Download Lab Test Explanations

Lab Test Explanation Sheet—BFM Highland Village
Lipid Panel
Cholesterol
A molecule which serves important functions, but if too high can lead to clogging of the arteries, i.e., cardiovascular disease
or CVD, which consists mainly of heart or coronary artery disease (CAD) and stroke. There are many types—HDL and
LDL are the most important (see below), but there are also subtypes that are getting more attention these days.
Triglycerides
These make up the other major fatty molecules in the blood (besides cholesterol), and can also be associated with CVD.
These increase especially after a fatty meal, which is why it is important to be fasting for a more accurate reading.
HDL
“High density lipoprotein,” which is considered the “good” or protective cholesterol. It is a molecule that contains a high
proportion of protein to cholesterol. High levels are associated with a decreased risk of CVD, so the higher it is, the better.
It is often difficult to increase (genetics play a big role), but exercise, weight loss, smoking cessation, and eating “good”
types of fat (olive and canola oil, flaxseed, fish, natural nuts and avocados, in moderation) can help.
LDL
“Low density lipoprotein,” considered the “bad” cholesterol. It has a low proportion of protein to cholesterol, and high
levels are associated with an increased risk of CVD. Red meat, dairy products, saturated fats (like shortening), a sedentary
lifestyle, and weight gain can make this go up. Usually, the lower this is, the better, and those with other risk factors for
CVD should try to achieve an LDL <100 or even <70 if there are major risk factors like diabetes and previous heart disease.
Risk Ratio
This is a ratio of the LDL to the HDL cholesterol (LDL/HDL). Many believe this is a more important predictor of actual
risk for developing heart disease, but an elevated LDL should probably still be treated even if the Risk Ratio is normal.
General Health Panel (includes “Comprehensive Metabolic Profile” or “Chem 17”, CBC and TSH)
Glucose
This is the sugar in the blood. High fasting values are associated with diabetes. Low values are usually not concerning
unless they are very low (<50 or so) and associated with symptoms of hypoglycemia (e.g., cold sweats, dizziness,
weakness).
BUN
“Blood urea nitrogen,” a waste product produced by the liver and excreted by the kidneys. High values may mean the
kidneys aren’t working too well, but can also occur because of a high-protein diet or strenuous exercise. Low values are
usually insignificant unless malnutrition is a concern.
Creatinine
This is also a waste product excreted by the kidneys, but it is not affected by diet. If high, it means that kidney function is
decreased, and requires further evaluation. Low values are usually insignificant.
BUN/Creat.
This is a ratio of the BUN to the creatinine, and usually is irrelevant if the BUN and creatinine are normal. Otherwise, high
values can signal dehydration.
Sodium
A major salt component—levels are regulated by the kidneys and adrenal glands. It is important in the functioning of nerve,
muscle and other cells. High or low values, if persistent or excessive, should be evaluated.
Potassium
An electrolyte important in nerve and muscle impulses, especially in the heart. Levels are regulated by the kidneys. High or
low values, if persistent or excessive, must be evaluated.
Chloride
A molecule usually attached to sodium or potassium to create a salt—it is regulated mostly by the kidneys. High or low
values need to be evaluated if excessive.
Carbon Dioxide
A byproduct (“CO2”) of oxygen metabolism that reflects lung and kidney function. Changes are frequent and are not
concerning unless excessive or persistent.
Calcium
A molecule important in bone formation, but also in blood clotting and nerve, muscle and other cell activity. Levels are
controlled by the parathyroid gland and the kidneys, so abnormal levels may signal their malfunction.
Protein
An important component of blood, contributing to immune function, drug and hormone binding, and a variety of other
processes. The total protein level is a sum of the albumin and globulin levels.
Albumin
The major protein in the blood. It provides an important index of nutrition.
Globulin
The rest of the proteins in the blood (besides albumin), consisting of the antibodies that are important in fighting disease.
Low levels may signal immune deficiency. If only mildly elevated, it is usually insignificant, but very high levels require
further evaluation.
A/G ratio
“Albumin/globulin ratio”—abnormal values are usually insignificant if the albumin and globulin values are normal.
Bilirubin
A molecule produced mainly by the liver from hemoglobin metabolism. It is a major component of bile, which is stored in
the gallbladder. Low values are usually insignificant, but high values may signal liver or gallbladder disease. When it is
found elevated, it is important to test the levels of the two different types of bilirubin—“direct” (conjugated) and “indirect”
(unconjugated) bilirubin. If the total bilirubin is high only because the indirect bilirubin is high, it is usually of no concern.
Alkaline Phosph. This is an enzyme found in the liver, bone, placenta, intestine, and other tissues. High levels are normal in growing children
and pregnant women, but may otherwise signal bone, liver or intestinal disease. Low values are probably not significant.
SGOT (AST)
“Serum glutamic-oxaloacetic transaminase” (“aspartate aminotransferase”)—a major liver enzyme, but also found in the
heart, muscles and other tissues. Low values are usually not significant, but high values suggest liver or other disease, and
should be evaluated. AST levels that are significantly more elevated than ALT levels suggest alcoholic liver disease or heart
disease.
SGPT (ALT)
“Serum glutamic-pyruvic transaminase” (“alanine aminotransferase”)—the most important liver enzyme, but can also be
found in other tissues. Low values are usually not significant, but high values usually suggest liver disease and should be
evaluated.
CBC (Complete Blood Count)
WBC
“White blood cells/count”—WBCs are important for fighting infections. Elevated levels suggest an infection or
inflammatory state, but can also occur with steroid or other medication use or when one is stressed (physically or
emotionally). Extremely high counts occur in leukemia. Low levels may suggest a viral infection or other blood disorder.
RBC
“Red blood cells/count”—RBCs carry hemoglobin, which transports oxygen to the body’s cells/tissues. Elevated levels are
concerning only if excessive, but low levels can accompany anemia.
Hemoglobin The iron-containing pigment molecule in the RBCs, which carries oxygen. Elevated levels are concerning only if excessive,
but low levels mean you are anemic, and should be investigated and treated if possible.
Hematocrit
The percentage of blood volume taken up by RBCs. It usually goes up and down together with the hemoglobin. Levels can
rise in high altitudes and smokers.
MCV
“Mean corpuscular (RBC) volume”—the average size of the RBC. Low levels can occur in iron deficiency and other
anemias, and high levels can occur in “pernicious anemia” and alcohol abuse.
MCH
“Mean corpuscular (RBC) hemoglobin”—the average amount of hemoglobin in the RBCs. Isolated abnormal values are
usually insignificant.
MCHC
“Mean corpuscular (RBC) hemoglobin concentration”—the MCH expressed as a percentage. Isolated abnormal values are
usually insignificant.
RDW
“RBC distribution width”—a measure of how variable the sizes of the RBCs are. Elevated values can occur in different
types of anemia.
Neutrophils The most common type of WBC, important in fighting infections, especially bacterial. Abnormal levels in the absence of an
abnormal WBC are usually not significant, but can suggest a bacterial infection or blood disorder if both are low.
Lymphocytes The second most common type of WBC, important in fighting infections, especially viral. Abnormal levels in the absence
of an abnormal WBC are usually not significant, but can occur in viral infections, immune deficiency, and blood disorders.
Monocytes
A less common type of WBC—elevations are usually not significant, but can occur in some infections, medication use, and
blood disorders.
Eosinophils
A less common type of WBC—elevations are usually not significant, but can occur in allergic states, parasite or tuberculosis
infections, and some blood disorders.
Basophils
A less common type of WBC—elevations are usually not significant, but can occur in allergic states and some blood
disorders.
Platelets
Important in clotting of the blood—a high value is usually not worrisome (unless very high), and low values can lead to
delayed coagulation and excessive bleeding (especially if below 10-25,000).
TSH
“Thyroid stimulating hormone”—the hormone produced by a gland below the brain called the pituitary gland, which in turn
stimulates the thyroid (a gland in the neck that regulates metabolism) to produce thyroid hormone. Its secretion is controlled
by a feedback mechanism depending on your levels of circulating thyroid hormone. Levels go up when your thyroid isn’t
producing enough hormones (“hypothyroidism”), and down when it’s producing too much (“hyperthyroidism”).
Urinalysis
Color/Appear.
Specific grav.
Leukocyte est.
Nitrite
pH
Protein
Glucose
Ketones
Urobilinogen
Bilirubin
Occult blood
Normal is yellow or straw color. It is yellow mainly because of excretion of a pigment called urochrome, which increases
with metabolic rate. The more water you drink, the more dilute (and therefore the less yellow) your urine will be. Cloudy
urine can be from crystals, white cells or bacteria. Other colors need evaluation.
Reflects how concentrated the urine is. Low concentration can signal kidney or adrenal disease, and high concentration can
signal dehydration, congestive heart failure, and adrenal or liver disease.
A protein or enzyme found in white blood cells (WBCs), thus serving as a marker for the presence of WBCs. If present in
significant numbers, it suggests a urinary tract infection.
A chemical created (from nitrate) by many types of bacteria that can infect the urinary tract. Its presence suggests infection.
Indicates how acidic the urine is, which is usually a reflection of the acidity of the blood (“acidosis”). The pH number is
inversely related to the acidity (the lower the pH, the more acidic). The pH level decreases in diets high in meat protein and
some fruits such as cranberries, and increases in diets high in certain fruits and vegetables, especially citrus fruits.
Abnormal if found in significant amounts in the urine. Its presence can signal kidney disease, and needs to be evaluated.
Abnormal if found in the urine, and usually signals diabetes; however, it can be elevated in other endocrine diseases such as
Cushing’s syndrome, hyperthyroidism, pheochromocytoma, and others.
A byproduct of fatty acid metabolism, which shows up in the urine when levels are increased in the bloodstream, occurring
when there is a deficiency of carbohydrates that the body can use as fuel (e.g., as in acute febrile illness, malnutrition, lowcarbohydrate diets & dehydration). In diabetics, their presence can signal severe illness.
A byproduct of bile metabolism, usually processed by the liver. Its presence in the urine can suggest decreased liver
function, congestive heart failure or biliary infection with obstruction.
A breakdown product of hemoglobin, formed in the liver, spleen and bone marrow. Excess of a certain type (“direct
bilirubin”) in the bloodstream may show up in the urine, signaling liver disease or bile outflow obstruction.
May be insignificant, but must be worked up if persistent, as it may signal urinary tract infection, kidney stones or other
disease, tumor, or bleeding disorder.
Updated 9-28-04