Poikilocytosis: Definition, Causes, Symptoms and Treatments of This Abnormal Variation of Erythrocytes

The term “poikilocyte” is a generic term to describe red blood cells that are abnormal in shape.

Poikilocytes can be subclassified by specific shape changes, some of which have relatively unique diagnostic significance, while other forms are pretty nonspecific.

Wherever possible, the shape of the red blood cells should be specifically identified, e.g., acanthhocytes, keratocytes, schistocytes, and the generic term poikilocytosis or poikilocytes should be avoided.

However, in some situations, there are so many red blood cells or some forms that defy the description that the generic term poikilocytosis is sufficient and provides the same information as identifying each formation of red blood cells individually.

In all cases, the complete interpretation of red blood cell changes can only be made in light of the other CBC parameters, along with pertinent clinical, historical, and laboratory findings.

Evaluation of significant abnormalities in shape requires a well-done blood smear prepared from fresh blood so that changes in artifact shape do not overlap with any potential pathological significance.

Poikilocytosis refers to the abnormality in red blood cell morphology documented in stained blood smears or as seen by scanning electron microscopy. Most of the specific poikilocytes are associated with the disease.


Many compounds are designed to be cationic, hydrophobic, and lipophilic to enhance their ability to penetrate plasma membranes.

These qualities also allow the intercalation of xenobiotics in the lipid bilayer of erythrocytes. This quality is responsible for the observation of pinocytosis and acanthocytosis.

Acanthocytes are erythrocytes with short membrane protrusions (spikes) that occur with irregular shape and incidence around the cell’s perimeter.

They should not be confused with schistocytes, which have plasma membranes that have spikes of uniform size and are evenly distributed in the cytoplasmic membrane and often occur artificially from dried blood smears but can also be secondary to renal toxicity.

The diagnostic relevance of poikilocytes depends on the number, shape, and context. Variable numbers of misshapen red blood cells can be seen in the blood of clinically normal or diseased patients, and these findings may not be of diagnostic relevance.

Poikilocytosis refers to the presence in the blood of poikilocytes. In a blood smear, poikilocytes are abnormally shaped red blood cells.

Rather than being seen as a sign of any disease, poikilocytosis is a reasonably general condition.

However, there may be a predominance of a particular type of abnormally shaped red blood cells, some of which may indicate the possible presence of a specific disease or disorder.

Normal red blood cells are round, flattened discs thinner in the middle than at the edges, whereas in a poikilocyte, there may be a distortion of that standard shape or a completely different shape.

In general, poikilocytosis can refer to an increase in abnormal red blood cells of any form in which they constitute 10% or more of the total population.

Causes of poikilocytosis

Abnormal red blood cells are seen in many conditions, so poikilocytosis is not specific. However, particular poikilocytes can be seen in disease states and specific disorders.


Some medications, such as doxorubicin, can induce poikilocytosis.

membrane abnormalities

  • Acanthocytes or spur/spike cells.
  • Target cells or elbows.
  • Echinocytes and Burr Cells.
  • Elliptocytes and ovalocytes.
  • Osherocytes.
  •  Buccal cells or stomatocytes.


  • Dacrocytes or tear cells.
  • Keratocytes.
  • Microspherocytes.
  • Schistocytes.
  • The semilunar bodies.

Symptoms of poikilocytosis

The primary sign of poikilocytosis has more than 10 percent abnormally shaped red blood cells.

Symptoms will depend on the condition causing the poikilocytosis.

However, generally, symptoms associated with blood-related disorders, such as anemia, include:

  • Soft spot.
  • Short of breath.
  • Fatigue.
  • Pale skin.

Treatment of poikilocytosis

In all cases, the treatment of poikilocytosis depends on the cause that causes these changes in shape.

Thus, for example, poikilocytosis can be caused by a vitamin deficiency, in which case the treatment is to administer vitamin B12 or folic acid.

It can also be caused by a digestive disease, such as celiac disease. The solution may lie in treating the underlying celiac disease with diets so that the nutrients can be absorbed appropriately.