Leukemia Blood Tests
Blood tests are just the first step of many in diagnosing and monitoring leukemia. Your doctor orders blood tests to look for the presence of abnormalities. They also evaluate your white blood cell, red blood cell, and platelet counts.
These tests give your doctor information about leukemia type. They also help with monitoring leukemia and planning your treatment. The tests measure your body’s response to treatments so doctors know whether to adjust your care plan. Your doctor may order one or several types of blood tests depending on your needs.
Complete blood count
A complete blood count (CBC) is the first test for diagnosing and monitoring leukemia. You will likely get multiple CBC tests throughout your treatment if you have leukemia. Your results help your doctors understand if your disease is advancing or how your body is responding to treatments. They may adjust your care plan based on your results.
A CBC measures your:
- Red blood cells (RBCs or erythrocytes), which contain hemoglobin, a protein that carries oxygen to your body’s tissues
- Hematocrit, the percentage of red blood cells in your blood
- Platelets, which help your blood clot to prevent bleeding
- White blood cells (WBCs or leukocytes), which help to protect you from infections
Your doctor checks your RBCs to see if you have an appropriate number of cells per microliter (mcL) of blood. Hemoglobin measures the health of your RBCs. Hematocrit measures the mass of your RBCs as a percentage of your blood. These three tests are key components of CBC testing for red blood cell counts.
Doctors often also use a CBC with differential test. Your body creates many different types of white blood cells. A differential test measures the levels of each type. A differential test, sometimes called a white cell differential test, can help with:
- Determining blood cancer type
- Measuring how your body responds to cancer treatments such as chemotherapy
- Understanding how well your body can fight an infection
You will likely see several white blood cell measurements on your CBC results, including:
- Basophils, the cells that release heparin to prevent clots and histamine, the chemical produced during allergic reactions
- Eosinophils, the WBCs that respond to parasitic infections and cause allergic reactions
- Immature granulocytes, undeveloped basophils, eosinophils, and neutrophils
- Lymphocytes, a specific type of WBC that helps remember previous infections so your body can fight them again
- Monocytes, a WBC that helps alert other WBCs of harmful intruders such as bacteria
- Neutrophils, your WBC “first responders” that combat fungal and bacterial infections
When viewing your CBC results, it can help to know the normal ranges. You should reference your own CBC results report for ranges specific to you. In general, typical values include:
| White blood cell (WBC) | 4,000 to 10,000 cells per mcL |
| Red blood cell (RBC) | People assigned female at birth (AFAB) or those taking estrogen: 4.0 to 5.4 million cells per mcL |
| Red blood cell (RBC) | People assigned male at birth (AMAB) or those taking testosterone: 4.5 to 6.1 million cells per mcL |
| Hemoglobin (Hb) | People AFAB or those taking estrogen: 11.5 to 15.5 grams per deciliter (g/dL) |
| Hemoglobin (Hb) | People AMAB or those taking testosterone: 13 to 17 g/dL |
| Hematocrit (Hct) | People AFAB or those taking estrogen: 36% to 48% |
| Hematocrit (Hct) | People AMAB or those taking testosterone: 40% to 55% |
| Platelet count | 150,000 to 400,000 cells per mcL |
| Lymphocytes | 1,000 to 4,800 per mcL |
| Monocytes | 200 to 800 per mcL |
| Immature granulocytes | < 100 per mcL |
| Basophils | < 300 per mcL |
| Eosinophils | < 500 per mcL |
| Neutrophils | 2,500 to 7,000 per mcL |
All of these measurements give your doctor a picture of your overall health. Typical ranges can vary based on several factors, including:
- Age
- The lab and what units of measurement they use
- Whether you have underlying health conditions or are pregnant
- Your typical hormone levels
If you have leukemia, you may have low levels of healthy blood cells or high levels of irregular blood cells.
CBC Report: What it means
During leukemia treatment, CBC results may show:
Low RBC, hematocrit, or hemoglobin counts
Low red blood cell levels indicate anemia. Your red blood cells contain hemoglobin and iron, which carry oxygen from the lungs to the rest of your body. Sometimes, low iron levels cause anemia. Other times, you develop anemia because a disease is destroying your red blood cells.
Your doctor may recommend a reticulocyte count if you have a low RBC count. This blood test helps identify why the RBC count is low.
High RBC counts
High red blood cell levels are called erythrocytosis, which can lead to blood clotting. You may need treatments to reduce your levels if you have a high RBC count.
Low platelet counts
A low platelet count is called thrombocytopenia. It may cause you to bruise or bleed easily.
High platelet counts
Doctors diagnose high platelet counts as thrombocytosis. High platelet levels increase your risk of a blood clot, heart attack, or stroke.
Low white blood cell counts
A low white blood cell count is called leukopenia. Your body has a harder time fighting infections when you have leukopenia. You can develop leukopenia because of leukemia itself or because of leukemia treatments.
Your doctor will also look at your levels of specific types of white blood cells:
- Low neutrophils are called neutropenia. In neutropenia, you have a higher risk of getting an infection. Illnesses can also last longer or be more difficult to treat.
- Low lymphocytes cause your body to have a harder time identifying or fighting infections. Lymphocytes create an immune response after they’re exposed to new foreign substances called antigens.
High white blood cell counts
A high white blood cell count is called leukocytosis. It’s a common characteristic of leukemia.
People with leukemia may also have:
- High neutrophils are called neutrophilia. You may get recurring infections or fevers.
- High lymphocytes are known as lymphocytosis. Lymphocytes are a specific type of white blood cell that help fight infections.
Your doctor may monitor your white blood cell levels throughout leukemia treatment. The results help them know whether treatment is effective.
Pancytopenia
Pancytopenia is when your red blood cell, white blood cell, and platelet counts are all low. Both leukemia and leukemia treatments, such as chemotherapy or radiation therapy, can cause it.
Peripheral blood smear
You may get a blood smear with your CBC. A blood smear is a drop of blood on a slide that a pathologist (doctor specializing in analyzing body fluids and tissues) examines under a microscope. It provides more information about the appearance of your blood cells and can further help in your diagnosis. Your doctor may also use these tests to monitor your blood cells during cancer treatment.
Flow cytometry
Flow cytometry helps doctors diagnose and monitor blood cancer and is important in analyzing certain cell properties. Your provider takes cells from a blood or bone marrow sample and treats them with a fluorescently stained antibody. The fluorescent stain allows laser technology to evaluate the cells. For example, it may look for whether you have specific protein markers (antigens) on the surface of your cells.
Doctors may also order a flow cytometry test after you complete cancer treatment to check for minimal residual disease (MRD). MRD refers to how many cancer cells you still have in your body. The test will help your care team determine if you need additional treatment.
Helpful resources
Support can make a big difference when facing a leukemia diagnosis. Connect with others through our peer support programs or browse our directory of resources for patients, families, and caregivers.
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