Blood Cells
Your complete blood count: red cells that carry oxygen, white cells that fight infection, and platelets that clot.
47 tests explained
Most common tests
- Basophils (Absolute)The number of basophils, the rarest white blood cell, in each microliter of your blood. Basophils take part in allergic reactions.
- Basophils (Percent)The share of your white blood cells that are basophils, the rarest white cell type, which takes part in allergic reactions.
- Eosinophils (Absolute)The number of eosinophils, white blood cells that take part in allergies and fight some parasites, in each microliter of your blood.
- Eosinophils (Percent)The share of your white blood cells that are eosinophils, a cell type involved in allergies and in fighting some parasites.
- HematocritThe share of your blood made up of red blood cells, shown as a percent. It usually moves together with hemoglobin.
- HemoglobinThe oxygen-carrying protein in your red blood cells. It is the main number used to check for anemia.
- Lymphocytes (Absolute)The actual number of lymphocytes, immune cells that help fight viruses and remember germs, in a given amount of blood.
- Lymphocytes (Percent)The share of your white blood cells that are lymphocytes, immune cells that help fight viruses, shown as a percent.
- Mean Corpuscular Hemoglobin (MCH)How much hemoglobin, on average, each of your red blood cells carries.
- Mean Corpuscular Hemoglobin Concentration (MCHC)How concentrated the hemoglobin is inside your red blood cells, which shows how pale or dense they are.
- Mean Corpuscular Volume (MCV)The average size of your red blood cells. It helps show whether they run smaller or larger than usual.
- Mean Platelet Volume (MPV)The average size of your platelets, the small blood cells that help your blood clot.
- Monocytes (Absolute)The number of monocytes in a microliter of blood. Monocytes are white blood cells that clear debris and help fight infection.
- Monocytes (Percent)The share of your white blood cells that are monocytes. The absolute monocyte count is usually the more useful number.
- Neutrophils (Absolute)The number of neutrophils in a microliter of blood. Neutrophils are your most common white blood cell and a first line of defense against germs.
- Neutrophils (Percent)The share of your white blood cells that are neutrophils. The absolute neutrophil count is usually the more useful number.
- Platelet CountThe number of platelets, the small blood cells that help your blood clot, in a sample of your blood.
- Red Blood Cell CountThe number of red blood cells in a sample of your blood. These cells carry oxygen from your lungs to the rest of your body.
- Red Cell Distribution Width (RDW-CV)How much your red blood cells vary in size. A higher number means a wider mix of small and large cells.
- White Blood Cell CountThe total number of white blood cells, the immune cells that fight infection, in a small sample of your blood.
Common follow-up tests
- Atypical (Reactive) Lymphocytes (Absolute)The number of 'activated-looking' (atypical or reactive) lymphocytes in a volume of blood, usually worked out from the percent and your total white cell count.
- Atypical (Reactive) Lymphocytes (Percent)The share of your white blood cells that are lymphocytes with an 'activated' look under the microscope, most often because your immune system is responding to a virus.
- Band Neutrophils (Absolute)The number of band neutrophils (young neutrophils) in a volume of blood, usually worked out from the band percent and your total white cell count.
- Band Neutrophils (Percent)The share of your white blood cells that are band neutrophils, young neutrophils released early when the body is fighting an infection or inflammation.
- Direct Antiglobulin Test (Direct Coombs)A blood-bank test that checks whether antibodies or complement proteins are stuck to the surface of your red blood cells.
- Erythropoietin (EPO)A hormone made mostly by the kidneys that tells the bone marrow to make red blood cells. It is read alongside your hemoglobin.
- G6PD (Glucose-6-Phosphate Dehydrogenase)Measures how active the G6PD enzyme is in your red blood cells. Low activity is called G6PD deficiency.
- HaptoglobinA protein made by the liver that binds free hemoglobin. A low level can be a clue that red blood cells are breaking down faster than normal.
- Hemoglobin A2 (HbA2)The share of your hemoglobin that is the minor form HbA2. It helps clinicians sort out inherited hemoglobin conditions such as beta-thalassemia trait.
- Hemoglobin Electrophoresis InterpretationA written summary of your hemoglobin test pattern that names the types of hemoglobin found, such as a normal pattern or a carrier state.
- Hemoglobin F (Fetal Hemoglobin)The share of your hemoglobin that is the fetal type, HbF. It is high in newborns and falls to a very low level after the first two years.
- Hemoglobin S (HbS)How much of your hemoglobin is the sickle type, HbS. Most people have none. A result above zero needs the full hemoglobin report to interpret.
- Immature Granulocytes (Absolute)The number of young white blood cells (immature granulocytes) in a microliter of blood. Most healthy adults have very few.
- Immature Granulocytes (Percent)The share of your white blood cells that are young, not-yet-mature granulocytes. Clinicians read it with the rest of your CBC.
- Nucleated Red Blood Cells (nRBC) (Absolute)The number of nucleated red blood cells in each microliter of blood. Healthy people usually have none after the first weeks of life.
- Nucleated Red Blood Cells (nRBC) (Percent)How many nucleated red blood cells are in the blood for every 100 white blood cells. Healthy people usually have none after the first weeks of life.
- Peripheral Blood Smear InterpretationA written description of how your blood cells look under a microscope. Labs add it when a CBC result needs a closer look.
- Platelet Distribution Width (PDW)A measure of how much the sizes of your platelets vary. It is a minor extra on some blood counts, and analyzers report it on different scales.
- Platelet Estimate (Smear)A quick check of how many platelets are on a blood smear, reported as decreased, adequate or increased. It double-checks the machine's count.
- Platelet MorphologyA written description of how your platelets look under the microscope, such as size, color and clumping.
- RBC MorphologyA written description of how your red blood cells look under a microscope: their size, color, shape and any unusual features.
- Red Cell Distribution Width (RDW-SD)How wide the spread of red blood cell sizes is, in femtoliters (fL). A higher number means a wider mix of small and large cells.
- Reticulocyte Count (Absolute)The number of reticulocytes (very young red blood cells) in a set amount of blood. It shows how many new red cells your bone marrow is releasing.
- Reticulocyte Count (Percent)The share of your red blood cells that are brand new. It shows how actively your bone marrow is making red cells.
- Reticulocyte Hemoglobin Content (CHr / Ret-He)How much hemoglobin is in your newest red blood cells, in picograms (pg). It reflects the iron available to your bone marrow over the last few days.
- Sickle Cell Screen (Hemoglobin S Solubility)A quick check for hemoglobin S, the type of hemoglobin linked to sickle cell trait and sickle cell disease. It can't tell the two apart.
- WBC MorphologyA written description of how your white blood cells look under a microscope, such as their shape, granules and any immature cells.