Screening for Elevated Liver Enzymes
Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are enzymes located in liver cells that leak out into circulating blood when liver cells are injured.
ALT and AST are found in other cells in the body, but their concentration is highest in liver cells. ALT and AST are also found in heart, skeletal muscle, and red blood cells. Statins, as well as certain nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics or antiseizure medications can cause elevated liver enzymes. These enzymes are often monitored in patients who are taking these medications.
What you can learn
This screening is a simple way for you to learn if your ALT/AST liver enzyme levels are in the desirable range, suggest possible liver damage, or suggest possible severe liver damage. You will want to share your results with your physician.
| Male¹ |
| |
|
Desirable Range |
Possible Liver Damage |
Possible Severe Liver Damage |
|
|
| ALT |
10-40 U/L |
>120 U/L |
>200 U/L |
| AST |
15-40 U/L |
>120 U/L |
>200 U/L |
|
 |
| Female |
| |
|
Desirable Range |
Possible Liver Damage |
Possible Severe Liver Damage |
|
|
| ALT |
7-35 U/L |
>105 U/L |
>175 U/L |
| AST |
13- 35 U/L |
>105 U/L |
>175 U/L |
|
|
AST/ALT Ratio* - AST/ALT >2.0 suggests possible liver damage (male or female)
¹ Wu AHB, ed. Tietz Clinical Guide to Laboratory Tests, 4th ed. St. Louis: W.B. Saunders Company 2006
What does my AST/ALT ratio mean?
The AST/ALT ratio is calculated by dividing your AST result by your ALT result. Unlike your actual ALT and AST levels, this number does not have a “desirable range.” Rather, it is used by your physician to differentiate liver damage from other organ damage as well as to monitor the severity of liver conditions.
Consult your physician for details.
Who should have it
This screening is for anyone who is on a cholesterol-lowering medication, such as a statin drug. ALT and AST are elevated in other conditions as well. Consult with your personal physician to see if you should be screened. Are you at risk? Find out.
How often to get screened
The American College of Cardiology, the American Heart Association and the National Heart, Lung and Blood Institute recommend monitoring ALT and AST levels in patients taking statins to lower cholesterol, initially to find out the baseline level, after 12 weeks of therapy, and then annually or more frequently if indicated. Your personal physician can determine how often you should be screened.
How to prepare
There is nothing you need to do in advance for this screening. Unlike other finger-stick blood screenings, this one does not require fasting beforehand.