|
|
What Do My Lab Tests Mean? |
|
WHAT DO MY LAB TESTS MEAN?
The tests we discuss below have hypertext links to a website that can give you more information than the brief information here; the site also discusses tests not reviewed below, and symptoms that can be associated with the abnormalities. Another source of information about lab tests is at http://www.nlm.nih.gov/medlineplus/laboratorytests.html.
Liver Tests: (ALT, AST, ALK Phosphatase, Bilirubin)
http://www.labtestsonline.org/understanding/analytes/liver_panel/glance.html
Alkaline Phosphatase is an enzyme (protein) found in the liver, bone, and intestinal tissues. In the liver, it is mainly located in the ducts (tubes) that run throughout the liver. Some causes of elevated levels include:
Drug reaction (medication side effect)
Anticonvulsant use (phenytoin/Dilantin, Phenobarbital)
Alcoholism
Diabetes mellitus
Liver Disease (especially obstruction of the ducts), including hepatitis, cirrhosis
Gallstones
Bone Disease, including Pagets Disease
Bone Cancers, pancreas cancer, some blood cancers (multiple myeloma), other cancers
Hyperthyroidism, Hyperparathyroidism
Lymphoma
Leukemia
Cancer metastases to the bone
Kidney disease, severe
Infection of the bone (osteomyelitis)
Pregnancy
Fractures, extensive, associated with healing
Infections involving the liver (tuberculosis, abscess)
Mono
Some causes of decreased levels include:
Anemia from B-12 deficiency
Celiac Disease
Hypothyroidism
Malnutrition
Zinc or Magnesium Deficiency
Vitamin D Intoxication
ALT (Alanine Transaminase) is an enzyme found in the liver, pancreas, and skeletal muscle. It acts as a catalyst in the process necessary for amino acid production; the body uses amino acids to make proteins. Some causes of elevated levels include:
Drug (medication) effect
Obesity
Liver Disease (obstruction and infection)
Fatty liver (steatosis)
Liver Cancer
Congestive Heart Failure
Reyes Syndrome
Mononucleosis
Muscular Dystrophy
Some causes of decreased levels include:
Cancer
AST (Aspartate Transaminase) is a catalytic enzyme found in the liver, skeletal muscle, and cardiac tissue. Often both the AST and ALT will be elevated for the same reason. Some causes of elevated levels include:
Drug (medication) effect
Alcoholic hepatitis
Liver Disease (including infection, especially hepatitis; cirrhosis)
Blockage of the bile drainage, including gall stones in the bile duct
Liver Cancer
Congestive Heart Failure
Myocardial infarction (heart attack)
Pancreatitis
Stroke
Reyes Syndrome
Mononucleosis
Some Causes of decreased levels include:
Dialysis
Bilirubin (Total) is produced in the liver, spleen, and bone marrow. It is a by-product of hemoglobin breakdown. Bilirubin is found in direct (conjugated) and indirect (unconjugated) fractions. Some causes of elevated levels include:
Hepatitis (viral, alcohol-related, toxin-related, drug-related)
False elevation due to drugs/chemicals in the blood
Inherited (genetic) disorders, such as Dubin-Johnson syndrome, Gilberts disease
Obstruction of the bile system
Cancer
Infection (abscess)
Anemia, including B12 deficiency and sickle cell anemia
Alcoholism
Destruction of red blood cells (inherited, severe infections, immune diseases)
Mononucleosis
Pulmonary Embolism
Transfusion Reactions
Malaria
Toxic Shock Syndrome
Certain Medications
Some causes of decreased levels include:
Certain Medications (but not considered to be clinically significant)
Lipids
Cholesterol is a fat. It is found in all body tissues and plays a vital role in cell membranes. Over 90% of the cholesterol in our blood is made in our liver. This cholesterol is made primarily from saturated fats. One type of cholesterol subfraction (LDL) is associated with damage to the inner lining of the blood vessels. Optimally, the total cholesterol should be under 200. More important than the total cholesterol are the subfrations, noted below. Note that low cholesterol is unknown to cause any disease, although it can be seen in some diseases.
Some causes of increased levels include:
Genetics (most common cause)
Celiac disease
Pancreatitis
Hypothyroidism
Liver/gallbladder disease
Kidney failure
Certain medications, including beta blockers, contraceptives, anabolic steroids
Some causes of decreased levels include:
Acute illness
Malnutrition
Liver disease
Certain cancers
Certain medications, especially those used to treat cholesterol
http://www.labtestsonline.org/understanding/analytes/cholesterol/glance.html
HDL Cholesterol is a protective subfraction of cholesterol. The higher the level, the better.
http://www.labtestsonline.org/understanding/analytes/hdl/glance.html
LDL Cholesterol is a sub fraction of cholesterol associated with heart disease and stroke. There are different cutoffs for normal, depending on risk factors for heart disease (like diabetes, high blood pressure, smoking, and more.)
http://www.labtestsonline.org/understanding/analytes/ldl/test.html
Triglycerides (TG) are a long chained fatty acid. TG are absorbed through the intestines and stored in fat cells. TG are also synthesized in the liver from fatty acids as well as from proteins and glucose above the bodys current needs and then stored in fat cells. The levels vary, and are especially high after a meal. Even levels after fasting can change from day to day.
Some causes of elevated levels include:
Alcoholism
Diabetes out of control
Genetics
Pancreatitis
Hypothyroidism
Renal (kidney) failure
Some causes of decreased levels include:
Malabsorption
Malnutrition
http://www.labtestsonline.org/understanding/analytes/triglycerides/faq.html
Electrolytes
Potassium is a positively charged cation found mostly inside our cells. It is involved with water balance, ph balance, membrane transplant, and electrical conduction in the muscle and nerve cells. Potassium levels too high or too low may cause problems with our nerves and muscles. Some causes of elevated levels include:
Lab error (a common cause, due to red cells leaking potassium after they die)
High potassium diet (including certain fruits, substitute salt)
Renal (kidney) failure
Abnormal adrenal gland function (Addisonss disease and hypoaldosteronism)
Muscle injury
Dehydration
Diabetes
Fever
Breakdown of red blood cells
Lab error (a common cause, due to red cells leaking potassium after they die)
Diuretic drugs of a certain type (such as triamterene, spironolactone, amiloride)
ACE inhibitor drugs (the prils - lisinopril, benazepril, captopril, fosinopril and others)
ARB drugs (the sartans valsartan, losartan, olmesartan, irbesartan, others)
Anti-inflammatory drugs including Advil/ibuprofen, Aleve, many others
Beta blocker drugs
Some common causes of decreased levels include:
Diuretics of a certain kind, such as furosemide, and HCTZ (hydrochlorothiazide)
Diarrhea, vomiting and other causes of dehydration
Less common causes of low levels:
Abnormal adrenal gland function
Renal (kidney) disease
Malabsorption
Low magnesium
Laxatives
http://www.labtestsonline.org/understanding/analytes/potassium/glance.html
Sodium is a positively charged electrolyte found mostly outside cells. It is involved with water balance, pH (acid/base) balance, and nerve and muscle function. Its found in table salt, but blood levels are not usually related to salt intake.
Some common causes of elevated levels include (almost always due to excess fluid loss):
Dehydration
Vomiting
Some uncommon causes of high sodium:
Abnormal adrenal gland function (Cushing syndrome)
Congestive Heart Failure
Renal (kidney) failure
Too much salt intake with too little water intake
Inadequate levels of the hormone ADH
Some common causes of decreased levels include:
Loss of sodium diarrhea, excess sweating, diuretics
Abnormal adrenal gland function (Addisons disease)
Kidney disease
Some less common causes of low sodium:
Too much water intake
Congestive heart failure
Liver failure/cirrhosis
Diabetes
Thyroid Disease
Bowel Obstruction
Some brain and lung diseases with abnormal levels of hormone (ADH)
http://www.labtestsonline.org/understanding/analytes/sodium/glance.html
Other
Sedimentation Rate (Sed Rate) is a simple measure of how fast the red blood cells settle down to the bottom of a tube of blood. The cells settle faster when certain proteins are in the serum part of the blood. These proteins are elevated in infection and inflammatory conditions of the body. The elevated level of these proteins increase the sed rate. The sed rate is a very sensitive test, but not very specific. In other words it tells you something is going on, but not what that something is. (A related test is C-Reactive Protein). A normal sed rate, however, does not mean you do not have an inflammatory disease. In other words, a high sed rate is a useful test result; a normal or mildly elevated sed rate is not helpful. Some causes of elevated levels include:
Anemia
Arthritis
Infection
Autoimmune diseases like Lupus
Specific inflammatory diseases: temporal arteritis and polymyalgia rheumatica
Certain cancers, and especially multiple myeloma
Allergies
Old age
Pregnancy
Kidney failure
Certain drugs
Some causes of decreased levels include:
Congestive Heart Failure
Certain red blood cell diseases, including sickle cell anemia and polycythemia
http://www.labtestsonline.org/understanding/analytes/esr/glance.html
Mark Smith, MD
Dennis Oliver, MD
December 4, 2005
- - - Mark Smith, MD - - -
|
|
|
|
