If your blood smear test results show multicolored red blood cells (RBCs), this may be a sign of polychromasia. Polychromasia can be caused by a variety of underlying blood disorders, including cancer.

Polychromasia is the presentation of multicolored red blood cells (RBCs) 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, various blood disorders may cause it. It’s important to find the underlying cause so that you can receive treatment right away.

In this article, we 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, it’s helpful to know the concept behind a blood smear test, or a peripheral blood film.

Peripheral blood film

A peripheral blood film can be used to diagnose and monitor diseases that affect your blood cells.

During the test, a pathologist first smears a slide with a sample of your blood. Then they stain 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

RBCs are formed in your bone marrow.

Polychromasia is caused when bone marrow prematurely releases immature RBCs called reticulocytes.

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 can likely be the cause.

Treating certain blood disorders, especially those related to bone marrow function, can also lead to polychromasia. In such cases, polychromasia becomes a treatment side effect 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 anemiaThis occurs due to an increased destruction of RBCs and causes an increased turnover of RBCs.
paroxysmal nocturnal hemoglobinuria (PNH)PNH can cause hemolytic anemia, blood clots, and bone marrow dysfunction. Bone marrow dysfunction can possibly bring on early release of RBCs.
certain cancersSome cancers can affect RBC production.
radiation therapyThis can cause increased destruction of RBCs.

Hemolytic anemia

Hemolytic anemia is a type of anemia that occurs when your body cannot 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 types of conditions cause an increased turnover of RBCs and polychromasia.

Paroxysmal nocturnal hemoglobinuria (PNH)

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disease 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 in the bone marrow and can greatly influence RBC production.

Additionally, when any type of cancer spreads within the body, it can cause further destruction of RBCs. These types of metastatic 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 and 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 PNH 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, a medical professional will likely order 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.

But it’s important to keep in mind that polychromasia is not the only way to diagnose these conditions, so a doctor may not even mention it during a diagnosis.

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

  • Blood transfusions: Blood transfusions can help to restore RBC count in conditions like anemia.
  • Medications: Growth factors are a type of medication that can stimulate RBC production.
  • Immunotherapy: Immunotherapy can treat infections and conditions that deplete RBC count.
  • Chemotherapy: Chemotherapy can treat cancers that affect RBC count.
  • Bone marrow transplant: Bone marrow transplants are typically used for serious conditions involving bone marrow dysfunction.

If you’ve been diagnosed with any of the conditions that can cause polychromasia, a doctor can help you find the safest and most effective treatment options.

What is the difference between polychromasia and hypochromic?

While polychromasia results in multicolored RBCs on a blood smear test, if your red blood cells appear lighter in color, it’s called hypochromic.

RBCs that have a reduced red color may be a sign of microcytic, hypochromic anemia. This type of anemia can result from low blood iron levels.

A healthcare professional can help determine if your blood iron levels are low through blood tests.

What does it mean if you have immature red blood cells (RBCs)?

Your body makes RBCs in the bone marrow that are released into the bloodstream. They mature after about 1–2 days.

Sometimes, however, these immature blood cells, called reticulocytes, are released prematurely.

If you have increased levels of these reticulocytes, it may be a sign of anemia or bone marrow dysfunction.

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.