Over half the blood in your body is plasma, which is the liquid part of your blood. It is made up of water, salts, fat, sugar and proteins. Plasma is what carries blood through the body and works to transport nutrients, carbon dioxide and other waste products, antibodies, clotting proteins, chemical messengers such as hormones, and proteins that help maintain the body’s fluid balance.
Red blood cells deliver oxygen from your lungs to your tissues and organs.
White blood cells are an important part of the body’s immune system and help to protect the body from infection.
Platelets help to control bleeding by working with proteins called clotting factors.
When any one of these components of your blood doesn’t work, it can cause impaired function that can lead to many types of diseases, including cancer.
Why Do I Need So Many Blood Tests?
This is one of the most common questions we receive from patients. Blood tests can tell your doctor important information about your health. For example, a complete blood count (CBC) will indicate if your blood shows any signs of infection, immune system problems, bleeding problems, and anemia (low iron). If a blood chemistry panel is ordered, it will provide important information to your hematologist about your heart and other organs, your bones and muscles. This test also checks levels of blood sugar, calcium and other minerals in your blood and checks for levels of dehydration.
For cancer patients, hematologists/oncologists use blood tests to help diagnose cancer and monitor a patient’s blood counts and vital organs before and during their cancer treatment. Identifying specific tumor markers that can be detected in blood can aid in individualizing treatment, monitoring the status of the disease, and sometimes detect genetic abnormalities.
The Importance of Blood Tests
You might be surprised to learn how much your doctor can tell about your health from a blood test. A blood test can give information on how well your organs are functioning, such as the kidneys, liver, thyroid and heart. It can also be used to help diagnose diseases or conditions such as coronary heart disease, anemia, diabetes, HIV/AIDS and cancer. A blood test can also check to see if you have certain risk factors for heart disease. The information your doctor gets from a blood test that will show whether medicines you are taking are working and will also assess how well your blood is clotting. While doctors cannot diagnose all diseases or medical problems with just a blood test, it’s one of the single most important tests to help your doctor address any current or future health problems you may have.
Common types of blood tests that your doctor might order include:
Complete Blood Count (CBC) This blood test is the one that is most commonly ordered by doctors. By measuring the types and numbers of cells in your blood, including your red and white blood cells and platelets, this test will give your doctor a good determination of your overall health status. It can be a helpful tool in screening for disorders and evaluating your nutritional status. When you have symptoms such as fatigue, weakness and bruising, your doctor can use this test to help diagnose whether these symptoms could be a condition such as anemia, leukemia, malaria, or another type of infection.
Basic Metabolic Panel Your doctor will order this kind of blood test to measure your blood chemistry. The test measures certain compounds in your blood including glucose, sodium, potassium, calcium, chloride, carbon dioxide, blood urea nitrogen and creatinine. The test is used to monitor the effects of certain medications you are taking, such as those to prevent high blood pressure. It can also determine your blood sugar level and fluid balance, and it will tell your doctor how your kidneys are functioning. When additional testing is needed, your doctor will order a...
Comprehensive Metabolic Panel (CMP) to further evaluate organ systems and metabolic functions. The CMP measures additional proteins and substances in the blood related to liver function.
C-Reactive Protein (CRP) Test When tissues in your body are inflamed, your liver produces C-Reactive Proteins. This test measures the level of CRP present in your blood. High levels of this protein can indicate a higher risk of heart disease. CRP can be caused by a variety of things, including:
Lipid Panel This is a group of tests that can help to evaluate your risk for heart disease. It measures both cholesterol and triglyceride levels in your blood.
Hemoglobin A1C Hemoglobin is a protein in red blood cells that carry oxygen throughout the body. This test determines the body’s average blood sugar level over a period of 2-3 months by measuring what percentage of hemoglobin is coated with sugar. The test is used to measure your risk for diabetes and is also used to monitor the disease.
Thyroid Panel The thyroid panel, or thyroid function test, checks the function of the thyroid gland. It measures the amount of the thyroid-stimulating hormone (TSH) in your blood. TSH stimulates the thyroid gland to produce and release thyroid hormones into your blood. These hormones stimulate the metabolism of nearly every tissue in the body.
Prothrombin Time This test, also called PT or Pro Time, is used to measure the presence and activity of different clotting factors in the blood, and how long it takes plasma (liquid portion of the blood) to clot. It can be used to screen for bleeding abnormalities and is also used to evaluate the effectiveness of treatments using medications to prevent the formation of blood clots.
DHEA-Sulfate Serum Test This test measures the dehydroepiandrosterone (DHEA) hormone that comes from your adrenal glands. Levels that are too high or too low can be indicative of other health conditions.
Sexually-Transmitted Disease (STD) Tests Doctors can use blood tests to diagnose many types of sexually-transmitted diseases, including:
Doctors recommend that routine blood tests be done at least once a year. The risks of routine blood tests are low. Some people experience pain or discomfort from the needle puncture. Fainting from blood loss or a vein puncture can also happen. Blood tests are an important way for your doctor to determine your overall health. They can identify illness or disease in the early stages and help your doctor know how you are responding to treatments. Overall, the benefits of routine blood tests far outweigh the risks.