This is an up-to-date version of an explanation we handed out with blood panel results when we had a blood draw station at the clinic.
This list is for information only. Only your provider is authorized to make judgments about your health or treatment based upon lab work.
Also, when reviewing lab work, understand that ranges of normal vary between laboratories depending on different methods of testing. Aside from that, numbers outside the range may or may not signal illness. For example, the normal range of height for American men is 5’ 4” to 6’ 2”. If you measure somewhat taller or shorter, most often that's not due to illness.
Complete Metabolic Panel - CMP
Section titled “Complete Metabolic Panel - CMP”Glucose Fasting blood sugar runs normally between 65 and 100, up to 180 in the first hour after a meal, and less than 140 after two hours. Generally blood sugar must run above 300 to 400 for a matter of days or weeks to cause symptoms.
We consider a person to have type II diabetes if their fasting blood sugar is over 125 on two separate occasions.
The best test for hypoglycemia is to measure blood glucose when you are having symptoms.
BUN and creatinine are waste products carried by the blood. Their level is a balance between their rate of production and their rate of elimination through the kidney. If the creatinine is high this is almost always due to kidney problems. The BUN can rise simply because of excessive protein and inadequate fluid intake. BUN/creatinine ratio can be abnormal in various heart, kidney and other disorders. Most commonly an abnormal BUN/creatinine ratio is of no significance.
Estimated glomerular filtration rate (Glom filt rate, est or eGFR) Using age, gender, race, and creatinine, an estimate is made of how much blood the kidneys process in a minute (the GFR). The formula is significantly wrong 30% of the time, and is most useful in people with moderate (or worse) chronic kidney disease. GFR naturally declines as we age, and we see many healthy people over 60 with an eGFR between 50 and 60.
Sodium [as in sodium chloride (table salt)]. It is the major mineral in the fluid between the cells of the body, including the serum (the watery portion of the blood). It can be high or low in several dozen different illnesses. Most commonly it is abnormal with diarrhea, vomiting or dehydration. Excessive use of diuretic drugs can raise the sodium level.
Potassium is the active ingredient in most salt substitutes. It tastes more bitter than table salt.
Potassium is predominant inside the cells of the body. The most common reason for a high potassium is that the red blood cells in the specimen collection tube have leaked some of their potassium out into the blood serum. (Most lab measurements are made on the serum or the liquid portion of the blood after the red blood cells have been removed).
True alterations of potassium level in the blood can have very adverse effects on the heart including cardiac arrest. There are many causes for abnormal potassium levels. The most common reason for the potassium to be low is diuretic drugs (fluid pills). Potassium can be high from diuretic drugs containing spironolactone or from the blood pressure drugs of the ACE inhibitors class.
Chloride is the other half of table salt, sodium chloride. Most of the illnesses that change sodium or potassium can have an effect on chloride as well. A 1 or 2 point elevation in chloride is rather common in healthy people.
Total protein By convention this is the total of the albumin and the globulin of the blood.
Albumin is the major protein in the blood. It thickens the blood so that the blood stays in the blood vessels. It is a storage form of protein. It helps carry fatty acids and bile through the blood as well as other hormones, amino acids, drugs and so forth. High levels are generally of no consequence. Low levels can occur with kidney disease, malnutrition, or other illnesses.
Globulin These are the proteins in the blood that have to do with immunity. The gamma subfraction of the globulins, the gamma globulins, are often given as an injection to prevent hepatitis. There are many subfractions of globulin.
Albumin/globulin ratio This can be altered by factors which influence the albumin or globulin above.
Calcium Levels of calcium in the blood are difficult to measure, so a high or low reading is often due to laboratory difficulty. Usually when a generally healthy individual has an abnormal value we will simply repeat the test. Changes in the amount of protein in the blood can affect calcium levels. Calcium levels can be high with excessive vitamin D intake or with thiazide diuretics. Various hormonal diseases can raise or lower the calcium level. Calcium abnormalities can cause cardiac or other muscular irritability.
Phosphorus combined with calcium produces the very hard mineral of the bone. Phosphorus is very important in producing the energy containing compounds in the body that we call ATP. Phosphorus levels can vary with calcium, vitamin D intake, bone diseases or various hormonal and chemical imbalances. Numerous drugs can affect the phosphorus level.
Liver enzymes The next six tests are the liver panel. In people with hepatitis many of these will be elevated to levels of several hundred or a thousand.
SGOT This enzyme has several other names, including glutamate-oxaloacetate transaminase, aspartate aminotransferase and AST.
It is present in most organs of the body. Most commonly we see it elevated in people with liver disease. It can also rise due to other illness, and to various drugs including various antibiotics. It can be low in diabetic ketoacidosis, in B6 deficiency and in vitamin B1 (thiamine) deficiency.
SGPT (serum glutamic-pyruvic transaminase, or ALT, for you biochemists). The most common reason for elevation of this enzyme is liver disturbance.
Alk phos Alkaline phosphatase. This is generally included in the list of liver enzymes as it is frequently elevated with liver disturbances. However it is high in all children as well as in the elderly due to normal processes in the skeleton.
Alkaline phosphatase can be low with vitamin C deficiency and excessive vitamin D. Certain drugs can affect the level of alkaline phosphatase.
LDH Lactic dehydrogenase has sub-fractions and can rise with damage to various tissues in the body. Elevations are sometimes important, sometimes not.
Total bilirubin We recycle our red blood cells every 4 months. The hemoglobin in the red blood cell is transformed into a yellowish green pigment called bilirubin. This is eliminated through the bile giving the bile its green color and giving the stool its mahogany color. When the flow of bile from the liver is blocked, the stool usually will become a beige or tan color. The bilirubin then builds up in the blood.
Mild elevations up to 1.5 or 1.8 are frequently due to an inherited condition called Gilbert's Syndrome. People with this syndrome live just as long as anyone else, suffer no difficulty whatsoever, and simply have a slightly higher-than-average bilirubin because the enzyme systems that move bilirubin out of the liver simply move it a little more slowly. Bilirubin can be high in the newborn with levels up to 10 or 15 without much difficulty, although if levels go higher than this the infants are treated to prevent brain damage. High bilirubin levels in an adult never cause brain damage. Hepatitis causes an increase in the level of bilirubin, which causes the yellowish tint to the skin and white portion of the eye.
GGT gamma-glutamyl transferase: This liver enzyme is sensitive to alcohol use. Normals listed by most laboratories range to the 70 to 85 range because so many people use alcohol. When a person doesn't use alcohol, GGT is rarely above 20. Most people have to consume a fair amount of alcohol to get the GGT up above 50.
Uric acid Uric acid is a waste product. It does have a beneficial effect in that it is a free radical scavenger. High uric acid levels are very common in normal healthy people and often related to high protein intake and alcohol use. Uric acid levels can run high with gout, weight gain, and in certain ethnic groups such as Filipinos.
Lipid Panel
Section titled “Lipid Panel”Cholesterol Our liver makes about 1,000 mg of cholesterol a day which is equivalent to the amount of cholesterol in about 4 eggs. Cholesterol can dissolve in fat or in oil but is not a fat. The body transforms cholesterol into estrogen, testosterone, cortisone, vitamin D and many other important substances. The membranes of the cells in our brain require cholesterol. Low levels of cholesterol can result in depression and an increased tendency to develop cancer. However, most folks with high or low cholesterol do not develop any trouble. If you go to an intensive care unit and look at the people with heart attacks, only about four out of ten will have a high cholesterol.
The theory used to be that cholesterol "gummed up the arteries" resulting in blockage and therefore a heart attack. We now know that there is a lot more to it than that. On the laboratory sheet the listing under "cholesterol" is actually the total cholesterol, made up of these three subcategories.
The first subcategory is HDL cholesterol (High Density Lipoprotein cholesterol). This fraction of cholesterol is very dense, something like a sponge to soak up the other kinds of cholesterol. In general the higher the HDL, the less likely you are to have heart disease. People with a level above 80 or 90 are extremely unlikely to develop heart disease.
The second kind is the LDL, the Low Density Lipoprotein cholesterol. This is an active fraction of cholesterol. It is extremely important in carrying out the beneficial functions of cholesterol. It is, however, susceptible to free radical damage. LDL cholesterol is susceptible to oxidation by free radicals resulting in the formation of lipid peroxides, which can increase arteriosclerosis. The LDL cholesterol, then, is something like the hay in a farmer's barn. He needs the hay but if someone is throwing matches around (free radicals) then he is at a little bit higher risk to have his barn catch fire.
The final kind of cholesterol is the VLDL or Very Low Density Lipoprotein cholesterol. This is usually not listed on a laboratory report form but an estimate of it can be gotten by subtracting the LDL and the HDL from the total cholesterol. This, like LDL, is an active cholesterol.
Risk ratio In general, the greater the total cholesterol compared to the HDL cholesterol, the higher a person's cardiac risk is. This is expressed as the risk ratio (the total cholesterol divided by the HDL cholesterol). This ratio can be altered with exercise, diet and nutritional factors.
Cholesterol is one of the least important risk factors for heart disease. More important risk factors include stress, satisfaction with one's job or life, smoking, diabetes, weight, and hypertension. There are many people with elevated cholesterol who live long, happy and healthy lives. However, if you have a high cholesterol level, you should discuss it with your physician.
Triglycerides Triglycerides are the true fats in the blood. If you eat a chocolate eclair the fat in the creamy filling is carried from your intestine to your liver and to your fat deposits in the form of triglycerides. Just as a detergent will carry the fat off the plate and down the drain without sticking to anything else, the triglycerides help the fat move around the body without it sticking to the blood vessels. Moderate elevation of triglyceride is usually due to a recent meal or to a diet that is too rich in fat. Triglyceride is considered to be a much lower risk factor for cardiac disease than cholesterol.
Complete Blood Count - CBC
Section titled “Complete Blood Count - CBC”WBC WBC stands for white blood cell count. When this is high, it is generally due to infection; much less commonly this could be due to leukemia. Low white count can sometimes be due to illness. However, statistics show that people whose white count runs around the lower range of normal tend to live longer. White counts can change in a matter of hours with infection. High normal white counts indicate systemic inflammation and increased risk of heart disease.
There are different kinds of white blood cell…
Neut Neutrophils are frequently elevated in people with bacterial infections. These are also called Polys or PMNs for polymorphonuclear leukocytes.
Lymph Lymphocytes may rise with a viral infection. A sub-fraction of lymphocytes is affected by the AIDS virus.
Mono Increased monocytes indicate excessive inflammation.
Eosin Eosinophils can be elevated with allergy. However, most people with allergy do not have high eosinophil levels.
Baso Basophils can increase with numerous illnesses, including leukemia and other blood disorders.
These types of WBC are reported as a percentage of the total or as the absolute (actual) number in a microliter (uL) of blood.
Tests for anemia Uncommonly, people can have too many red blood cells. More common is anemia, too few red blood cells. The most common cause of anemia is loss of iron. A person can lose a good deal of iron before they become anemic. These tests for anemia are most interesting when we are determining what kind of anemia a person has.
RBC This is the number of millions of red blood cells per cubic millimeter of blood.
Hgb Hemoglobin in the red blood cell gives blood its red color and carries oxygen.
Hct Hematocrit. If you spin blood in a tube, the hematocrit is the percentage of red blood cells at the bottom of the tube. Above the red blood cells in the tube is the serum or plasma.
MCV Mean corpuscular volume. The average volume of a red blood cell.
MCH Mean corpuscular hemoglobin. The average amount of hemoglobin in each individual red blood cell.
MCHC Mean corpuscular hemoglobin concentration. The concentration of hemoglobin in each RBC.
Platelets These are small objects in the blood perhaps a 10th of a diameter of a RBC, and they are involved in the clotting process. Platelet counts can be high with arthritis, liver disease, malignancy and many other disorders, although most frequently when they are high a person does not have any serious illness. There are many illnesses that can cause the platelet count to be low. Platelet counts can be as low as 40 or 50 thousand without major bleeding.
RDW Red cell distribution width. The average red blood cell is about 8 microns in diameter, but just as in people there is some natural variation. RDW measures this degree of variation, which is high with B 12 deficiency, during treatment for iron deficiency and with various other disorders.
Special Tests
Section titled “Special Tests”Ferritin This protein in the blood is involved with iron metabolism. Although we can measure iron directly in the blood, the ferritin level is a much more sensitive indicator of the amount of iron available for the body's use. Iron is important to the immune system and to the energy systems as well as in the manufacture of hemoglobin. Up to 1/3 of women are deficient in iron.
The normal values on the lab report form are incorrect. Low normal for women is 22, though some women will not grow hair normally with a ferritin level under 50.
TSH Thyroid stimulating hormone is made by the pituitary gland in the brain. This gland senses the amount of thyroid in the blood stream and the body's requirements for thyroid hormone. When the pituitary senses that we need more thyroid hormone it will put out higher levels of TSH. This travels in the blood to the thyroid gland in the neck, and tells it to make more thyroid hormone. Therefore, if the thyroid is making less thyroid hormone than we need, TSH levels will rise. On the other hand, if a person is making or taking too much thyroid hormone, TSH levels will fall below normal. There are some people with thyroid disease who have a normal TSH. It takes about 8-12 weeks for TSH levels to reach a stable value once the dose of thyroid medication has been changed.
Methylmalonic acid is a substance that appears in the urine in greater amounts in people with B12 deficiency. Sometimes we use this as a test of B12 deficiency.
Neutrophil Segmentation -(also called Lobe Count Neutrophils) The nucleus of certain white blood cells called neutrophils can take different shapes depending on the amount of folic acid in your blood. Too little folic acid and the nucleus of the cell becomes "hypersegmented." The laboratory computer is set to allow up to 17% of neutrophils to be hypersegmented, and to consider that normal. I am one of those that believes that no neutrophils should be hypersegmented. In other words, there should be 0% of hypersegmented neutrophils. If there are any hypersegmented neutrophils, enough folic acid should be taken to push the ratio of hypersegmented to normal neutrophils down to 0.
Sedimentation Rate Anticoagulated blood is left to sit in a tube. The red cells will settle to the bottom of the tube, leaving clear plasma at the top. The laboratory can measure how quickly these red cells move to the bottom of the tube. This is called the sedimentation rate, and is expressed in number of millimeters distance the line separating the red cells and the plasma moves down the tube in an hour. If the red cells fall quickly to the bottom of the tube, this is usually due to inflammatory proteins in the blood. The test therefore measures inflammation. It can be high with thyroid disease, heart attack, infection, pregnancy, cancer, poisoning, and inflammatory arthritis. Current measurements are automated and differ from the original method described above.
C-reactive protein (CRP) Elevated CRP indicates inflammation, either from infection, arthritis or other causes. Increased inflammation is associated with heart disease, and can be treated if present. Knowing your CRP allows a much more precise estimate of your degree of risk of stroke and heart attack.