From the Guidelines
A ferritin level of 20 ng/mL in a postmenopausal woman indicates iron deficiency that requires treatment, and I strongly recommend starting oral iron supplementation with ferrous sulfate 325 mg once or twice daily, taken on an empty stomach with vitamin C to enhance absorption, as the AGA suggests a cutoff of 45 ng/mL for diagnosing iron deficiency, but treatment should not be delayed in symptomatic patients or those with low ferritin levels 1.
Diagnosis and Treatment
The American Gastroenterological Association (AGA) recommends using a cutoff of 45 ng/mL for diagnosing iron deficiency in patients with anemia, but in this case, the patient's low ferritin level of 20 ng/mL warrants immediate treatment to alleviate symptoms and improve quality of life 1.
- The AGA suggests bidirectional endoscopy in asymptomatic postmenopausal women and men with iron deficiency anemia, but this may not be necessary in all cases, especially if the patient is asymptomatic and has no other risk factors for gastrointestinal bleeding 1.
- However, it is essential to investigate potential causes of blood loss, particularly gastrointestinal bleeding, since menstrual blood loss is no longer a factor in postmenopausal women.
- Noninvasive testing for Helicobacter pylori, followed by treatment if positive, may also be beneficial in resolving iron deficiency, as H pylori infection can decrease iron absorption and is associated with gastric adenocarcinoma 1.
Management and Follow-up
- Continue iron supplementation for at least 3-6 months, even after symptoms improve, to fully replenish iron stores.
- During treatment, avoid taking iron with calcium supplements, dairy products, tea, coffee, or antacids, as these can reduce absorption.
- Side effects of iron supplementation may include constipation, nausea, and black stools; increasing fiber and fluid intake can help manage constipation.
- Schedule a complete blood count to check for anemia and consult with your doctor about potential endoscopic evaluation to rule out gastrointestinal sources of bleeding.
From the Research
Diagnosis and Interpretation of Low Ferritin Levels
- A ferritin level of 20 μg/L in a postmenopausal lady is considered low, indicating potential iron deficiency 2.
- The diagnosis of iron deficiency is largely based on biochemical and haematological laboratory findings, with ferritin measurement being the most important analysis 2.
- However, there is no consensus on the diagnostic cut-off for ferritin levels, with some studies suggesting a cut-off of 30 μg/L for detecting iron deficiency 3, 2.
Causes and Evaluation of Iron Deficiency Anemia
- Iron deficiency anemia (IDA) is the most common form of anemia worldwide, and in postmenopausal women, the commonest cause of IDA is blood loss from lesions in the gastrointestinal tract 4.
- Gastrointestinal evaluation is almost always indicated to exclude gastrointestinal malignancy in patients with IDA 4.
- Specific patient groups, such as postmenopausal women with low-normal ferritin, may need an individualized approach to diagnosis and management 4.
Diagnostic Accuracy of Ferritin Concentrations
- Ferritin concentrations can be used as a diagnostic test for iron deficiency and overload, but its accuracy can be affected by inflammation and infection 5.
- A systematic review found that at a threshold of 30 μg/L, blood ferritin concentration is reasonably sensitive and very specific for iron deficiency in people presenting for medical care, but there is insufficient evidence to know whether ferritin concentration performs similarly when screening asymptomatic people for iron deficiency or overload 5.