SGOT (Aspartate aminotransferase)

What sample is needed for SGOT (Aspartate aminotransferase)?

1. This is done on the patient’s serum.
2. A random sample can be used.
3. The serum is stable for 24 hours at room temp. And 28 days at 4 °C.

What are the precautions for SGOT (Aspartate aminotransferase)?

1. Avoid hemolysis because RBC contains AST and ALT, which will increase the value.
2. Avoid any I/M injection, which will increase the SGOT level.
3. Pregnancy may cause a decrease in the AST level.
4. Exercise may increase the AST level.
5. Another source of error is increased ALT and AST levels after exercise.
6. Alcohol use will affect the result.
7. It is increased due to calcium dust in the air, like construction in the laboratory.
8. False decreases occur in diabetic ketoacidosis, severe liver disease, and uremia.
9. There is a false decreased level in:
   1. Pyridixoin deficiency (Beriberi).
   2. Severe long-standing liver diseases.
   3. Uremia.
   4. Diabetic ketoacidosis.
10. Drugs that may increase their value are:
    1. Antihypertensive.
    2. Digitalis preparation.
    3. Erythromycin.
    4. Anticoagulants like coumarine.
    5. Oral contraceptives.
    6. Isoniazid.
    7. Salicylates.
    8. Opiates.
    9. Hepatotoxic drugs.
    10. Methyldopa.
11. SGOT is decreased because of the increased serum lactate-consuming enzyme during the test, as seen in diabetic ketoacidosis, Beriberi, severe liver disease, uremia, and chronic hemodialysis.

What are the Indications for SGOT (Aspartate aminotransferase)?

1. This is done in suspected liver diseases.
2. This also helps in diagnosing acute myocardial infarction (heart disease).
3. It helps in D/D of AMI and liver disease.
4. It is advised in the case of blood donors for hepatitis.

How will you define aspartate aminotransferase (SGOT)?

1. Aspartate transaminase is also known as L-aspartate-2-oxoglutarate aminotransferase, AST.
2. This enzyme catalyzes the reversible transfer of amino groups between an amino acid, and α-keto acids are called aminotransferase or transaminases.

3. One of the aminotransferases is Aspartate aminotransferase (AST), or the old name was glutamic -oxaloacetic transaminase (GOT).
4. SGOT shows day-to-day variation ≤10%
5. It is widely distributed in tissue, with the highest concentration in the heart, liver, and skeletal muscles.
6. SGOT’s lowest concentration is in the kidneys, pancreas, and RBCs.

What is the distribution of the SGOT (AST) in the body?

1. This enzyme is distributed in all tissues (primarily all the tissues), but the highest concentration is found in the liver, heart, and skeletal muscles.
   1. AST (SGOT)  concentration is more in the heart >liver> muscles>kidneys>pancreas.
2. According to concentration, SGOT is found in descending order:
   1. Cardiac muscle.
   2. Liver.
   3. Skeletal muscles.
   4. Kidney.
   5. Brain.
   6. Lungs.
   7. Pancreas.
3. High concentration was seen in the cardiac muscle and liver.
   1. Intermediate concentration in skeletal muscle and kidneys.
   2. Much lower level in other tissues.
   3. Minimal activity (small amount) occurs in the skin, kidneys, pancreas, and RBCs.
   4. SGOT is found in plasma, bile, CSF, and saliva.
   5. It is not found in urine unless there is a kidney lesion.
4. This enzyme exists in two isoenzyme fractions:
   1. In the liver, it is present in the cytosolic (cell cytoplasm), and the second form is mitochondrial.
   2. The intracellular concentration of the SGOT enzyme is 7000 times as compared to the extracellular concentration.
   3. The cytoplasmic fraction isoenzyme is predominant in the serum.

SGOT (Aspartate aminotransferase): Distribution of the SGOT in the liver cell

5. AST and ALT are increased at birth to 2 to 3 times the adult level; this will fall to the adult level by 2 to 4 months.
6. Compared to serum, the SGOT level is 7800 times in the heart, 7100 times in the liver, skeletal muscles 5000 times, kidney 4500 times, pancreas 1400 times, spleen 700 times, lungs 500 times,  and RBCs 15 times.

SGOT (AST) level in various tissues as compared to the serum (one unit):

What is the mechanism of Liver cell Injury?

1. The injury to liver cells leads to the release of the SGOT into the blood circulation and causes an elevation in the SGOT level.
2. SGOT is present in the cytoplasm and the mitochondria.
3. In the blood, there is cytosolic and mitochondrial SGOT (AST).

4. After the injury, SGOT (AST) rises in the blood for around 8 hours, and the peak level is 24 to 36 hours and returns to normal in 3 to 6 days.
5. In the case of minor injury, the SGOT (AST) level only rises transiently, and this may not be noticed.
6. In Acute viral hepatitis, there is a rise >10 times the normal in 75% of the cases in one study and 100% in another study.

SGOT (Aspartate aminotransferase): The release of the SGOT depends upon the number of hepatocytes damaged.

How will you define SGOT (AST) biochemical reaction?

1. AST catalyzes the biochemical reaction, and it is reversible.
   1. The P-5-P is bound to the apoenzyme and is a true prosthetic group.
   2. The P-5-P bound to the apoenzyme accepts the amino group from the first substrate, aspartate, to form enzyme-bound pyridoxine-5- phosphate, and the first reaction product is glutamate. Pyridoxal-5‘- phosphate  (P-5-P) functions as coenzymes in the amino-transfer reaction.

How will you differentiate SGOT (AST) and variations in different conditions?

What causes SGOT levels to be 1.5 to 8 times more than normal?

1. Early, late, and subclinical viral hepatitis.
2. Chronic hepatitis.
3. Alcoholic hepatitis.
4. Hepatitis due to chemicals.
5. Reye’s syndrome.
6.  Cholangitis
7. Passive congestion with centrilobular necrosis.

What causes SGOT level to be >8 to 10 times more than normal?

1. Acute viral hepatitis.

What causes the SGOT level to be >30 times higher than normal?

1. Alcoholic patients are taking acetaminophen.
2. In acute extrahepatic obstructions like gallstones, the SGOT level rises to 10 times the normal value and normally returns quickly when the obstruction is relieved.

What is the Distribution of SGOT (AST) in various diseases?

What is the diagnostic application of SGOT?

1. It is released into circulation and can diagnose the following conditions:
2. In liver diseases:
   1. The level may reach 100 times above the normal limit.
   2. In cirrhosis, there is a moderate increase, which may be around 4 times the normal limit.
   3. The amount of SGOT is directly related to the number of cells affected by the disease or injury.
   4. In chronic injury, the elevated level will persist.
   5. In Acute hepatitis, the level may increase 20 times than normal.
3. Heart diseases:
   1. After congestive heart failure, there is a rise in the SGOT level due to less blood supply to the liver.
   2. There is a rise after 6 to 8 hours of myocardial infarction damage or chest pain. Abnormal values are seen almost in more than 97% of the cases.
   3. This test is advised in hepatocellular diseases and coronary occlusive diseases leading to muscle necrosis.
4. Skeletal muscle diseases:
   1. This is seen in muscular dystrophy and inflammatory conditions, which may reach  4 to 8 times the normal value.
5. Renal infarction.
6. Brain infarction.
7. There is an elevation in pulmonary embolism.

What are the conditions where you will see an AST/ALT ratio, usually >1?

1. The patient with alcoholic cirrhosis.
2. Liver congestion.
3. Metastatic tumor of the liver.

What conditions will you see an AST/ALT  ratio of <1?

1. Acute hepatitis.
2. Viral hepatitis.
3. Infectious mononucleosis.
4. The ratio will be less accurate if the AST level is more than 10 times normal.

What is the normal SGOT (Aspartate aminotransferase) level?

Source 1

Source 2

• Newborn/ infants  = 15 to 60 units/L
• Child = Value like an adult
• Adult = 0 to 35 units/L

Elderly = Slightly higher than the adults

Source 4

• Men = 14 to 20 U/L  (0.23 to 0.33 µKat/L).
• Women = 10 to 36 U/L  (0.23 to 0.33 µKat/L).
• Newborn = 47 to 150 U/L  (0.23 to 0.33 µKat/L).
• Children = 9 to 80 U/L  (0.23 to 0.33 µKat/L).

Another source

• Newborn = 25 to 75 U/L
• Infants = 15 to 60 U/L
• Adult
  • Male = 15  to 40 U/L at 37C.
  • Female = 13 to 35 U/L at 37C.
  • Elderly = slightly higher than the adult.
• SGOT > 450 U/L in blunt abdominal injury is an indicator of liver injury.

Source 6

What are the causes of increased SGOT (Aspartate aminotransferase)?

1. Fulminant type of hepatitis, especially viral type.
2. In liver cell necrosis or injury like chronic hepatitis.
3. Alcoholic hepatitis.
4. Cirrhosis depends upon the cell’s activity.
   1. In inactive cirrhosis, usually AST level is normal.
   2. In active cirrhosis, the AST level is mild to moderately raised. AST level is <5 times the upper limit; in 95% of cases, the upper limit is <10 times the normal value.
   3. One study showed that in 15% of cases, the upper limit was >10 times the normal, possibly due to superimposed virus infection.
5. Cholestatic and obstructive jaundice.
   1. There is no rise in the enzyme unless there is secondary damage to the liver tissue.
   2. The elevation is mild to moderate, <10 times the normal value.
   3. When the obstruction is extrahepatic, AST rises rapidly to >10 times the normal level and falls rapidly after 72 hours.
6. Liver metastasis and Hepatoma (increase maybe 5 to 10 folds and is of both enzymes).
   1. Around 50% of the liver’s metastatic infiltrate shows a <5 times increase in the AST level.
7. In necrosis of heart or skeletal muscle, e.g., acute myocardial infarction.
8. In infectious mononucleosis, AST is raised in 88% to 95% of cases. Only 5% of the patients show >10 times the normal value.
   1. 2% may show >20 times the normal value.
9. Severe exercise.
10. Severe burn.
11. Hypothyroidism ( in 40 to 90% of cases).
12. A transient increase in acute pancreatitis, acute renal diseases, musculoskeletal diseases, or trauma may occur.
13. Other diseases than liver and heart can increase the level:
    1. Hypothyroidism.
    2. Dermatomyositis.
    3. Polymyositis.
    4. Gangrene.
    5. Toxic shock syndrome.
    6. Shock.
    7. Mushroom poisoning.
    8. Pulmonary embolism and infarction.
    9. Hemolytic anemia.
    10. Malignant hyperthermia.

What are the causes of a raised level of SGOT (AST)?

What are the causes of decreased SGOT (Aspartate aminotransferase) levels?

1. Chronic renal dialysis.
2. Acute renal diseases are leading to Azotemia.
3. Vit.B6 deficiency.
4. Beriberi.
5. Pregnancy.

What will the enzyme pattern be in Acute Myocardial infarction (AMI)?:

1. The SGOT level will be raised, but this is not a specific test but useful when there is a raised level of Creatine phosphokinase(CPK) and Lactic dehydrogenase(LDH).
2. In Myocardial Infarction:
   1. SGOT appears in 6 to 8 hours after the onset of chest pain. This rise is 3 to 5 times normal.
   2. The peak level is between 18 to 24 hours.
   3. Returns to normal in 4 to 6 days unless there is no new infarct.
      1. The average increase in MI is 4 to 5 times normal.
      2. The increase of 10 to 15 times indicates massive MI (fatal infarcts).
      3. If the test is done at the right time, the abnormal level is seen in more than 97% of patients.

3. A myocardial injury like Angina, pericarditis, and rheumatic carditis does not rise in level.
4. The small increase in the SGOT level does not indicate a favorable prognosis.
5. ALT (SGPT) is usually within normal limits, or rarely only marginally increased, in uncomplicated myocardial infarction because of the small amount of ALT activity in the heart muscles.

What will the pattern of SGOT (Aspartate aminotransferase) be in liver diseases?

1. There is a raised level of SGOT in liver cell necrosis, which may be a 10 to 100-fold increase.
   1. 20 to 50 times, elevations are frequent.
   2. Peak values are seen on the 7th or 12th days.
   3. Then, the activity decreases, and in case of uneventful recovery, the normal level is reached by the 3rd to 5th week.
   4. SGOT (AST) is also raised in toxic hepatitis, like infectious hepatitis.
2. The SGOT level may be compared with SGPT.
3. The SGOT/SGPT ratio is usually greater than 1 in a patient with alcoholic cirrhosis, liver congestion, and metastatic tumors of the liver.
   1. A ratio of <1 may be seen in acute hepatitis and viral hepatitis.

Acute viral hepatitis:

What is the pattern of SGOT in acute viral hepatitis?

1. The rise of SGOT was seen before the onset of jaundice.
2. Peak level has been seen from 7 to 12 days after the onset of jaundice.
3. The normal level has been seen  3 to 4 weeks after the onset of jaundice.
4. Characteristically, SGPT is greater than SGOT.

What will the level of SGOT be in various conditions?

• Critical value: >20,000 U/L seen in alcohol-acetaminophen syndrome.

How will you define the AST (SGOT)/ALT (SGPT) ratio?

1. AST (SGOT) is present in liver cells, microsomes, and mitochondria.
2. ALT (SGPT) is present in the liver microsomes.
3. In the case of severe necrosis, AST (SGOT) increases more than ALT (SGPT), but in liver cells with inflammation without much necrosis, ALT (SGPT) increases more than AST (SGOT).

What are the indications for the AST/ALT ratio?

• AST/ALT ratio differentiates between the hepatobiliary system and pancreas.

What is the normal AST/ALT ratio?

• 0.7 to 1.4 (Depending upon the methods).

What are the causes of the raised AST/ALT ratio?

1. Drug toxicity (>2.0).
2. Alcoholic hepatitis (>2.0).
3. In the case of cirrhosis (1.4 to 2.0).
4. Hepatocellular carcinoma.
5. Intrahepatic cholestasis (>1.5).
6. In the case of chronic hepatitis, there is a slight increase (1.3).

What are the causes of decreased AST/ALT ratio?

1. Extrahepatic cholestasis (normal or slightly decreased).
2. In the case of acute hepatitis due to drugs, viruses, and toxins.

What are the facts about SGOT and SGPT?

1. AST (SGOT) is always raised in acute myocardial infarction, where ALT (SGPT) will be normal unless there is damage to the liver.
2. ALT  (SGPT) is more raised in acute hepatobiliary obstruction than AST (SGOT).
3. ALT (SGPT) is more specific than AST (SGOT) for liver cell injury.
4. AST (SGOT) is more sensitive to alcoholic liver cell injury.

Questions and answers: