Blood Test
Types of blood tests
Blood tests are very common. They help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working.
Complete blood count (CBC)
The complete blood count (CBC) is one of the most common blood tests. It is often done as part of a routine checkup. This test measures many different parts of your blood, including red blood cells, white blood cells, and platelets.
- Red blood cell levels that are higher or lower than normal could be a sign of dehydration, anemia, or bleeding. Red blood cells carry oxygen from your lungs to the rest of your body.
- White blood cell levels that are higher or lower than normal could be a sign of infection, blood cancer, or an immune system disorder. White blood cells are part of your immune system, which fights infections and diseases.
- Platelet levels that are higher or lower than normal may be a sign of a clotting disorder or a bleeding disorder. Platelets are blood cell fragments that help your blood clot. They stick together to seal cuts or breaks on blood vessel walls and stop bleeding.
- Hemoglobin levels that are lower than normal may be a sign of anemia, sickle cell disease, or thalassemia. Hemoglobin is an iron-rich protein in red blood cells that carries oxygen.
- Hematocrit levels that are too high might mean you’re dehydrated. Low hematocrit levels may be a sign of anemia. Hematocrit is a measure of how much space red blood cells take up in your blood.
- Mean corpuscular volume (MCV) levels that are lower than normal may be a sign of anemia or thalassemia. MCV is a measure of the average size of your red blood cells.
The table below shows some normal adult ranges for different parts of the CBC test. Some of the normal ranges differ between men and women. Other factors, such as age, high altitude, and race, also may affect normal ranges.
Your healthcare provider should discuss your results with you. They will advise you further if your results are outside the normal range for your group.
| Test | Normal Range Results* |
|---|---|
| Red blood cell | Adult Men: 5 to 6 million cells/mcL Adult Women: 4 to 5 million cells/mcL |
| White blood cell | 4,500 to 10,000 cells/mcL |
| Platelets | 140,000 to 450,000 cells/mcL |
| Hemoglobin (varies with altitude) | Adult Men: 14 to 17 gm/dL Adult Women:12 to 15 gm/dL |
| Hematocrit (varies with altitude) | Adult Men: 41% to 50 % Adult Women: 36% to 44% |
| Mean corpuscular volume | 0 to 95 femtoliter† |
* Cells/mcL = cells per microliter; gm/dL = grams per deciliter.
† A femtoliter is a measure of volume.
Blood chemistry tests/basic metabolic panel
The basic metabolic panel (BMP) is a group of tests that measures different naturally occurring chemicals in the blood. These tests usually are done on the fluid (plasma) part of blood. The tests can give providers information about your organs, such as the heart, kidneys, and liver.
The BMP includes blood glucose, calcium, and electrolyte tests, as well as blood tests that measure kidney function. Some of these tests require you to fast (not eat any food) before the test, and others don’t. Your provider will tell you how to prepare for the test(s) you’re having.
Blood enzyme tests
Blood enzyme tests may be used to check for heart attack. Enzymes are chemicals that help control chemical reactions in your body. There are many types of blood enzyme tests. The ones for heart attack include troponin and creatine kinase (CK) tests.
Blood levels of troponin go up when a person has muscle damage, including damage to the heart muscle. In addition, an enzyme called CK-MB is released into the blood when the heart muscle is damaged. High levels of CK-MB in the blood can mean that you’ve had a heart attack.
Lipoprotein panel
A lipoprotein panel, also called a lipid panel or lipid profile, measures the levels of LDL and HDL cholesterol and triglycerides in your blood. Cholesterol and triglyceride levels that are higher or lower than normal may be signs of higher risk of coronary heart disease.
A lipoprotein panel gives information about your:
- Total cholesterol
- LDL (“bad”) cholesterol, which is the main source of cholesterol buildup and blockages in the arteries
- HDL (“good”) cholesterol, which helps decrease cholesterol blockages in the arteries
- Triglycerides, which are a type of fat in your blood
Most people will need to fast for 9 to 12 hours before a lipoprotein panel.
Blood clotting tests
Blood clotting tests are sometimes called a coagulation panel. These tests check proteins in your blood that affect the blood clotting process. Levels that are higher or lower than normal might suggest that you’re at risk of bleeding or developing clots in your blood vessels.
Blood clotting tests also are used to monitor people who are taking medicines to lower the risk of blood clots. Warfarin and heparin are two examples of such medicines.
Bone marrow tests
Bone marrow tests check whether your bone marrow is healthy and making normal amounts of blood cells. The two bone marrow tests are aspiration and biopsy.
- Aspiration collects a small amount of bone marrow fluid through a larger needle.
- Biopsy tests are often done at the same time as the aspiration test. A biopsy test collects a small amount of bone marrow tissue through a larger needle.
These tests can help find the cause of low or high blood cell counts. They also play an important role in checking how well treatments for certain types of cancers, such as leukemia or lymphoma, are working.
Before this procedure, be sure to tell your provider about current medicines you are taking, known allergies to medicines, if you are pregnant, or if you have a bleeding disorder.
Bone marrow tests can be done in a hospital or doctor’s office or clinic. You may be awake for your test and may be given medicine to relax you during the test. You may also be under anesthesia for this test, if recommended by your care team. You will lie on your side or stomach or back, depending on where your provider obtains the samples from. Your provider will clean and numb the top ridge of the hipbone or rib bone, where the needle will be inserted. You may feel a brief, sharp pain when the needle is inserted and when the bone marrow is aspirated. The bone marrow samples will be studied in a laboratory.
After your test, you will have a small bandage on the site where the needle was inserted. Most people go home the same day. You will need a ride home if you received medicines to relax you during the test. You may have mild discomfort but likely won’t have any pain after the test. Your doctor may have you take an over-the-counter pain medicine. Call your provider if you are in serious pain or if you develop symptoms including:
- Fever
- Redness
- Swelling
- Discharge at the needle injection site