A complete blood count (CBC) might suggest hemolytic anemia if your RBC, hemoglobin, and reticulocyte counts are low. But further testing may be required.
Anemia occurs when you don’t have enough healthy red blood cells (RBCs) to transport oxygen throughout your body.
Hemolytic anemia is a subtype of anemia that is due to hemolysis, the breakdown of RBCs. Hemolytic anemia can be inherited or acquired.
A complete blood count (CBC) can provide information about how many RBCs you have and may also provide clues as to why your RBC count is low. Still, it’s usually not enough to confirm hemolytic anemia, so doctors often order further tests.
In this article, we explain how CBC results may indicate hemolytic anemia and what other testing may be required.
Symptoms of hemolytic anemia
Symptoms of hemolytic anemia may worsen over time and include:
- fatigue, which may become extreme
- yellowing of your skin or eyes (jaundice)
- pale or washed-out skin
- dark urine
- feelings of overall body weakness
- cold hands and feet
- fast heart rate
A CBC is a simple blood test you may undergo in a healthcare setting, such as a doctor’s office or laboratory. Healthcare professionals use this test to measure and analyze RBCs, white blood cells (WBCs), and platelets.
These CBC measurements can help a healthcare professional determine if you have hemolytic anemia:
Red blood cell count
Your RBC count is the number of RBCs circulating throughout your body.
What doctors consider a typical RBC count range depends on your age and sex assigned at birth. These values can vary between labs, but in general are:
- 4.2 to 5.4 million cells per microliter (cells/μL) for females
- 4.7 to 6.1 million cells/μL for males
Hemoglobin, a protein, is the main component of RBCs. Hemoglobin contains iron, which binds to oxygen. This enables RBCs to transport oxygen from your lungs to the rest of your body.
Hemoglobin levels below
Mean corpuscular volume (MCV)
MCV measures the size and volume of RBCs, which can help identify the type of anemia you have.
In hemolytic anemia, RBCs are usually of typical size. This means your MCV will be in the
Reticulocytes are immature RBCs. An abnormally high reticulocyte count indicates that your bone marrow is trying to replace destroyed RBCs at a rapid pace.
If a healthcare professional suspects you have hemolytic anemia, they will include this test in a CBC. If not, they may conduct the test separately at a later date.
While a CBC can confirm anemia, a doctor will need other tests to confirm hemolytic anemia. These include:
- Peripheral blood smear: A blood smear can detect changes in RBC shape, which may indicate the type of anemia.
- Haptoglobin test: Haptoglobin is a protein that binds to free hemoglobin. A low haptoglobin count means you have too much hemoglobin not attached to RBCs, suggesting hemolytic anemia.
- Bilirubin test: Hemoglobin breaks down into bilirubin. A high bilirubin count suggests an increased breakdown of hemoglobin and possible hemolytic anemia.
- Lactase dehydrogenase (LDH) test: RBCs release LDH when they break down. A high LDH count typically suggests hemolysis.
- Hemoglobinuria test: This urine test can detect high levels of hemoglobin.
- Coombs test: Also known as an antiglobulin test, a Coombs test looks for antibodies that destroy RBCs. This can help identify autoimmune hemolytic anemia.
- Bone marrow tests: If blood tests are inconclusive, bone marrow tests can help determine if your bone marrow is producing enough healthy blood cells. A doctor may perform this test via needle aspiration or extracting a sample of solid bone marrow (core biopsy), usually from your hip bone.
- Genetic testing: Doctors can perform genetic tests on amniotic fluid before birth or on blood after birth. These tests identify the presence of hereditary conditions that can cause hemolytic anemia, such as sickle cell disease.
A healthcare professional will work with you on a treatment plan to reduce your risk of hemolysis. This may include strategies such as avoiding cold weather and staying warm indoors.
Reducing your risk of infection and illness will be important. A doctor may recommend getting annual vaccinations and avoiding large crowds. You may also need to avoid undercooked or raw food that can cause food-borne illnesses.
Treatments for hemolytic anemia vary based on the type you have and its underlying cause:
- If your immune system is producing antibodies that attack your RBCs, a doctor may recommend steroid therapy or immunosuppressive therapy.
- Intravenous (IV) medications, such as immunoglobulin (IVIG), may strengthen your immune system.
- If your condition is severe, a doctor may recommend treatments such as the surgical removal of your spleen or RBC transfusion.
Types of hemolytic anemia
Hemolytic anemia may be inherited (intrinsic) or acquired later in life (extrinsic).
Inherited types include:
- sickle cell anemia
- red cell membrane disorders, including hereditary spherocytosis and hereditary elliptocytosis
- pyruvate kinase deficiency
- glucose-6-phosphate dehydrogenase (G6PD) deficiency
Acquired causes of hemolytic anemia include:
Is a CBC enough to diagnose hemolytic anemia?
No. A CBC is helpful for diagnosing anemia and for providing information about the subtype you may have and its cause. Additional testing that includes other blood tests is required to make a definitive diagnosis of hemolytic anemia.
What is the most common cause of hemolytic anemia?
Sickle cell anemia is one of the most common causes of inherited hemolytic anemia. Autoimmune conditions are the most common cause of acquired hemolytic anemia.
What is the marker for autoimmune hemolytic anemia?
Doctors can detect autoimmune hemolytic anemia by the presence of autoantibodies in a direct Coombs test.
Hemolytic anemia is a subtype of anemia. A CBC is usually the first diagnostic test doctors use to diagnose this condition. If evidence of hemolytic anemia is found during a CBC, they’ll order further testing, such as haptoglobin, bilirubin, and LDH tests.