Take Charge of Your Health - Blood Testing 101
Having routine blood work is an important and remarkably easy way to learn about your overall health. The benefits of blood testing include: information on how your body is functioning; determining your risk of disease or medical conditions; early diagnosis before severe symptoms or complications develop; monitoring the success of treatments; identifying the side effects of treatment for better management; and monitoring the status of chronic disease.
Blood tests or what we often refer to as “lab work” are typically ordered by your primary care physician at an annual exam, but testing may be needed more frequently depending on your health status. These tests generally take less than five minutes and you can resume your normal activities immediately.
There are three main types of blood tests: a complete blood count (CBC), a comprehensive metabolic panel (CMP), and a lipid panel. Each of these test for different things. A complete blood count (CBC) is a blood test that helps healthcare providers screen for and detect a range of disorders and medical conditions. It can also help identify medication side effects so treatments can be adjusted if necessary. A CBC also includes a range of subtests to measure and study our white blood cells, red blood cells, and platelets. White blood cells are linked to our immune system and help our body fight infection; red blood cells carry oxygen throughout the body; and platelets help our blood clot. CBC subtests help measure, count, and evaluate the various elements of our blood. The tests inform the physician of how many new blood cells your body is creating, the sheer number of red and white cells and platelets, and the size and shape of the cells. This can help your healthcare provider diagnose conditions such as anemia, infections, certain types of cancer, the side effects of treatment such as chemotherapy or prescription drugs, and vitamin/mineral deficiencies.
The White Blood Cell (WBC) count subtest can reveal insights into the immune system. A high white blood cell count can indicate infection, while a low count can point towards HIV, leukemia, hepatitis, or arthritis. The Red Blood Cell (RBC) count estimates the volume of RBCs within the individual and is useful in diagnosing anemia.
Other examples of CBC subtests are:
CBC without differential counts the total number of white blood cells
CBC with differential studies the five kinds of white blood cells and reports on how many of each kind of white blood cell you have
Hematocrit describes the concentration of red blood cells in your blood
Hemoglobin is a protein contained within RBCs that sends oxygen from the lungs to body tissue. This test measures the hemoglobin protein in the red blood cells.
Platelet count: Platelets are small cells that help the blood to clot. A high count can indicate anemia, cancer, or infection, while a low count can prevent wounds from healing and result in bleeding. Source: Cleveland Clinic
The second type of test is the comprehensive metabolic panel (CMP). This blood test measures 14 different substances in the blood. It provides important information about your body's chemical balance and metabolism, and like a CBC, physicians use the CMP to help screen for, diagnose, and monitor health conditions. Specifically the CMP is helpful to examine liver and kidney health, blood sugar levels, the acid and base balance in the blood, and your fluid/electrolyte balance.
A CMP measures:
Glucose: A type of sugar that provides energy for your body and brain and links to diabetes
Calcium: A vital mineral in both your bones and blood, essential to the functioning of your heart, nerves, and muscles
Total protein: A measurement of the total amount of proteins (albumin and globulins) in your blood
Bilirubin: A waste product from the breakdown of red blood cells which is removed by your liver
BUN (blood urea nitrogen): A measurement of urea nitrogen which is a waste product removed by the kidneys
Creatinine: A byproduct of muscle activity that the kidneys filter and remove
Albumin: A protein that transports important substances through your bloodstream
4 Electrolytes (sodium, potassium, chloride, and bicarbonate). Electrolytes control nerve and muscle function and maintain the pH balance of our blood as well as our water balance.
3 Liver enzymes: Alkaline phosphatase (ALP), Alanine transaminase (ALT), and Aspartate aminotransferase (AST).
In addition, the CMP can also includes these calculated measurements: BUN/Creatinine Ratio; Albumin/Globulin Ratio; and Globulin. A basic metabolic panel (BMP) includes eight of the 14 tests in the CMP. A BMP does not include the liver enzyme and protein tests.
The third type of testing bundle is a lipid panel, which measures the amount of fat molecules in the blood, specifically four cholesterol measurements and one for triglycerides. Having too many of these lipids (fat molecules) is linked to cardiovascular disease, heart attack, and stroke.
The five types of lipids studied in the blood sample are:
Low-density lipoprotein (LDL) cholesterol: “Bad cholesterol” that can collect in your blood vessels and increase the risk of cardiovascular conditions
Very low-density lipoprotein (VLDL) cholesterol: This cholesterol is usually found in very low amounts due to fasting, but an increase may be a sign of abnormal lipid metabolism.
High-density lipoprotein (HDL) cholesterol: “Good cholesterol” which helps decrease the buildup of LDL in blood vessels
Total cholesterol: Overall cholesterol level, which is the combination of LDL-C, VLDL-C, and HDL-C
Triglycerides: A type of fat from the food we eat, which can be associated with cardiovascular disease and inflammation of the pancreas.
If you have abnormal lipid panel results, your healthcare provider will likely recommend lifestyle
changes such as a healthy diet and exercise plan or a cholesterol-lowering medication. Generally the recommendation is made to continue to monitor the lipids in your blood.
In summary, a little bit of blood goes a long way. Blood testing can:
Find health problems in their early stages
Help determine how well organs such as your kidneys, liver, heart, or thyroid are working
Help diagnose diseases such as cancer, diabetes, coronary heart disease, and anemia
Diagnose bleeding or clotting disorders
Help determine if your immune system is having trouble fighting infections
Monitor the progress or setbacks of chronic health conditions
Find out if your medicine and/or treatment plan is effective
In terms of preparation for your blood testing, be sure to ask about fasting, which is typically 10-12 hours before the blood draw. If fasting is required, try to schedule your blood testing for early morning so you do not have to miss several meals as nothing but water is allowed while fasting. If you break the fast, be sure to call your doctor and reschedule the testing.
Remember not all medical offices have the same protocols for getting back to you with your test results so be sure to ask when the test results will be available and how best to access them.