American College of Gastroenterology has provided guidelines for liver
tests for use by specialists as well as primary care givers.
are 19 recommendations that have been provided which include the normal
range for Alanine aminotransferase
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
algorithms which can be used for evaluating alkaline phosphatase,
abnormal ALT, bilirubin levels and aspartate aminotransferase (AST).
recommendations were published in the American Journal of
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
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.
‘Updated liver test guidelines will aid in better diagnosis of liver disease.’
current guidelines state that the normal ALT range should be between
- 19 - 25 IU/L for
- 29 to 33 IU/L for
author of the paper titled "ACG Clinical Guideline: Evaluation of Abnormal
Liver Chemistries" Dr. Paul Kwo
from The Stanford University
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 ALT will aid in identifying people with
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.
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.
Elevated ALT and AST
algorithms provided in the guidelines for elevated levels of ALT and AST. They
provide a graded evaluation method that categorize elevations as
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.
guidelines also include
pertaining to medical history
- Findings about
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
Guidelines for Rare
stated guidelines by The American College of Gastroenterology even include rare
- 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
guidelines state that instead of the name liver function test, it should
henceforth be known as liver chemistry test
or liver test
is because the basic metabolic panels are indirect markers of liver function
and not direct markers.
It is the
disproportionate elevation of AST and ALT levels when compared to levels of
It is the
disproportionate elevation of alkaline phosphatase level when compared to
levels of AST and ALT.
increase in conjugated bilirubin implies cholestasis or hepatocellular disease
when unconjugated bilirubin is a major constituent of the circulating levels of
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.
- 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