What Is Polychromasia?

Reviewed by Dan Brennan, MD on April 24, 2021

Polychromasia occurs on a lab test when some of your red blood cells show up as bluish-gray when they are stained with a particular type of dye. This happens when red blood cells are immature because they were released too early from your bone marrow. These immature cells are called reticulocytes. 

What Causes Polychromasia?

Your red blood cells are the cells in your blood that carry oxygen to the rest of your body. These are made in your bone marrow, where they grow for about 7 days before they are released into your bloodstream. From there, they take the oxygen to other parts of your body. They also carry carbon dioxide from your body back to your lungs so that it can be exhaled during breathing.

Most of your blood is made up of red blood cells. They account for 40% to 45% of the total volume of your blood. They generally live for about 120 days before they die off and need to be replaced. Your kidneys produce a hormone called erythropoietin that tells your bone marrow to make more blood cells.


Certain blood disorders can cause your bone marrow to release blood cells early, and these cells show up as polychromasia on a blood test called a peripheral blood smear. Some conditions that can cause polychromasia include:

Hemolytic anemia. This condition is when your red blood cells are destroyed faster than they can be replaced. When you don't have enough red blood cells for your organs and tissues to get as much oxygen as they need, you develop anemia. Hemolytic anemia can be inherited, meaning you had it when you were born, or acquired, which means you developed it later in life.

Inherited anemia happens when your parents pass down the gene for the disease to you. Sickle cell anemia and thalassemia are two types of inherited hemolytic anemia. These types of anemia happen because your body makes abnormal blood cells that don't live as long as regular blood cells. 

Acquired hemolytic anemia can be caused by a number of different disorders. With acquired hemolytic anemia, your body produces normal red blood cells, but they are destroyed too quickly. Acquired hemolytic anemia can be caused by:

  • A reaction to a blood transfusion
  • Tumors
  • An overactive spleen, which is the organ responsible for destroying red blood cells
  • Viral or bacterial infections
  • Cancers of the blood
  • Lupus, rheumatoid arthritis, or other autoimmune diseases
  • Mechanical heart valves
  • Medicines, including acetaminophen, antimalarial medicine, penicillin, and sulfa medications


Hemorrhage. In cases where you have lost or are losing a lot of blood, polychromasia may show up on your peripheral blood smear. Hemorrhaging can be external, or outside of the body, from an injury or wound. The bleeding may also be internal and can occur in various parts of the body, including:

  • The abdomen
  • The chest
  • Around large bones that have broken
  • The digestive tract
  • The brain

Myeloid metaplasia. This condition can happen when your body makes red blood cells in places other than your bone marrow because your bone marrow has been infiltrated — or invaded by materials that shouldn’t be there — and isn't working correctly. It can happen with cancers such as lymphoma, multiple myeloma, and hairy cell leukemia.

Symptoms of Polychromasia

Polychromasia by itself doesn't cause symptoms. However, the underlying blood disorders that cause polychromasia may include symptoms such as:

  • Weakness
  • Fatigue
  • Easy bleeding
  • Paleness
  • Fever
  • Bone pain
  • Confusion
  • Enlarged spleen
  • Enlarged liver
  • Dizziness

How Is Polychromasia Diagnosed?

Polychromasia is diagnosed using a blood test called a peripheral blood smear. This test is performed by smearing a small sample of your blood on a slide, staining it with a special dye, and examining it under a microscope. A blood smear tells your doctor about the different types of cells and the amounts of each that are in your blood.  

A peripheral blood smear tells how many red blood cells, white blood cells, and platelets are in your blood. Polychromasia shows up when your red blood cells appear blue or gray when treated with the dye. This indicates they have more of a substance called ribonucleic acid (RNA) than normal red blood cells. Cells that have too much RNA are immature because they were released too soon from your bone marrow.   

Treatment Options for Polychromasia

The treatment for polychromasia will depend on the underlying cause, so talk to your doctor about your options. Some causes are temporary and will go away, while some causes are chronic and may be lifelong. Depending on the cause, treatment may include:

  • Blood transfusions
  • Treatment to make your immune system stronger
  • Corticosteroid medicines
  • Rituximab, a medicine used to treat certain types of cancer or rheumatoid arthritis
  • Surgery to remove your spleen in severe cases
  • Medicine to make your immune system weaker
WebMD Medical Reference



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American Society of Hematology: "Blood Basics."

Johns Hopkins Medicine: "Hemolytic Anemia."

Lab Tests Online: "Blood Smear."

Merck Manual: "Internal Bleeding."

Patient: "Bone Marrow and Bone Marrow Failure."

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