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Blood Testing For Liver Disease

Most people believe that Liver tests only relates to an alcoholic wanting to know how bad his or her liver is damaged. Although this may be true, there are a multitude of reasons why one would want to order liver tests. It’s very common for physicians to order a liver profile to screen for injury, infection or disease. You may have heard the battery of liver tests called a Hepatic Function panel.  Many hepatitis patients as well as patients on chemo therapy require their livers to be monitored. The following is a list of tests that should be a part of a liver function assessment.
 
 
 
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) liver tests
·Liver enzymes that process amino acids
·Found inside healthy liver cells
·They are released into the blood when liver cells are damaged
·Primarily assess liver injury rather than liver function
·Mildly elevated ALT level (less than 1.5 times normal) could be normal for gender, ethnicity or body size
·May be normal in chronic hepatocyte injury (e.g., cirrhosis, hepatitis C)
·ALT is more accurate for determining liver damage
·AST is also released into the blood by: liver, heart, muscle, kidneys, brain, pancreas, lungs and blood cell
Liver·Elevated in: liver damage or failure; bile duct blockage; gallstones; some medicines; infections; inflammation of the liver
·Low in liver failure (after most liver cells are damaged and have released the enzymes)
 
Gamma glutamyl transferase (GGT)
·Liver tests enzyme that helps amino acids travel across cell plasma membranes
·Found in liver cells and cells of the bile duct walls
·Used to differentiate liver or bile duct disorders from bone disease
·Elevated in: bile duct damage or obstruction; gallstones; liver disease; some medicines; infections and inflammation of the liver; some metabolic diseases
·Low in liver failure (after most liver cells are damaged and have released the enzymes)
 
Alkaline phosphatase ("alk phos")
·An important enzyme in all cell types but has the highest concentration in bone, liver, intestines and placenta. Other liver tests are compared to this when evaluating.
·Elevated in: normal rapidly-growing children; bone disease or infection; thyroid disease; liver disease; bile duct obstruction; pregnancy; intestinal disease; diarrhea
·Low in: malnutrition; excess vitamin D intake
 
Bilirubin
·A normal byproduct of red blood cell recycling
·High Bilirubin levels cause jaundice (i.e., yellow skin color) or icterus (i.e., yellowing of the eyes)
·Can be measured as direct and indirect... or conjugated and uncongugated
·The conjugated and direct forms are more commonly associated with a liver-related problem
·The unconjugated and indirect forms are more commonly associated with excess blood cell destruction or recycling
·Elevated in: normal newborns (the newborn's liver takes a few days to "kick in"), excessive bruising or bleeding, infection, liver dysfunction, dehydration, breastfeeding infants, some metabolic diseases, some mild genetic conditions (i.e., Gilbert's syndrome)
·Low in: mildly low values are usually considered normal
 
Albumin
·A major blood protein that helps transport other molecules in the bloodstream. Many liver tests are based off of this result.
·Created by the liver
·A marker of liver function, but is affected by many other body processes
·Elevated in: mildly high values are usually considered normal
·Low in: liver disease, malnutrition, kidney disease, diarrhea, burns, trauma, surgery, infections, illness
 
Total protein
·Similar to albumin, but combines many different blood proteins (i.e., albumin, immunoglobulins, clotting proteins, etc.)
·Elevated in: autoimmune disorders, inflammation
·Low in: liver disease, malnutrition, kidney disease, diarrhea, burns, trauma, surgery, infections, illness
 
Ammonia
·The normal process of removing the amino group present on all amino acids produces ammonia
·Typically processed by the liver into urea, which can be excreted by the kidneys. In a liver tests profile, ammonia is a requirement.
·High ammonia levels cause confusion, seizures, sleepiness, clumsiness, and coma (when very high)
·Elevated in: lab error, blood cell damage, liver dysfunction or failure, metabolic disorders
·Low in: malnutrition, mildly low values are typically considered normal
 
Alpha fetoprotein (AFP)
·A protein normally produced during pregnancy
·Levels decrease soon after birth
·Probably has no normal function in adults
·Elevated in: normal pregnancy, liver tumors, other tumors
·Low in: a level of zero is normal in children and non-pregnant adults
 
Prothrombin time and INR
·Typically considered a measure of blood-clotting function
·One of the best measures of liver function, because the number increases quickly with poor liver function
·Elevated in: bleeding disorders, liver dysfunction, some medicines, vitamin K deficiency
·Low in: a mildly low level is typically considered normal
 
All of these liver tests are very common when evaluating the function of the liver.  All of these liver tests are performed on serum. When blood is allowed to clot, the serum is the clear fluid at the top of the clotted blood. Routine liver tests should be ordered at least once a year for all adults.