Colonial Heights Medical Center Hopewell Medical Center
(804) 520-1110 (804) 458-8557
Understanding Your Lab Results
While there are thousands of laboratory tests that can be ordered by your health care provider, the vast majority of lab tests are fairly routine tests ordered many times a week for patients with all sorts of medical problems. These common blood tests are the most likely you will encounter. Below we have listed a few of the more common tests with an explanation of what the various numbers mean. Some of the lab tests that we order consist of only one test. But many of the lab tests that we order come as part of a lab "panel". This panel is a convenient way for providers to order multiple lab tests that are commonly ordered together. For example, you may here a provider mention your "CBC". This is not actually a lab test, but a collection of many lab tests including a white blood count, hemoglobin, platelet count, and multiple other tests providing more detailed information about your blood cells.
COMMON LAB TESTS/LAB PANELS:
CBC (Complete Blood Count)
WBC (white blood count) - these are the cells that fight infections. Elevated numbers are usually related to infection. Patients on prednisone (a type of steroid) may also see elevation of their white blood count. There are 5 subsets of WBC's on the blood count with each type affected by different medical conditions. Hgb (hemoglobin) - This is the number that is used when we talk about anemia. People that are low in hemoglobin have less ability to carry oxygen in the blood. There are many reasons that it may be low including blood loss, iron losses, heavy periods in women, and some medical diseases. Platelets - These are the small particles in the blood that are used to help build clots in injured blood vessels. When you have a cut, your body uses these and other things to "plug the hole".
MCV (mean corpuscular volume) - This test indicates the average size of your red blood cells. The blood cells will tend to be small in patients that have low iron. They tend to be too large in patients that drink excessive amounts of alcohol or patients that are low in Vitamin B12.
BMP (Basic Metabolic Panel)
Na (sodium level) K (potassium level) - may be decreased by diarrhea or diuretic blood pressure medications. Having low potassium levels commonly causes muscle cramps. High levels can be caused by some blood pressure medications, excessive potassium intake, or kidneys that are not working properly. Cl (chloride) CO2 (carbon dioxide, bicarbonate) Ca (calcium) Glucose - your blood sugar. Elevated levels may indicate diabetes if taken when you have not eaten or had anything to drink. Typical fasting levels range from 65-109. Fasting levels between 110 and 125 may indicate some problems with the way your body handles sugar, but is not in the range considered to be diabetes. This is commonly referred to as glucose intolerance, or pre-diabetes. Levels greater than 125 may indicate diabetes, formally called diabetes mellitus. BUN (blood urea nitrogen) Cr (Creatinine) Both BUN and creatinine are products that are filtered out normally by the kidneys. Increased levels may indicate kidneys that are temporarily not working properly or chronic kidney problems.
This panel includes a list of tests that tell us about the functioning of the liver. ALT (Alanine Aminotransferase) - an enzyme of the liver cells that becomes elevated with inflammation in the liver. Typically, this and the AST are the main numbers that we look at in monitoring for irritation to the liver from medications, especially "statin" medications used to treat elevated cholesterol. AST (Aspartate Aminotransferase) - an enzyme of the liver (see ALT above), but some also found in muscle, heart, and other organs. ALP (Alkaline Phosphatase) - an enzyme found in the liver, bones and intestines. While growing children may have higher levels due to bone growth, adults with elevated levels raise concerns for bone disease or blocked bile ducts. Bili (bilirubin) - may be broken into "direct" and "total" bilirubin. This is a breakdown product of red blood cells in the body. The liver processes bilirubin so that it can be eliminated from the body. The "total" bilirubin is the portion that the liver has already processed. Blocked bile ducts may prevent excretion from the body causing levels to rise. Albumin/Protein - these are some of the building products for the body. The liver is responsible for making proteins and damage to the liver may decrease levels. However, these levels may also decrease if kidney diseases or other medical problems are causing the body to lose protein.
Lipids (Cholesterol Panel)*
Total Cholesterol - this number represents the sum of all the different types of cholesterol in the blood. The goal for total cholesterol is most commonly to be less than 200. HDL (high density lipoprotein) - this is typically thought of as your "good" cholesterol that helps to clean your arteries/prevent plaque build-up. The goal is for men to have numbers >40, while women should be >50. There is a strong genetic component to cholesterol and people have HDL numbers ranging from <20 to >100. The important thing is to try to get it as high as you can. Some medications can help raise the HDL, but regular aerobic exercise, 30-45 minutes daily, can also have a positive effect on your HDL. LDL (low density lipoprotein) - this is your "bad" cholesterol that contributes to plaque build-up in your arteries. There are different goals depending on your medical history, but generally health care providers strive to get your LDL <100. Patients with diabetes and known heart disease, or heart attack victims may try to set a lower goal of <70. A low fat/low cholesterol diet, as recommended by the American Heart Association can help lower your cholesterol. For a list of foods that are generally higher or lower in cholesterol, ask your health care provider. TG (triglycerides) - This is a part of your cholesterol levels that represents the fats that are in your blood. The goal is to have triglyceride levels <150. A low fat diet can help lower your triglycerides. Fish Oils (omega-3 fatty acids), have been shown to help lower triglyceride levels, and may also help raise your HDL slightly.
*There are other tests that can further breakdown your cholesterol numbers to subsets of HDL1, HDL2, HDL3, and apo/lipo-proteins, but these are not common tests and are usually reserved for special situations. If you have questions about these tests or other less common tests as markers of potential cardiac disease, such as CRP levels, please ask your health care provider.
TSH (thyroid stimulating hormone) - this is usually the first test a provider will check to see if you have thyroid problems. This hormone is secreted by the pituitary gland in the brain to tell the thyroid gland (located in the lower front portion of your neck) to make thyroid hormone. If your TSH level is elevated, it usually indicates that your thyroid hormone in your body is too low. If your TSH is low, it usually indicates that you have too much thyroid hormone, though in rare cases it can be an indication of a pituitary problem as well. When adjusting thyroid medications it is often confusing to patients that a low TSH requires less thyroid medication, while a high TSH requires more medication. Just remember that the TSH is not your thyroid level, but usually moves in the reverse direction as your thyroid level.
*In most cases, high TSH = low thyroid, low TSH = high thyroid
T4 level (thyroxine) - this is thyroid hormone. You may have a "freeT4" which is the active, useful portion in your body, or a "total T4", which includes the active and the stored T4 in your body. Each has there own normal ranges.
HgbA1C (hemoglobin A1C, glycosolated hemoglobin)
HgbA1C - indicates the average amount of sugar in your blood over roughly the past three months. Diabetics check their blood sugar anywhere from a couple of times a week to several times daily depending on medications and severity of disease. But figuring out how you are doing over several months is difficult to determine from looking at the wide fluctuations in numbers before and after eating. This test allows you to see significant changes of as little as 3-4 points. The goal for this number depends on multiple factors, but it is generally considered that a level of <6.5% for a diabetic is good control. Some patient's goals may be anywhere from a low of 6% for aggressive therapy, to 7% for less aggressive control. A change of 0.1% in your HgbA1C indicates a rise or drop in your average blood sugar of about 3-4 points over the past 3 months.
PSA (prostate specific antigen)
PSA - This is a protein made by the prostate gland. It is used to monitor for signs of prostate cancer. The level in your blood reflects how much is being made in your prostate. Typical levels in the blood are about 0.6-1.0, but these levels normally rise as you get older. While elevated levels may indicate prostate cancer, it is important to know that BPH (benign prostatic hypertrophy, "enlarged" prostate) can raise levels, as well as infection in the prostate, or "prostatitis". Labs usually list levels of <4.0 as normal, but younger men should have levels <2.5, and older men may have normal levels >5.0. The trend of your numbers over time is also important as a rising PSA of >0.7 per year is also reason for concern. Your provider can explain your numbers in relation to your age and medical conditions.