Refractory anemia is anemia that does not improve with the usual fixes such as iron, vitamin B12, or folate, because the problem lies in the bone marrow itself. In hematology the term most often refers to a low-risk form of myelodysplastic syndrome (MDS), a condition in which marrow stem cells acquire genetic damage and produce red cells that are faulty or die before release. It is diagnosed with blood tests and a bone marrow biopsy, and treated with transfusions, growth factors, or targeted drugs depending on its subtype and risk.
Below I explain what the term means today, why it happens, how it is confirmed, and what the treatment options look like.
What Is Refractory Anemia?
The word “refractory” simply means resistant to treatment. Doctors sometimes use it loosely for any anemia that has not responded as expected, which should always prompt a search for a missed cause such as ongoing blood loss, poor absorption, or kidney disease.
As a formal diagnosis, refractory anemia was a named subtype of MDS in older classification systems. MDS is a group of bone marrow disorders in which the marrow cells look abnormal (dysplastic) and blood production is ineffective. Current classifications now describe these cases as MDS with low blasts, but “refractory anemia” is still widely used by patients and on older reports.
It belongs to the broader group of hematological disorders, and like other MDS types it carries some risk of progressing to acute myeloid leukemia (AML), though the risk in low-grade forms is comparatively small.
Refractory Anemia Subtypes
The older system split this group by what the marrow showed. These names still appear in medical records, so it helps to recognize them.
| Older name | Key marrow finding | Current equivalent (approximate) |
|---|---|---|
| Refractory anemia (RA) | Dysplasia mainly in red cell precursors; blasts under 5% | MDS with low blasts, single-lineage dysplasia |
| Refractory anemia with ring sideroblasts (RARS) | Iron-laden “ring” precursors; often an SF3B1 mutation | MDS with low blasts and SF3B1 mutation / ring sideroblasts |
| Refractory cytopenia with multilineage dysplasia (RCMD) | Dysplasia in two or more cell lines | MDS with low blasts, multilineage dysplasia |
| Refractory anemia with excess blasts (RAEB) | Blasts 5% to 19% | MDS with increased blasts (higher risk) |
Blasts are immature cells. The higher their proportion in the marrow, the higher the risk of transformation to AML, which is why blast count is central to both classification and treatment decisions.
Causes and Risk Factors
Refractory anemia arises when a blood stem cell acquires mutations that disrupt normal maturation. The affected clone keeps dividing, but many of its red blood cells die inside the marrow before they are released, a process called ineffective erythropoiesis.
Commonly found mutations include SF3B1, TET2, DNMT3A, and TP53, and chromosome changes such as deletion of part of chromosome 5 (del(5q)) or chromosome 7. Recognized risk factors are:
- Older age, as MDS is mainly a disease of people over 60
- Previous chemotherapy or radiation therapy for another cancer
- Long-term exposure to benzene and some industrial chemicals
- Smoking
- Certain inherited marrow failure syndromes, in younger patients
In most people no specific trigger is found. It is not contagious and, in older adults, rarely inherited.
Symptoms of Refractory Anemia
Symptoms reflect a shortage of healthy red blood cells carrying oxygen. They develop gradually, so many people put them down to aging.
- Persistent tiredness and low stamina
- Shortness of breath on exertion
- Pale skin
- Dizziness, palpitations, or chest pain in more severe anemia
- Bruising or infections if platelets or white cells are also low
Some patients have no symptoms and are picked up on a routine blood test showing low hemoglobin with red cells that are larger than normal.
How Refractory Anemia Is Diagnosed
The first step is ruling out common, fixable causes. That means checking iron studies, vitamin B12, folate, kidney and thyroid function, and looking for blood loss. Only when these are normal, or corrected without improvement, does marrow disease move to the top of the list.
| Test | Typical finding in refractory anemia |
|---|---|
| Complete blood count | Low hemoglobin (below about 13 g/dL in men, 12 g/dL in women); other counts may be low |
| Mean corpuscular volume (MCV) | Normal or high (macrocytic) |
| Reticulocyte count | Low for the degree of anemia |
| Blood smear | Abnormally shaped red cells, poorly granulated neutrophils |
| Bone marrow biopsy | Dysplasia, blast percentage, ring sideroblasts on iron stain |
| Cytogenetics and gene panel | Chromosome changes and mutations such as SF3B1 or del(5q) |
Bone marrow aspiration and biopsy is essential, because it shows how the bone marrow is functioning and allows genetic testing. The results feed into a risk score, most commonly the Revised International Prognostic Scoring System (IPSS-R) or its molecular update, which guides treatment.
Treatment Options
For lower-risk refractory anemia, the aim is to relieve anemia and maintain quality of life. Someone with mild, stable anemia may simply be monitored.
- Red cell transfusions relieve symptoms when hemoglobin falls too low.
- Iron chelation removes excess iron that builds up after many transfusions.
- Erythropoiesis-stimulating agents (ESAs), lab-made erythropoietin, work best when the body’s own erythropoietin level is not already high.
- Luspatercept helps red cells mature and is used especially in patients with ring sideroblasts or SF3B1 mutations.
- Lenalidomide is particularly effective in MDS with isolated del(5q).
For higher-risk disease, hypomethylating agents such as azacitidine or decitabine can slow progression. Allogeneic stem cell transplant is the only potentially curative option, but its risks mean it is reserved for fitter patients with higher-risk features. Our anemia guide covers the more common causes of anemia for comparison.
When to See a Doctor
See your doctor if you have ongoing fatigue or breathlessness, or if your anemia has not improved after several weeks of iron or vitamin treatment. Ask for a referral to a hematologist if your red cells are enlarged without B12 or folate deficiency, or if more than one blood count is low. Seek prompt care for frequent infections, unusual bleeding, or chest pain. A specialist grounded in haematology can decide whether a marrow examination is needed.
Frequently Asked Questions
Is refractory anemia a type of cancer?
MDS, including refractory anemia, is classified as a blood cancer because it arises from a clone of abnormal marrow cells. Low-risk forms often behave more like a chronic condition, and many people live with them for years with supportive care.
Can refractory anemia turn into leukemia?
It can, but the risk depends heavily on the subtype. Low-blast forms carry a relatively low risk, while cases with excess blasts or high-risk mutations such as TP53 carry a higher one. Regular blood counts help catch any change early.
Why doesn’t iron help refractory anemia?
The body usually has enough iron; the marrow simply cannot use it properly to make healthy red cells. Extra iron can even add to the iron overload that builds up from transfusions.
How often will I need blood transfusions?
This varies from none at all to every few weeks, depending on how low your hemoglobin runs and how you feel. Treatments such as ESAs, luspatercept, or lenalidomide can reduce or stop the need for transfusions in some patients.
