Liver Blood Tests
Foreword
An initial step in detecting liver damage is a simple blood test to determine the presence of certain liver enzymes in the blood. Under normal circumstances, these enzymes in the liver cells. But when the liver injury, these enzymes are spilled out into the bloodstream.
Among the most sensitive and widely used of these liver enzymes are the aminotransferases. They include aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT). These enzymes normally contained within the liver cells. If the liver is injured, the liver cells spill the enzymes into the blood, raising the enzyme levels in the blood and marked liver damage.
Definition of the aminotransferases
Aminotransferases catalyze chemical reactions in cells in which an amino group is transferred from a donor molecule to a recipient molecule. Hence, the name "aminotransferases".
Sometimes medical terminology can be confusing, as the case of these enzymes. Another name for aminotransferase is transaminase. The enzyme aspartate aminotransferase (AST) is also known as serum glutamic oxaloacetic transaminase (SGOT) and alanine aminotransferase (ALT) also known as serum glutamic pyruvic transaminase (SGPT). To simplify it, AST = SGOT and ALT = SGPT.
In Normal, Where the presence of the aminotransferases?
AST (SGOT) is normally found in a variety of tissues including liver, heart, muscle, kidney, and brain. He is released into serum when any one of these tissues are damaged. For example, the level in serum rises with heart attacks and with muscle disorders. He is therefore not a highly specific indicator of liver injury.
ALT (SGPT), opposite to him, normally found largely in the liver. This is not to say that it is located exclusively in the liver but that he was there where he is most concentrated. He was released into the bloodstream as a result of liver injury. He therefore serves as a fairly specific indicator of the state (status) of the liver.
Rate-Normal Levels of AST and ALT
The normal range of values for AST (SGOT) is from 5 to 40 units per liter of serum (the liquid part of blood).
The normal range of values for ALT (SGPT) is from 7 to 56 units per liter of serum.
The Meaning Of the increase of AST and ALT
AST (SGOT) and ALT (SGPT) are sensitive indicators of liver damage from the types of different diseases. However, it must be emphasized that the levels of liver enzymes are higher than normal should not be automatically equated with liver disease. They may or they did not mean the heart problems. Interpretation (interpretation) of the levels of AST and ALT rise depends on the entire clinical picture and so it is best performed by a physician experienced in evaluating liver disease.
Appropriate levels of these enzymes do not correlate well with the extent of liver damage or prognosis. Thus, the levels of AST (SGOT) and ALT (SGPT) is appropriate can not be used to determine the degree of liver damage or predicting the future. For example, patients with acute hepatitis A virus may develop a level of AST and ALT-level very high (sometimes in the range of thousands of units / liter). However mostly patients with acute viral hepatitis A recover fully without residual liver disease. For an opposite example, patients with chronic hepatitis C infection typically have only a small increase of the levels of AST and ALT them. Some of these patients may have chronic liver disease that develops silently as chronic hepatitis and cirrhosis.
Disease-Heart Disease Causes Abnormal aminotransferase levels?
The levels of AST and ALT are found with the highest abnormalities that cause the death of many of the liver cells (extensive hepatic necrosis). It occurs in conditions such as hepatitis A or B virus, chronic liver damage clearly caused by toxins as from an overdose (overdose) of acetaminophen (brand name Tylenol), and the collapse of the old circulatory system (shock) when hearts deprived / deprived of fresh blood that carries oxygen and nutrients. The levels of serum AST and ALT in these situations can include anywhere from ten times the normal upper limits to the thousands of units / liter.
The increase in liver enzymes from mild to moderate is not unusual. They are often unexpectedly found in tests on a routine blood screening individuals who otherwise are healthy. The levels of AST and ALT in cases of this kind there are usually between twice the upper normal limits and a few hundred units / liter.
The most common cause of elevations of mild to moderate liver enzymes is fatty liver (fatty liver). In America, the cause of fatty liver is the most frequent abuse of alcohol. Other causes of fatty liver include diabetes mellitus and obesity (obesity). Chronic hepatitis C also is becoming an important cause of liver enzyme elevations are mild to moderate.
Medications that are causing abnormal aminotransferase levels?
A group of medications can cause liver enzyme levels are abnormal. Examples include:
* Drug-drug pain relievers such as aspirin, acetaminophen (Tylenol), ibuprofen (Advil, Motrin), neproxen (Narosyn), diclofenac (Voltaren), and phenybutazone (Butazolidine).
* Drug-drug anti-epileptic drugs such as phenytoin (Dilantin), valproic acid, carbamazepine (Tegretol), and phenobarbital.
* Antibiotics such as tetracyclines, sulfonamides, isoniazid (INH), sulfamethoxazole, trimethoprim, nitrofurantoin, etc..
* Cholesterol-lowering drugs such as "statins" (Mevacor, Pravachol, Lipitor, etc.) and niacin.
* Cardiovascular drugs such as amiodarone (Cordarone), hydralazine, quinidine, etc..
* Drug-drug anti-depression than tricyclic type.
With liver enzyme abnormalities caused by drugs, enzymes usually return to normal for weeks or months after stopping the drug.
What are the causes Less common Levels Of Abnormal aminotransferase
The causes are less common than abnormal liver enzymes in the United States include chronic hepatitis B, hemachromatosis, Wilson's disease, deficiency of alpha-1-antitrypsin deficiency, celiac sprue, Crohn's disease, ulcerative colitis, and autoimmune hepatitis. Although not as common as hepatitis C, hepatitis B can cause chronic liver disease with abnormal liver enzymes continued.
Hemachromatosis is a disorder of genetic (inherited) in which there is an excessive absorption of iron from food that leads to the accumulation of iron in the liver with liver inflammation and scarring that result.
Wilson disease is an inherited disorder with excessive copper accumulation in various tissues including the liver and brain. Copper in the liver can lead to chronic liver inflammation, where the copper in the brain can cause psychiatric disturbances and motor.
Deficiency Alpha-1-antitrypsin deficiency is an inherited disorder where deficiency of a glycoprotein (carbohydrate-protein complex) called alpha-1-antitrypsin leads to chronic lung disease (emphysema) and in liver disease.
Autoimmune hepatitis from the liver injury caused by antibodies and the body's own defense system attacks the liver.
Celiac sprue is a disease of the small intestine where a patient has an allergy to gluten (gluten in glutinous rice) and develop gas, bloating, diarrhea, and in cases of advanced malnutrition. Patients with celiac sprue can also develop the levels of ALT and AST abnormal light.
Crohn's disease and ulcerative colitis are diseases with inflammation of the intestines are chronic. In these patients liver inflammation (hepatitis) or bile ducts (primary sclerosing cholangitis) can also occur, causing liver tests are abnormal.
Rarely, abnormal liver enzymes may be a sign of liver cancer. Cancers that arise from cells called hepatocellularcarcinoma liver or hepatoma. The spread of cancers to the liver from other organs (such as colon, pancreas, stomach, etc.) is called metastatic malignancies (metastatic dangerous diseases).
Evaluating Healthy People For The Light To Moderate increase of aminotransferase levels?
Evaluation of healthy patients with abnormal liver enzymes need to be made individually. A doctor may ask for blood test data from the old records for comparison. If the old records are not available, the doctor may repeat blood tests in weeks to months to see whether these abnormalities remain valid. The doctor will look for risk factors for hepatitis B and C including sexual exposures, history of blood transfusions, injectable drug use, and exposure to work on blood products. A family history of liver disease may increase the likelihood of diseases that are inherited / derived as hemachromatosis, Wilson's disease, or deficiency of alpha-1-antitrypsin.
The pattern of liver enzyme abnormalities can provide useful clues on the cause of liver disease. For example, most of the patients with alcoholic liver disease have enzyme levels that are not as high as the levels achieved with acute viral hepatitis and AST ALT tended to be above. Thus, in alcoholic liver disease, AST is usually under 300 units / liter where the ALT is usually under 100 units / liter.
If alcohol or drugs are responsible for the abnormal liver-enzyme levels, stopping alcohol or drug (only under a doctor's supervision) should bring the enzyme levels to normal levels or near normal within weeks to months. If obesity is suspected as the cause of fatty liver, weight reduction of 5% to 10% should also bring the levels of liver enzyme levels to normal or near normal.
If abnormal liver enzymes remain in effect despite abstinence from alcohol, weight reduction and cessation drugs suspected of a certain blood tests can be performed to help diagnose diseases of the heart that can be treated. Blood can be tested for the presence of hepatitis viruses B and C and the antibodies they are related. Blood levels of iron, iron saturation, and ferritin (another measurement of the amount of iron stored in the body) is usually elevated in patients with hemachromatosis. Blood levels of a compound called ceruloplasmin is usually reduced in patients with Wilson's disease. Blood levels of certain antibodies (anti-nuclear antibody or ANA, anti-smooth muscle antibody, and anti-liver and kidney microsome antibody) increased in patients with autoimmune hepatitis.
Ultrasound and CAT scan of the abdomen is sometimes used to remove or eliminate tumors in the liver or other conditions such as gallstones or tumors that block the ducts that drain the liver.
Liver biopsy is a procedure where a needle is inserted through the skin over the right upper abdomen to obtain a thin strand of liver tissue for examination under a microscope. The procedure is often performed after ultrasound study was to localize the liver. Not every person with abnormal liver enzymes need a liver biopsy. The doctor will usually recommend this procedure if 1) the information obtained from liver biopsy will probably be useful in planning treatment, 2) the doctor needs to know the extent and severity of inflammation / liver damage, or 3) to evaluate the effectiveness of treatment.
Liver biopsy is most useful in confirming a diagnosis of a condition that can be treated potentially. Liver diseases that have the potential to be treated include chronic hepatitis B and C, hemachromatosis, Wilson's disease, autoimmune hepatitis, and deficiency of alpha-1-antitrypsin.
What is usually most useful is the test of serial (consecutive) of AST (SGOT) and ALT (SGPT) through time to determine whether the level-level rise, remain stable or fall. For example, patients who underwent treatment for chronic hepatitis C should be monitored by liver enzyme tests series. Those who respond to treatment will experience a decrease in liver enzyme levels to normal levels or normal closer. Those who experience recurrent hepatitis C after completion of treatment will usually develop liver enzyme levels of abnormal return.
Other Enzymes-Liver Enzyme
Besides, AST and ALT, there are other enzymes including alkaline phosphatase, 5'-nucleotidase ("5 prime" nucleotidase), and gamma-glutamyltranspeptidase (GGT) are often tested for liver disease.
We have limited the consideration of liver enzymes AST and ALT are at because they are biochemically related to each other and, more importantly, they are two enzymes that are most useful.
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