When your liver is diseased or injured, your body releases tell-tale enzymes that your doctor can measure through tests. Many conditions unrelated to the liver can cause abnormal results, however. For example, some gallbladder treatments that contain cholesterol can elevate your liver enzymes. Moreover, a mechanism that controls the production of cholesterol in your liver is also the same mechanism responsible for the scarring process that leads to the release of enzymes.
Cholesterol-Enzyme Connection
Your liver is a dynamic organ. In addition to sending you enzymatic signals that there's trouble, your liver also produces cholesterol. In March 2011, UCLA researchers wrote that a mechanism that regulates the production of cholesterol -- liver X receptors -- also plays a role in the development of scar tissue in the liver in the face of injury. This is a way that cholesterol production may also elevate liver enzyme counts. The liver has the ability to regenerate its own tissue. When injured, it creates this scar tissue to essentially cut off the working parts and preserve healthy, working tissue. As it continues to face injury or disease, however, this scar tissue continues to spread.
Moreover, some cholesterol-lowering drugs such as statins work by blocking the work of other liver enzymes involved in cholesterol production. Some gallbladder treatments are made from bile. Taking them can increase your cholesterol as well as some liver enzymes.
ALT and AST
Alanine transaminase, or ALT, is found in its highest concentrations in your liver. Injury to your liver causes ALT to be released into your bloodstream. Normal levels vary, but if your doctor tells you have an abnormal reading, your risk of cirrhosis, death of liver tissue, hepatitis or liver cancer might be increased, according to MedlinePlus. Aspartate aminotransferase, or AST, is another enzyme found in high amounts in your liver. MedlinePlus says it's normal to have a reading of 10 to 34 IU/L, and the same liver diseases will cause an increase in AST level.
Albumin, A1AT and ALP
A serum albumin test is a way your doctor can detect the amount of this liver-produced protein. A normal range is 3.4 to 5.4 g/dL, according to MedlinePlus. Low levels of albumin could be a sign of liver disease. A blood test known as alpha-1 antitrypsin picks up on liver cirrhosis caused by an inherited deficiency in the substance. Normal ranges vary so your doctor is the best person to tell you how to read the results. Akaline phosphatase, or ALP, is a protein enzyme found in high amounts in liver tissue. It has a counterpart that exists in your intestine whose job it is to break down dietary cholesterol. The ALP enzyme often occurs simultaneously with elevated cholesterol levels. When your results fall outside the normal range of 44 to 147 IU/L, you may need additional testing for hepatitis or other liver diseases.
GGT
If you have a lack of blood flow to your liver, a gamma-glutamyl transpeptidase, or GGT test might pick up on it. MedlinePlus says a normal range for this substance in your blood is from 0 to 51 IU/L. Liver disease might also increase the time it takes for your blood to normally clot, so a prothrombin time can track this, with normal time being 11 to 13.5 seconds.
Blood and Urine Bilirubin
Your liver produces a substance called bile, which helps in digestive processes. It contains a yellow pigment called bilirubin. It's actually colored waste product that naturally result when red blood cells die . Excessive bilirubin can lead to jaundice, which indicates that a bile duct has been blocked, possibly by a liver disease. A normal range for total bilirubin is from 0.3 to 1.8 mg/dL, according to MedlinePlus.
References
- MedlinePlus: Liver Function Tests
- British Liver Trust: Liver Function Tests
- University of California Los Angeles; Cholesterol Regulator Key in Liver Scarring, Cirrhosis; March 30, 2011
- University of Maryland Medical Center: Cholesterol - Medications
- American Liver Foundation: Liver Foundation Tests
- National Digestive Diseases Information Clearinghouse; Gallstones; July 2007
