Blood Test Results Guide
You and your doctor can learn a great deal about your health through a simple screening procedure known as Complete Blood Count (CBC).
The following is a brief description of the tests that are included in a Complete Blood Count. The descriptions will help you better understand your laboratory test results. You should not rely on this information for diagnostic treatment. These descriptions are not intended to be a complete listing of all conditions medically relevant to each test. Always consult your medical provider regarding your laboratory tests.
The CBC is one of the most commonly ordered blood screening tests and is used to present a general picture of a person’s overall health. It is used to help diagnosis disease when people are “not feeling well” and to monitor treatment of many disease states, including anemia and leukemia. In the CBC, the different types of cells in the blood are counted and examined by a machine.
A normal test is just as significant as an abnormal result. When a result is normal, it helps rule out disease, and also establishes a baseline for you. Each person has his or her own baseline “normal.” A person’s own result is the best baseline or monitoring any change that takes place in the future. A 12 hour fast is recommended for chemistry testing as the glucose, cholesterol and triglyceride may be high if you are non fasting.
Electrolytes are substances that become ions in solution and acquire the capacity to conduct electricity. The balance of the electrolytes in our bodies is essential for normal function of our cells and our organs.
Sodium: (Na) Sodium is the major positive ions found outside the cells. Excess sodium is excreted in the urine. Sodium regulates the total amount of water in the body and the transmission of sodium into and out of individual cells also plays a role in critical body functions. Many processes in the body, especially in the brain, nervous system, and muscles, require electrical signals for communication. A low level can be caused by the loss of sodium in diarrhea, urine, or vomiting. A high level can be caused by an excessive intake of salt or an insufficient intake of water.
Potassium: (K) Potassium is the major positive ion found inside the cells. The proper level of potassium is essential for normal cell function. Among the many functions of potassium in the body is regulation of the heartbeat and function of the muscles. A low level can cause muscle weakness and heart problems. A high level can be found in kidney disease or in overuse of potassium supplements.
Chloride: (Cl) Chloride is the major negatively charged ion found in the fluid outside of cells and in blood. Chloride plays a role in helping the body maintain a normal balance of fluids. Increased chloride may be seen in diarrhea, certain kidney diseases, and sometimes in over active parathyroid glands. Chloride is normally lost in the urine, sweat, and stomach secretions. Excessive loss can occur from heavy sweating, vomiting, and adrenal gland and kidney disease.
Cholesterol: Cholesterol is an essential blood fat found in nearly every body tissue. It is a waxy, fat like substance that occurs naturally in all parts of the body. Cholesterol is made in the liver and moves through the bloodstream to your body’s cells in special carriers called lipoproteins. Your body need cholesterol to work normally, and it makes all it needs. Too much cholesterol in the blood increases the risk of fatty buildups in the arteries and increases the risks of heart attach and stroke.
HDL Cholesterol: High density lipoprotein (HDL) cholesterol is one of several types of fats and is measured as “total Cholesterol”. It is referred to as “good” cholesterol because it acts as a scavenger, removing excess cholesterol from artery walls. It has been shown that the higher the level of HDL cholesterol, the lower the risk of developing heart disease. HDL can be increased by aerobic exercise that raises your heart rate for 20 to 30 minutes at a time, lose weight – (obesity increases LDL cholesterol but also reduces HDL), stop smoking, cut out trans fatty acids and add monounsaturated fats and add soluble fiber to your diet.
LDL Cholesterol: Low density cholesterol is sometimes called the “bad” cholesterol. When too much LDL circulates in the blood, it can slowly build up in the inner walls of the arteries that feed the heart and brain. Together with other substances, it can form plaque, a thick, hard deposit that can narrow the arteries and make them less flexible. This is known as atherosclerosis. If a clot forms and blocks a narrowed artery, heart attack or stroke can result. LDL cholesterol can be lowered by healthy eating, exercise and medication.
VLDL Cholesterol: Very low density lipoprotein cholesterol is one of the three major types of blood cholesterol combined with protein. VLDL cholesterol contains the highest amount of triglyceride. As triglyceride levels are reduced, so are VLDL levels. Foods that are high in glycemic index tend to stimulate VLDL production.
Triglycerides: Triglycerides are a fatty substance in the body which acts as a major form of stored energy. Too much of this type of fat can contribute to the hardening and narrowing of your arteries. This puts you at risk for having a heart attack or stroke. Diseases such as diabetes, obesity, kidney failure or alcoholism can cause high triglycerides. You must not eat for at least 12 hours to obtain an accurate result for this test. Low values are not generally considered significant.
Cardiac Risk Factor: Factors that increase your risk for coronary artery disease include some you can’t control and several that you can. You can’t control your age, gender, race, family medical history or heart conditions you may have had previously. You can control, treat, or prevent the following risks:
- Cigarette smoking and tobacco smoke
- High blood cholesterol
- High blood pressure
- Physical inactivity
- Overweight or obesity
The purpose of this test is to determine the ratio of plasma (clear liquid part of the blood) to red cells in the blood or in short, hematocrit measures how much of your blood is made of red cells. The measurement is useful in identifying anemia, the presence of liver disease and red cell production within the circulatory system.
Hemoglobin is a protein molecule in the red blood cells that carries oxygen from the lungs to the body’s tissues and returns carbon dioxide for the tissues to the lungs. The oxygen is used by the cells to produce energy, and carbon dioxide is the waste product of the energy production process. The measurement of hemoglobin gives an exact picture of the ability of the blood to carry oxygen. People with a low hemoglobin level have anemia and usually have a low RBC and low hematocrit. There are many reasons for anemia, loss of blood, (traumatic injury and surgery), nutritional deficiencies, (iron, vitamin B12 and folate), bone marrow problems (suppression of chemotherapy drugs and kidney disease) and abnormal hemoglobin (sickle cell anemia). Higher than normal hemoglobin can be seen in people at high altitudes and in smokers. Dehydration produces falsely high hemoglobin which disappears when proper fluid balance is restored. Some infrequently causes are lung disease, certain tumors, a disorder of the bone marrow and abuse of the drug erythropoietin by athletes for blood doping purposes.
Red blood cells’ indices are measurements that describe the size and oxygen-carrying protein (hemoglobin) content of red blood cells. The indices are used to help in the differential diagnosis of anemia.
MCV (mean cell volume) measures the average size of red blood cells.
MCH (mean cell hemoglobin) reflects the average weight of hemoglobin found in the red blood cells. MCH values usually rise or fall as the MCV increased or decreased.
MCHC (mean cell hemoglobin concentration) reflects the average amount of hemoglobin in the red blood cells. As MCV relates the size of the cells, MCHC relates to the color of the cells.
RDW (red cell distribution width) measures the variation of size of the red blood cells. Usually RBCs are a standard size, certain disorders, however, causes a significant variation of cell size.
HDW (hemoglobin distribution width) is used to differentiate some anemia states.
Creatinine: Creatinine is a waste product in the blood created by the normal breakdown of muscle cells during activity. Healthy kidneys take creatinine out of the blood and put into the urine to leave the body. When kidneys are not working well creatinine builds up in the blood.
Blood Urea Nitrogen: (BUN) Blood urea nitrogen measures the amount of urea nitrogen, a waste product of protein metabolism in the blood. Urea is formed by the liver and carried by the blood to the kidneys for excretion. When your kidneys are not working well, the level of BUN in the blood will rise. Dehydration, blood loss, high protein diets and/or strenuous exercise can cause a high BUN level. A low BUN level may be the result of liver disease, a low protein diet, or drinking to much water.
BUN/Creatinine Ratio: (B/C Ratio) By comparing the BUN level in the blood to the creatinine level, the doctor can determine if the high BUN level is caused by kidney disease, dehydration or gastrointestinal bleeding.
Proteins are the most abundant compounds in your serum. Amino acids are the building blocks of all proteins and proteins are the building blocks of all cells and body tissues. Proteins are the basic component for enzymes, many hormones, antibodies and clotting agents. Proteins play a major role in maintaining the delicate acid-alkaline balance of your blood.
Total Proteins: Total protein is a measure of all the proteins found in the fluid portion of your blood. Specifically, it looks at the total amount of 2 classes of protein, albumin and globulin. This test is often done to diagnosis nutritional problems, kidney disease or liver disease. Higher than normal levels may be due to chronic inflammation or infection, dehydration, respiratory distress and multiple myeloma. Lower than normal levels may be due to diarrhea, severe burns, liver disease, malabsorption and malnutrition.
Albumin: Albumin is the protein of the highest concentration in plasma. Albumin transport many small molecules in the blood (bilirubin, calcium, progesterone and drugs.) It is also of prime importance keeping the fluid from the blood from leaking out into the tissues. Albumin is made by the liver and decreased serum albumin may result from liver disease. It can also result from kidney disease, which allows albumin to escape into the urine. Decreased albumin may be explained by malnutrition or a low protein diet.
Globulin: Globulins are proteins that include gamma globulins (antibodies) and a variety of enzymes and carrier/transport proteins. The specific profile of globulins is determined by protein electrophoresis which separates the protein according to size and charge. Increased levels may be seen in chronic infections, liver disease, rheumatoid arthritis, multiple myeloma and autoimmunity. Decreased levels may be seen in nephritis, liver dysfunction and hypogammaglobulinemia.
A/G (albumin/globulin) Ratio: The liver can function adequately on 20% of liver tissue, thus early diagnosis by lab methods is difficult. A reversed A/G ratio may be a helpful indicator. The A/G ratio may be elevated in hypothyroidism and high protein/high carbohydrate diet with poor nitrogen retention. The A/G ratio may be decreased in liver dysfunction.
Total Bilirubin: Total bilirubin is the pigment in the blood that makes the plasma or serum part of your blood, yellow. When bilirubin level in the blood is very high for a period of time, the whites of your eyes and your skin may become yellow – this is known as jaundice. Bilirubin comes from the breakdown of old red cells in the blood by the liver. A high bilirubin level in the blood can be caused by red blood cells being destroyed, by the liver, or by a blockage of bile ducts.
Alkaline Phosphates (ALP): Alkaline phosphates is an enzyme that is found in many body tissues, but the most important sites are bone, liver, bile ducts and gut. A high level of alkaline phosphates in your blood may indicate bone, liver, or bile duct disease. Certain drugs may also cause increased levels. Growing children, because of bone growth, normally have higher levels than adults. Low values are not generally considered significant.
Gamma-Glutamyltransferase (Gamma GT): Gamma GT is enzyme that is primarily found in the liver. Drinking too much alcohol, certain drugs, liver disease, stress, physical exertion, some common medications and bile duct disease can cause high levels of Gamma GT in the blood.
Aspartate aminotransferase (AST): AST is found in high concentration in heart muscle, liver and skeletal muscle. It is released into the blood stream when any of theses organs are damaged. Increased levels are usually associated with liver disease or heart attacks.
Alanine aminotransferase (ALT): The ALT enzyme is found mainly in the liver. ALT values are usually compared to the levels of other enzymes, such as alkaline phosphates and AST, to help determine if liver disease is present. Very high levels of ALT (more than 10 times the highest normal level) are usually due to acute hepatitis, often due to a virus infection.
Lactate dehydrogenase (LDH): LDH is most often measured to check tissue damage. The enzyme LDH is in many body tissues, especially the heart, liver, kidney, skeletal muscle, brain, blood cells and lungs. Higher than normal levels may indicate cerebrovascular accident (stroke), heart attack, low blood pressure, infectious mononucleosis, blood deficiency, muscle injury and tissue death.
Glucose: A blood glucose test measures the amount of a type of sugar, glucose, in your blood. Glucose comes from carbohydrate foods. It is the main source of energy used by the body. Insulin is a hormone that helps your body use and control the amount of glucose in your blood. Insulin is produced in the pancreas and released into the blood when the amount of glucose in the blood rises. Blood glucose levels that remain high over time can damage your eyes, kidneys, nerves and blood vessels.
Uric Acid: Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in some foods and drink, such as liver, anchovies, mackerel, dried beans and peas, beer and wine. Most uric acid dissolves in blood and travels to the kidneys, where it passes out the urine. High blood levels may cause gout arthritis or kidney stones. Kidney disease, stress, alcohol, and certain diuretics may raise the level.
Calcium: Calcium, the most abundant mineral in the human body, has several important functions. More than 99% of total body calcium is stored in the bones and teeth where it functions to support their structure. The remaining 1% is found throughout the body in blood, muscle, and the fluid between cells. Calcium is needed for muscle contraction, blood vessel; contraction and expansion, the secretion of hormones and enzymes, and sending messages through the nervous system. The parathyroid gland is the main regulator of calcium in the body. Low levels of calcium in the blood are associated with malnutrition. High levels can be caused by bone disease, excessive use of antacids and milk, overdosing on vitamin D and hyperparathyroidism.
Phosphorus: Phosphorus is a mineral that is present in every cell of the body, but 85% of the body’s phosphorus is found in the bones and teeth, which is its main function. It plays an important role in the body’s utilization of carbohydrates and fats and in the synthesis of protein for the growth, maintenance, and repair of cells and tissues. It is also crucial for the production of ATP, a molecule the body uses to store energy. There is generally no deficiency in phosphorus because it is so readily available in the food supply. High levels in the blood usually occur in people with severe kidney disease and severe dysfunction of their calcium regulation.
Magnesium: Magnesium is an essential mineral for human nutrition and in the body serves several important metabolic functions. It plays a role in the production and transport of energy. It is important for the contraction and relaxation of muscles. Magnesium is involved in the synthesis of protein, and it assists in the functioning of certain enzymes in the body. A low level of magnesium in the blood may indicate severe malnutrition, severe diarrhea, alcoholism or excessive use of diuretics. A very low level can cause your muscles to tremble. High levels may indicate kidney disorder.
Platelets are the smallest type of cell found in the blood. Platelets help stop bleeding after an injury by gathering around the injury site, plugging the hole in the bleeding vessel and helping the blood to clot more quickly. If a patient does not have enough platelets, he will be at an increased risk of excessive bleeding and bruising. Some people will have statistically abnormal platelet counts while having no abnormality, although the likelihood increases if the platelet count is either very low or very high. High counts or thrombocytosis may lead to thrombosis (clotting).
MPV (mean platelet volume) reflects the average volume of platelets and varies with platelets production. The average platelet size is larger when the body is producing increased number of platelets. MPV test results can be used to make inferences about platelet production in the bone marrow.
Patients who have a keen interest in their own healthcare frequently want to know what they can do to change their WBCs, RBCs and platelets. Unlike “good” and “bad” cholesterol, cell populations are not generally affected by lifestyle changes unless the patient has an underlying deficiency (such as vitamin B12 or folate deficiency). There is no way that a patient can directly raise the number of his/ her WBCs or change the size or shape of his/her RBCs. Addressing any underlying disease or conditions and following a healthy lifestyle will help optimize your body’s cell production and your body will take care of the rest.
Red Blood cells are the most common type of cell in the blood. They are reddish in color and shaped like a donut with a thinner section in the middle instead of a hole. RBCs are produced by the bone marrow continuously in health adults. The cells contain hemoglobin, which carries oxygen and carbon dioxide throughout the body. The CBC determines whether there are sufficient RBCs present and whether the population of cells appears to be normal. Low red blood cells are commonly caused by iron deficiency anemia, due to chronic blood loss, acute blood loss, and hereditary disorders (sickle cell anemia). Anemia symptoms may be fatigue and weakness.
Much less frequent, there may be too many RBCs in the blood (polycythemia). In extreme cases, this can interfere with the flow of blood through the veins and arteries.
Thyroid stimulating Hormone (TSH): TSH is the pituitary hormone which helps regulate thyroid gland activity. TSH stimulates the thyroid to produce thyroid hormone. When the thyroid gland fails, due to primary disease pf the thyroid, pituitary TSH increases. This is called primary hypothyroidism. In contract, when the thyroid gland is overactive and producing too much thyroid hormone, the serum TSH decreases. This condition is called primary hyperthyroidism. Both primary hypothyroidism and hyperthyroidism can be detected by the sensitive TSH method. In addition, the TSH test can monitor your dose of thyroid medication.
Hemoglobin A1C: Hemoglobin A1C test reflects your glucose (blood sugar) control over the past 3 months. Testing your A1C level every 3 months is the best way for you and your doctor to understand how well your glucose levels are controlled.
Prostatic Specific Antigen (PSA): (screening for males) PSA is a blood test that measures a protein that is lonely produced by the male prostate gland. Elevations of PSA may occur in men with prostate cancer or non-cancerous prostatic diseases. A normal PSA level does not entirely exclude the possibility of prostate cancer. Although high PSA values do not always indicate prostate cancer, all elevated values should be reported to your health care provider for further evaluation.
There are five different types of white blood cells that the body uses to fight infections or other causes of injury. These types - neutrophils, lymphocytes, basophils, eosinophils and monocytes - are present in relatively stable percentages that may be temporarily shifts higher or lower depending on what is going on in the body.
Neutrophils (Neut): Neutrophils are the most abundant of the circulation white cells; they are also the shortest lived in the circulation. Being highly motile, neutrophils quickly congregate at a focus of infection. A high count is seen in infections, some cancers, arthritis and sometimes when the body is under stress (after surgery, trauma, or heart attack). Low counts can be congenital or it can be the result of aplastic anemia, some kinds of leukemia or the side effect of medication (chemotherapy).
Lymphocytes (Lymph): A small white blood cell that plays a large role in the defending the body against disease. Lymphocytes are responsible for immune responses, and their functions are diverse and complex. A low count maybe seen in AIDS, while high counts can be seen in viral infection such as the flu.
Monocytes (Mono): Monocytes are part of the human body’s immune system that protects against blood-borne pathogens and moves quickly to sites of infection in the tissues. Monocytes which migrate into other tissues develop into macrophages. Elevated counts can be seen in chronic infections.
Eosinophils (Eos): Eosinophils are white blood cells of the immune system that are responsible for combating infection of parasites and they control the mechanism associated with allergy and asthma. Increased eosinophil count often indicates allergies, skin disease or parasitic infections.
Basophils (Baso): Basophils are the least common of the white blood cells. Their function is not fully understood, but they are capable of ingesting foreign bodies and are associated with asthma and allergies.
Large unstained cells (Luc): Large unstained cells, a small portion of the total white blood cells as function of the instrument performing the CBC, are large cells which do not stain. The Medical Technologist of the testing laboratory evaluates these results to insure that atypical cells are not present when the count is elevated.
White blood cells are your body’s protectors. White blood cells are larger than red blood cells, but there are fewer of them. Both increases and decreases can be significant.
When you have an infection, increased numbers of WBCs are sent from the bone marrow to attack the bacteria or virus that is causing the infection. An increased number of WBCs may occur with mild infections, appendicitis, pregnancy, leukemia, hemorrhage, and hemolysis. Strenuous exercise, emotional distress and anxiety can also cause an increase.
A low WBC count makes it harder for your body to fight off an infection. People with a low WBC are likely to catch colds or other infectious diseases. Low WBC count may be seen in: overwhelming infections, lupus, cirrhosis of the liver, certain types of drug therapy and cancer.