Elliptocytes are usually not dangerous. These oval or elongated red blood cells appear on blood tests for a variety of reasons, and in most cases they cause no symptoms and require no treatment. When elliptocytes do signal a problem, the underlying cause matters far more than the cell shape itself.
What Elliptocytes Are
Normal red blood cells are round, disc-shaped cells about 7.5 micrometers across, with a slight indentation in the center. Elliptocytes are red blood cells that have stretched into an oval or elongated cigar shape instead. A small number of elliptocytes can appear in anyone’s blood and is considered normal. They become clinically significant when they make up a larger proportion of your red blood cells, typically at least 25% of cells on a blood smear.
Finding elliptocytes on a routine blood test doesn’t automatically mean something is wrong. It’s a clue that prompts your doctor to look further, not a diagnosis on its own.
The Most Common Cause: Hereditary Elliptocytosis
Hereditary elliptocytosis (HE) is an inherited condition where a defect in the proteins that form the red blood cell’s internal skeleton causes the cells to lose their round shape. The structural proteins involved, primarily spectrin and protein 4.1, act like scaffolding inside the cell membrane. When mutations affect these proteins, the membrane becomes mechanically weak and the cell deforms into an elliptical shape.
The vast majority of people with hereditary elliptocytosis have no symptoms at all. Many never know they have it unless it turns up incidentally during a blood test for something else. Only about 5% to 20% of people with the condition develop significant red blood cell breakdown (hemolysis) that leads to anemia. For the remaining 80% to 95%, the condition is entirely benign and requires no treatment.
When Elliptocytes Can Cause Problems
In the small minority of hereditary elliptocytosis cases where red blood cells break down faster than the body can replace them, symptoms of anemia can develop. These include fatigue, pale skin, shortness of breath, and a rapid heart rate. Chronic red blood cell destruction can also lead to an enlarged spleen, jaundice (yellowing of the skin and eyes), and gallstones, which form when the breakdown products of red blood cells accumulate in the gallbladder.
Newborns with the condition sometimes experience a temporary period of more severe red blood cell breakdown that improves on its own within the first year or two of life. In rare, severe cases, surgical removal of the spleen may be considered because the spleen is the organ primarily responsible for filtering and destroying the misshapen cells. Without the spleen clearing them out, more elliptocytes survive in the bloodstream, and anemia improves.
Elliptocytes From Other Conditions
Elliptocytes don’t always point to an inherited disorder. They frequently show up alongside other conditions, and in these cases, treating the underlying problem resolves the abnormal cell shapes.
- Iron deficiency anemia: One of the most common causes of elliptocytes worldwide. When iron stores are low, red blood cells become small and pale, and some take on a thin, pencil-like elliptical shape. Correcting the iron deficiency returns cells to their normal shape.
- Vitamin B12 or folate deficiency: Megaloblastic anemia caused by low B12 or folate produces abnormally large red blood cells, some of which appear as elliptocytes alongside teardrop-shaped cells. Supplementing the missing vitamin resolves the issue.
- Bone marrow disorders: Conditions affecting the bone marrow, such as myelofibrosis, can produce elliptocytes as part of a broader pattern of abnormally shaped red blood cells. These are more serious conditions, but the elliptocytes themselves are a symptom rather than the core problem.
The key distinction is that elliptocytes caused by nutritional deficiencies disappear once the deficiency is corrected. Elliptocytes from hereditary elliptocytosis are present for life, though they rarely cause harm.
What Happens After Elliptocytes Are Found
If a blood smear shows a significant number of elliptocytes, your doctor will typically check for the most common and treatable causes first: iron levels, B12, and folate. A complete blood count reveals whether you’re anemic and, if so, what type. If nutritional deficiencies are ruled out and elliptocytes make up 25% or more of your red blood cells, hereditary elliptocytosis becomes the likely explanation, especially if there’s a family history.
For the majority of people with hereditary elliptocytosis, no ongoing treatment is needed. You may simply be told that this is a normal finding for you. If you do have anemia from red blood cell breakdown, monitoring with periodic blood tests helps ensure it stays manageable. Folic acid supplementation is sometimes recommended because your body uses more folate when it’s constantly producing new red blood cells to replace destroyed ones.
The bottom line: elliptocytes on a blood test are worth investigating, but they are rarely dangerous on their own. In most cases, they either reflect a treatable nutritional deficiency or an inherited trait that causes no symptoms for the vast majority of people who have it.