 2, 3