Polychromasia is the presentation of multicolored red blood cells in a blood smear test. It’s an indication of red blood cells being released prematurely from bone marrow during formation.

While polychromasia itself isn’t a condition, it can be caused by an underlying blood disorder. When you have polychromasia, it’s important to find the underlying cause so that you can receive treatment right away.

In this article, we’ll discuss what polychromasia is, what blood disorders can cause it, and what the symptoms might be for those underlying conditions.

To understand what polychromasia is, you must first understand the concept behind a blood smear test, also known as a peripheral blood film.

Peripheral blood film

A peripheral blood film is a diagnostic tool that can be used to diagnose and monitor diseases that affect blood cells.

During the test, a pathologist smears a slide with a sample of your blood and then stains the slide to view the different types of cells within the sample.

The dye that’s added to the blood sample in a peripheral blood film can help differentiate various cell types. For example, common cell colors can range from blue to deep purple, and more.

Typically, red blood cells turn a salmon pink color when stained. However, with polychromasia, some stained red blood cells may appear blue, bluish gray, or purple.

Why red blood cells turn blue

Red blood cells (RBCs) are formed in your bone marrow. Polychromasia is caused when immature RBCs, called reticulocytes, are released prematurely from bone marrow.

These reticulocytes appear on a blood film as a bluish color because they still contain RNA fragments, which aren’t usually present on mature RBCs.

Conditions that affect RBC turnover are generally the root cause of polychromasia.

These types of conditions can result in increased blood loss and the destruction of RBCs, which in turn can increase RBC production. This can cause reticulocytes to be released into the blood prematurely as the body compensates for the lack of RBCs.

If a doctor has noted that you have polychromasia, there are several underlying conditions that are most likely the cause.

The treatment of certain blood disorders (especially those related to bone marrow function) can also lead to polychromasia. In such cases, polychromasia becomes a side effect of the treatment rather than a sign of the disease.

The table below lists the most common conditions that can cause polychromasia. More information about each condition and how they affect RBC production follows the table.

Underlying conditionEffect on RBC production
hemolytic anemiaoccurs due to an increased destruction of RBCs, causes an increased turnover of RBCs
paroxysmal nocturnal hemoglobinuria (PNH)can cause hemolytic anemia, blood clots, and bone marrow dysfunction — the latter possibly bringing on early release of RBCs
certain cancerscan affect production of RBCs
radiation therapycan cause increased destruction of RBCs

Hemolytic anemia

Hemolytic anemia is a type of anemia that occurs when your body can’t produce RBCs as quickly as they’re being destroyed.

Many conditions can cause RBC destruction and lead to hemolytic anemia. Some conditions, such as thalassemia, cause dysfunctional RBCs, which can also lead to hemolytic anemia. Both of these types of conditions cause an increased turnover of RBCs and polychromasia.

Paroxysmal nocturnal hemoglobinuria (PNH)

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder that causes hemolytic anemia, blood clots, and bone marrow dysfunction.

With this disease, RBC turnover is most affected by hemolytic anemia. Bone marrow dysfunction may also cause the body to overcompensate and release RBCs early. Both can lead to polychromasia on blood smear results.

Certain cancers

Not all cancers affect RBC turnover. However, blood cancers can greatly affect the health of your blood cells.

Certain blood cancers, such as leukemia, start at the bone marrow and can greatly influence RBC production. In addition, when any type of cancer has spread across the body, it can cause further destruction of RBCs. These types of cancers are likely to show polychromasia during blood testing.

Radiation therapy

Radiation therapy is an important treatment option for cancer. However, almost all types of cancer treatment affect both cancer cells as well as healthy cells.

In some cases, radiation therapy can cause changes in the way blood cells look. This may lead to polychromasia when your blood is retested.

There are no symptoms directly associated with polychromasia. However, there are symptoms associated with the underlying conditions that cause polychromasia.

Symptoms of hemolytic anemia

Symptoms of hemolytic anemia include:

  • pale skin
  • lightheadedness or dizziness
  • weakness
  • confusion
  • heart palpitations
  • enlarged liver or spleen

Symptoms of paroxysmal nocturnal hemoglobinuria

Symptoms of paroxysmal nocturnal hemoglobinuria include:

  • symptoms of hemolytic anemia (listed above)
  • recurring infections
  • bleeding issues
  • blood clots

Symptoms of blood cancers

Symptoms of blood cancers include:

  • night sweats
  • unintentional weight loss
  • bone pain
  • swollen lymph nodes
  • enlarged liver or spleen
  • fever and constant infections

If you have any of these symptoms, your doctor will likely want to run some blood tests to determine if you have any of the associated underlying conditions.

At that time, they’ll be able to detect polychromasia on a blood smear if it’s present. However, it’s important to keep in mind that polychromasia isn’t the only way to diagnose these conditions, and therefore your doctor may not even mention it upon diagnosis.

Treatment for polychromasia depends on the type of blood disorder that’s causing it. Treatment options may include:

  • blood transfusions, which can help to restore RBC count in conditions like anemia
  • medications, such as growth factors, that can stimulate RBC production
  • immunotherapy, to treat infections and conditions that deplete RBC count
  • chemotherapy, for the treatment of cancers that affect RBC count
  • bone marrow transplant, for serious conditions involving bone marrow dysfunction

If you’ve been diagnosed with any of the conditions that can cause polychromasia, talk to your doctor about the safest, most effective treatment options for you.

Polychromasia can be a sign of a serious blood disorder, such as hemolytic anemia or blood cancer.

Polychromasia, as well as the specific blood disorders that cause it, can be diagnosed via a blood smear test. There are no symptoms for polychromasia itself. However, the underlying conditions causing polychromasia can cause a variety of different symptoms.

If you have polychromasia, it’s important to meet with a doctor to diagnose the underlying condition and discuss treatment options.