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(Established in March 1996)
Dr. Wu's Liver diseases
| Transaminase: GOT (AST), GPT (ALT)|
for professionals (medical students and residents) and consumers
(Posted Sep. 16, 1996; Updated May 14, 2009)
- GOT (Glutamyl oxaloacetic transaminase)
- GPT (Glutamyl pyruvic transaminase)
- AST (Aspartate aminotransferase)
- ALT (Alanine aminotransferase)
- One of the thousands kinds of liver enzymes, and a kind of transferase.
- Having the function of transfering amino group of amino acids
from alpha-amino acids to alpha-keto acids, therefore, named transaminase.
- L-Aspartic Acid + Ketoglutaric Acid ¡÷ Oxaloacetic Acid + L-Glutaric
- L-Alanine + Ketoglutaric ¡÷ Pyruvic Acid + Glutaric Acid
- Storage mostly in liver etc.
- Low serum concentration.
- Large amount of transaminase is released into blood mostly on
liver cell damages.
- Thus, detection of serum level tells the existence of liver cell
Elevation of the serum level:
Determination of serum transaminase:
Objects and usefulness
- Of use in detection of asymptomatic stage in liver disease as:
preicteric stage of hepatitis.
- Of use in detection of anicteric liver disease.
- Useful in evaluation of the course of liver disease.
- Determining factors of serum levels:
- Tissue concentration of transaminase.
- Extent of tissue damages.
- Capability of release of enzyme from the tissues.
- Half life of the transaminase in the blood.
Reference value: (depends on methods)
- Karmen method: 10 ~ 26 KU
- Reitman-Frankel method: 7 ~ 20 KU
- JSCC, IFCC: 15 ~ 40 IU/L
- Karmen method: 3 ~ 18 KU
- Reitman-Frankel method: 2 ~ 17 KU
- JSCC, IFCC: 8 ~ 30 IU/L
- Immuno-absorption method: < 4 KU
- (The result may be expressed with IU, international unit)
- KU/IU: 1.35 ~ 1.58 (depend on methods)
- As serum GOT is below 30 KU and GPT 25 in 90 % of healthy persons,
we usually assume 40 IU for GOT and 35 IU for GPT as their upper
limits of normal.
- GOT/GPT: (depends on method, 0.7 ~ 1.4):1 by Karmen method, 0.87
- Age influence:
- GOT: lowest under the age of 20 years for both sexes, thereafter,
increases with the increase in age.
- GPT: highest at the ages of 30 ~ 40 years for male, and 50 ~ 60
years for female.
- No influenced by food.
- Increase after exercise.
- Increase in hemodialysis, and GOT > GPT.
- Preservation of specimens:
- Rather stable with GOT.
- At 4¢J, with little change for one week.
- Under freezing, no change for one month.
- GPT is somewhat unstable than GOT.
- At 4¢J, stable for only 3 ~ 4 days.
- Under freezing: without change for 2 weeks.
- With higher concentration of the serum level, it shows rather
unstable effect, thus it is advised to make the test on the day
when the blood is drawn, and even the serum is kept frozen , the
test should be done within 5 days after blood is obtained.
Abnormality of serum GOT and GPT:
A) Hepatobiliary diseases:
1) Acute hepatitis:
- Whatever the etiological factors is, when there is liver cell
injuries, there will be of increase in serum transaminase levels.
- At the onset, the serum level may increase up to as high as
300 ~ 3,000 units.
- Sometimes, the level may as high as over 3,000 units, however,
it is around 500 ~ 1,500 units in most of the cases.
- Even in the absence of jaundice, the level may rise high up to
over 1,000 units.
- When a test is done immediately after the onset, the level of
GOT is usually higher than GPT.
- After the peak stage (usually, one week after the onset of symptoms),
the level of GPT will be greater than GOT (GPT > GOT).
- In general practice, the serum GPT level is usually greater than
GOT and below 1,000 units at the first test on consultation, because
the patients usually consult with the physician more than one
week after the onset of symptoms.
- Moreover, the serum transaminase level might have lowered to the
level of within normal range, thus the physician often hesitate
to make the diagnosis of hepatitis.
- Histopathological change of acute hepatitis will be observed on
the liver biopsy examination in spite of the normal serum transaminase
level for these cases.
- In typical course of acute hepatitis cases, the serum transaminase
will recover to the normal range within 6 ~ 10 weeks.
- In cases with serum transaminase level rises and falls between
100 ~ 300 units for more than three months, chronic hepatitis
should be considered.
- In acute hepatitis, change of serum GOT and GPT is great and rapid
during the first 10 days after the onset of symptoms. At the time
of onset of jaundice, the levels of serum GOT and GPT have already
begun to decrease, therefore, when the patient presenting with
the symptoms suspicious of the possibility of hepatitis, you should
test the blood for serum transaminase, because if you draw blood
a few days later, the serum transaminase might have decreased
and be difficult to be used as the marker for diagnosis of hepatitis.
- For instance, it is not uncommon that the patient consults the
physician on Saturday, however, the drawing of blood is delayed
until next Monday because of weekend, and as a result the serum
transaminase level may have dropped to the level of below 200
units, which confuses you to make a differential diagnosis between
hepatitis and obstructive jaundice.
- At times, in a case of fulminant hepatitis, the serum transaminase
level may have already dropped to the level of normal range on
presentation, which may mislead physician to the diagnosis of
ordinary acute hepatitis but not a fulminant hepatitis.
- The large amount of transaminase released to the blood stream
in a case of fulminant hepatitis is removed from blood in a few
days, and the massive necrosis caused few intact liver cells remained
to supply as the source of serum transamninase.
(2) Chronic hepatitis:
- In the cases of mild chronic hepatitis (chronic persistent hepatitis),
serum transaminase usually fluctuates below the level of 100 units.
- In the cases of moderate to severe chronic hepatitis (chronic
active hepatitis), serum transaminase fluctuates between 100 ~
- Normal serum transaminase level does not always mean no active
inflammation of the liver cells. It is not uncommon that active
chronic hepatitis will be observed on histopathlogical examination.
- It is common that when a case of chronic hepatitis without subjective
symptoms presenting himself with symptoms, serum transaminase
level could be as high as over 1,000 units, thus it is impossible
to differentiate between an acute hepatitis and an acute exacerbation
of chronic hepatitis by the extent of rise in the level of serum
(3) Cirrhosis of the liver:
- Serum transaminase usually fluctuates persistently in the range
of below 100 IU.
- In cases of cirrhosis associated with the active chronic hepatitis,
the serum transaminase level will be higher than those without
active chronic hepatitis. Its range is the same as that of active
- Usually, the serum GOT level is 5 ~ 6 times greater than serum
GPT in cirrhosis patients. Therefore, it is often difficult to
make differential diagnosis with a case of acute myocardial infarction
without typical symptoms.
- The dissociation between GOT and GPT is explained as due to more
highly differentiated GPT than GOT, which caused the more difficulty
in synthesis of GPT than GOT owing to the circulatory failure
in cirrhosis of the liver.
- The degree of elevation of GOT and GPT is unrelated to the extent
of cirrhosis but related to the degree of the active inflammation
of the liver.
- In the presence of active piecemeal necrosis in the periportal
area and progressive infiltration of chronic inflammatory cells
and liver cell damages in the hepatic lobules, the elevation of
serum transaminase keep mild to moderate degree of elevation.
(4) Alcoholic liver disease:
- In alcoholic fatty liver and cirrhosis of the liver, there will
be of 75 % of the cases with elevation of serum GOT and GPT. In
cases of fatty liver, the degree of elevation is usually below
100 IU, and in cases of cirrhosis, usually resembles to that of
the cases of viral origin.
- In the cases of acute alcoholic hepatitis, around 95 % of the
cases will show higher elevation of GOT and GPT, and it may be
high up to 300 IU.
- In alcoholic liver disease, the ratio of GOT/GPT ratio is usually
higher than 2, therefore in case with GOT/GPT ratio greater than
2, we should consider the possibility of alcoholic liver disease.
- It is explained as the result of decrease in pyridoxal-5'-phosphate,
which is depressed in alcoholic liver disease, because pyridoxal
plays an important role in the aminoacids metablolism (i.e. synthesis
of transaminase), and GPT depends more on pyridoxal than GOT for
- It is also explained as the result of release of GOTm (mitochondrial
GOT) from the liver cells around the central vein. In alcoholic
liver disease, more liver cells around the central vein than peripheral
region of the hepatic lobules are damaged, and more GOTm is present
in the cells of this region.
- In my experience, among 32 cases of chronic alcoholics, the average
serum GOT level is 134 IU, and GPT 50 IU, the highest values are
900 and 200 IU for GOT and GPT, respectively.
(5) Tumor of the liver (benign and malignant):
- All tumor lesions including malignancy of the liver (primary and
metastatic) and localized liver lesion such as liver abscess show
non-specific elevation of serum transaminase.
- May elevate up to 300 IU and usually GOT is greater than GPT.
- The elevation of serum GOT and GPT is mostly owing to the release
of the enzymes from the surrounding liver cells due to the increasing
pressure from the growing mass, and partly released from the malignant
- In Taiwan, 80 % of the hepato-cellular carcinomas are arising
on the basis of cirrhosis, therefore the elevated serum GOT and
GPT reflect the active inflammatory process of the underlying
(6) Biliary tract diseases:
- In the cases with lesions limited in the gall bladder and without
the involvement of bile ducts such as: cholecystitis, gall bladder
stone and tumor of the gall bladder, not only serum GOT and GPT,
but also the other liver related enzyme tests will be in the range
- In cases with involvement of bile ducts such as: cholangitis,
obstruction due to stone, tumor or parasite, the serum GOT and
GPT will be of mild to moderate degree of elevation, rarely over
300 IU, and GOT is usually greater than GPT. The elevation above
300 IU is exceptional.
(B) Cardiac diseases:
- Except for in the cases of hepato-biliary diseases, the elevation
of serum GOT will be observed in the diseases of heart and striated
muscle, however, no concomitant elevation of GPT will be noted.
- Myocardium contains the same concentration of GOT as that of the
liver, therefore, in case of injury to the myocardium as in the
acute myocardial infarction, the GOT released from the damaged
myocardium makes serum GOT elevated. The ratio of GOT concentration
in the serum and myocardium is 1: 7,800, and the volume of serum
in an adult is about 2,000 cc, thus even only 0.25 gm of myocardium
had the damage, it would double the serum concentration of GOT
but not GPT.
- In typical case of acute myocardial infarction, serum GOT would
rise 6 ~ 12 hours after the onset of attack, and reaches the highest
level in 24 ~ 48 hours after the onset. This elevation would recover
to within normal range in 3 ~ 5 days after.
- In acute myocardial infarction, the serum GOT rarely exceed the
level of 500 IU.
- In patients with cardiac symptom associated with elevation of
GOT more than 500 IU and also accompanied by elevation of GPT,
a right heart failure or shock state should be considered.
- Because, the cardiac disease has quite distinct clinical symptoms,
the differential diagnosis seldom becomes a problem.
(C) Striated muscle diseases:
- In striated muscular diseases as: polymyositis, progressive muscular
dystrophy and dermatomyositis, increase in serum GOT is observed.
- Only increase in serum GOT is observed, but not associated with
concurrent increase in serum GPT.
- Serum creatine phosphokinse (CPK) increases markedly in striated
muscular diseases, but no increase of CPK is observed in liver
diseases, this observation usually makes the differential diagnosis
- In shock state, a large amounts of GOT and GPT are released to
the blood stream due to the central necrosis of the hepatic acinus.
- Elevation of serum GOT may be induced from hemolytic diseases
and hemolysis due to any causes.
- GPT is contained only in cytosol of cells, but GOT present in
both cytosol and mitochondria of the cells, therefore, there are
two sorts of GOT, i.e. GOTm (mitochondrial) and GOTs (supernatant).
- Only GOTs is released, when only degeneration or changes in permeability
of the liver cell membrane occur, however, when massive necrosis
of the liver occur, there will be of release of a large amount
of GOTm into the blood stream from the destructed liver cells,
therefore, by determination of ratio of serum GOTm and GOTs, the
degree of liver cell injuries will be estimated.
- In alcoholic liver disease, the liver cell necrosis occurs mostly
in the perivenular region where GOTm is abundant, therefore, a
remarkable increase of GOTm will be noted in alcoholic liver disease.
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(By Jau-Shin Wu, M.D.; Posted Sep. 16, 1996; Revised May 12, 2009)
(TMN) Since June 09, 2002
(Dr. Wu's Liver D) Since Jan. 01, 2008
(Olddoc)Since Jan. 01, 2008
(TMN) Since Jan. 01, 2008