New Liver Function Test Guidelines Updated by The American College of Gastroenterology

The American College of Gastroenterology has updated the guidelines for liver test to enable better diagnosis of liver diseases.

Highlights:

The American College of Gastroenterology has provided guidelines for liver tests for use by specialists as well as primary care givers.
There are 19 recommendations that have been provided which include the normal range for Alanine aminotransferase
There are stepwise algorithms for evaluating bilirubin levels, aspartate aminotransferase and abnormal ALT

The liver Function test guidelines have been updated by The American College of Gastroenterology (ACG). The revised recommendations on liver chemistry tests include

Specific ranges for normal alanine aminotransferase (ALT) levels
Stepwise algorithms which can be used for evaluating alkaline phosphatase, abnormal ALT, bilirubin levels and aspartate aminotransferase (AST).

The 19 recommendations were published in the American Journal of Gastroenterology and they cater to specialists as well as primary care providers. A thorough literature review was carried out to develop the guidelines with the help of previous ACG guidelines and policies were analyzed. In the absence of strong scientific evidence, the guidelines were based on a consensus opinion.

Normal ALT Levels

One of the significant aspects of the study is that normal ALT levels have been provided. The guidelines that were provided in the past included an upper limit of normal (ULN) that varied between organizations. They ranged from 30 to 40 IU/L (international units per liter) in certain hospitals to 70 or 80 IU/L in certain others.

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‘Updated liver test guidelines will aid in better diagnosis of liver disease.’

The current guidelines state that the normal ALT range should be between

19 - 25 IU/L for women
29 to 33 IU/L for men

The first author of the paper titled “ACG Clinical Guideline: Evaluation of Abnormal Liver Chemistries” Dr. Paul Kwo from The Stanford University Medical School said that the panel of experts who structured the guidelines recognized that lowered normal levels would mean more number of people would now receive results that were considered abnormal. There were concerns being raised that a lot of elevated liver test results would now crowd doctors. However, Dr. Kwo reiterated that there are numerous studies which showed that even innocuously elevated levels of ALT significantly increase the risk of liver related death.

Elevated Alanine Aminotransferase

The elevated ALT will aid in identifying people with

Chronic liver disease like nonalcoholic fatty liver disease
Chronic hepatitis C and B.

There are many therapies that are now available for conditions like chronic hepatitis C which could improve the condition of the liver. However, early identification is key, for which lowered levels of ALT could play a significant role.

Dr. Kwo further cautions that even a seemingly small increase in ALT which does not normalize after a considerable period of time requires further investigation. The lowered levels indicated in the guidelines will require clinicians a little time to get used to, but Dr. Kwo hopes that it will aid in identifying disease early and improve overall health of the liver.

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Elevated ALT and AST levels

There are algorithms provided in the guidelines for elevated levels of ALT and AST. They provide a graded evaluation method that categorize elevations as

mild
borderline
moderate
severe
massive

There are also provisions which state when there should be immediate evaluation in the event of elevated levels. There are algorithms for the evaluation of abnormalities in the bilirubin levels and in alkaline phosphatase levels, though there are not too many changes in these.

Other Significant Guidelines

The guidelines also include

Questions pertaining to medical history
Findings about physical examination
Recommendations for radiological and laboratory tests needed to conduct a liver biopsy
Guidelines for diagnostic testing for liver diseases, including autoimmune liver disease; viral hepatitis A, B, and C; nonalcoholic fatty liver disease; metabolic and genetic disorders that include hereditary hemochromatosis, Wilson's disease and alpha-1 antitrypsin deficiency
Guidelines for diagnostic testing for liver injury caused by

Herbal supplements
Prescription drugs
Over-the-counter drugs

Guidelines for Rare Diseases

The newly stated guidelines by The American College of Gastroenterology even include rare diseases like

Primary sclerosing cholangitis
Primary biliary cholangitis
Screening for celiac disease.
Disorders of striated muscle
Liver disorders of pregnancy
Lyme disease, which could be an uncommon reason for elevated liver tests

Change In Name

The guidelines state that instead of the name liver function test, it should henceforth be known as liver chemistry test or liver test. This is because the basic metabolic panels are indirect markers of liver function and not direct markers.

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Hepatocellular Injury

It is the disproportionate elevation of AST and ALT levels when compared to levels of alkaline phosphatase.

Cholestatic Injury

It is the disproportionate elevation of alkaline phosphatase level when compared to levels of AST and ALT.

An increase in conjugated bilirubin implies cholestasis or hepatocellular disease when unconjugated bilirubin is a major constituent of the circulating levels of bilirubin.

Dr. Paul Kwo stated that liver tests provide an important window into the overall health of an individual. The improved therapies that are available in this era for some liver diseases with probable options for other chronic liver diseases make it necessary to identify high risk patients and guide them to appropriate therapies. The guidelines provided will aid clinicians and other health care providers in providing the necessary support for correct diagnosis.

Reference:

Paul Y Kwo, Stanley M Cohen and Joseph K Lim. ACG Clinical Guideline: Evaluation of Abnormal Liver Chemistries. The American Journal of Gastroenterology. (2017) doi:10.1038/ajg.2016.517

Source-Medindia