Aspartate aminotransferase (AST or GOT) is an enzyme found mainly in the liver and kidneys. The feedback from High AST in the context of high transaminases is indicative for the presence of a damage hepatic.
Normally, there are fairly low values of AST in the blood. The finding of a AST increase, and transaminases in general, is an indication of the presence of an insult that is causing damage to the liver.
AST, along with ALT, is also used to detect and / or monitor acute or chronic liver disease. Aspartate aminotransferase (also called AST, GOT or GOT) is usually measured in conjunction with another transaminase, alanine aminotransferase (also called ALT, GPT or GPT) as part of a "package" of tests that target to evaluate liver function, to determine the origin and extent of any liver tissue damage.
What is AST or GOT
What are the transaminases? what is that the AST? AST is one of the transaminases, it is an enzyme found mainly in the liver and kidneys. As already mentioned, it is also referred to as GOT, GOT, aspartate aminotransferase, p-AST or s-AST.
L'AST it is a little less specific for detecting liver damage than ALT, as the aspartate aminotransferase AST is found in many organs besides the liver (heart, kidneys ..) and its rise is not necessarily a sign of liver damage. Alanine amyotransferase ALT, on the other hand, is found mainly in the liver and has a longer residence time in the blood.
In some liver diseases, AST is higher than ALT, for example in liver injury from alcohol abuse, in cirrhosis and hepatocellular carcinoma. In particular, an AST to ALT ratio greater than 2 is indicative of alcohol harm, and an AST / ALT ratio greater than 3 is highly suggestive of acute alcohol damage.
What does AST do? AST as already mentioned is an enzyme, which catalyzes (catalyzing means increasing the speed and effectiveness of the reaction) the conversion of aspartate and α-ketoglutarate to glutamate, according to the following formula
Aspartate (Asp) + α-ketoglutarate ⇌ oxaloacetate + glutamate (Glu)
The synthesis of AST, and in general the synthesis of transaminases, depends on vitamin B6 (pyridoxine) and is therefore decreased in all those situations in which there is a low vitamin B6, such as in malnutrition, severe renal insufficiency and advanced liver cirrhosis .
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Normal values of AST or GOT
Normal reference levels for AST aspartate transaminase are:
- AST normal values in men: 6-34 IU / L (International Units per Liter)
- AST normal values in women: 8-40 IU / L (International Units per Liter)
Causes of high AST or GOT - high alanine aminotransferase
There are a number of conditions associated with the finding of got transaminases and high gpt, especially high levels of AST. Here are the most common causes of an increase in AST and ALT.
Very high transaminase levels
- Acute liver damage: L'acute hepatitis it is an acute inflammation of the liver, which can lead to a simple increase in tranasminase (GPT / GOT or ALT / AST) and cholestasis indices (GGT / ALP), but also to an impairment of the protein synthesis function of the liver, up to terminal liver failure. The main forms of acute hepatitis are acute viral hepatitis (mostly hepatitis HAV, HEV and HBV, much rarer HCV hepatitis), l'acute alcoholic hepatitis, hepatitis from substances such asdrug-induced hepatitis (eg paracetamol) olfungal hepatitis (for example amanita phalloides.) and theautoimmune hepatitis in the acute phase. Transaminase levels are not necessarily correlated with prognosis, i.e., paradoxically, patients with a significant increase in AST and ALT could have complete resolution of the problem without sequelae, while people with minimal transaminase alterations could already hide advanced liver disease. Note: In acute hepatitis, AST levels usually remain elevated for about 1-2 months, and it may take up to 3-6 months to return to normal.
- Tumor necrosis: for example in the presence of a primary tumor of the liver (hepatocarcinoma or HCC) or secondary mtastases of other neoplasms (especially prostate and colon).
Moderately elevated transaminase levels
The conditions associated with moderate levels instead elevated AST They are the following:
- Chronic liver disease (chronic viral hepatitis such as chronic hepatitis HCV, chronic hepatitis HBV with or without HDV co-infection, chronic alcoholic liver disease, hemochromatosis, autoimmune liver disease). In chronic hepatitis, AST levels usually do not exceed 3 or 4 times the normal threshold.
- Alcohol abuse with an intake of more than 3 alcoholic units per day (one alcoholic unit corresponds more or less to a glass of wine, a small beer or a glass of spirits)
- Cholestasis (for example when a stone occludes the biliary tract, causing a major increase in GGT, ALP and bilirubinemia, but often only a modest increase in GOT and GPT). Also going on pancreatitis there may be coexisting cholestasis and
- Cardiac damage (myocadic infarction, heart failure such as in an episode of heart failure): in acute heart infarction, transaminases are released for damage to the heart muscle, but also for the possible ischemic damage secondary to the hypo-inflow of blood in the liver. In heart failure, on the other hand, the major cause of transaminase release is hepatic suffering linked to congestion of venous blood which is not pumped sufficiently and stagnates upstream of the right ventricle (liver from stasis)
- Acute kidney damage: in acute renal failure (AKI, Acute Kidney Injury) there may be an increase in liver enzymes, partly due to release from the renal parenchyma, partly due to the reduced elimination of those already present in the blood.
- Muscle damage or injuries: in the event of intense physical exertion or muscle trauma, there may be an increase in ALT and AST transaminases.
- Hemolysis: when, for various reasons, so many circulating red blood cells are destroyed in a short time, there may be an increase in bilirubin and, less frequently, also in transaminases and cholestasis indices,
- Heat stroke: in heatstroke, if very intense, there may be tissue damage with release of alanine aminotransferase and apsartate transaminase (ALT and AST).
- High consumption of vitamin A
- Leptospirosis: Leptospirosis is an infectious disease caused by bacteria of the Leptospira genus and is called field fever, ditch fever or seven-day fever. It contracts when it comes into contact with water contaminated with feces or urine from rodents or other infected animals. Typical mode of infection is bathing in stagnant water. In the acute phase it simulates a viral hepatitis and causes an increase in transaminases.
- Mononucleosis: secondary infection to the Epstein Barr virus (EBV), can also temporarily affect the liver and spleen, enlarging their volume and causing an increase in transaminases.
- CMV Cytomegalovirus Infection: As with mononucleosis, CMV can also affect the liver and cause high GPT and GOT.
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Mildly elevated transaminase levels
Conditions associated with just high levels of ALT They are the following:
- Fatty liver: also called fatty liver, reflects an increase in intrahepatic lipids.
- Moderate use of alcohol without exceeding 3 alcoholic units per day.
- Low-activity cirrhosis of the liver.
- Pregnancy: ASTs in pregnancy usually remain normal or decrease a little. Nonetheless, the finding of high transaminases in pregnancies it is frequent, and often benign, linked to weight gain with consequent fatty liver disease during gestation. In any case, in the event of high AST and ALT transaminases during pregnancy, the treating physician or gynecologist must always be notified and promptly investigated to identify the cause.
- Celiac disease: celiac disease is often diagnosed following investigations carried out for the finding of high transaminases. Although the organ damage in celiac disease is not hepatic but intestinal, it is not uncommon to have moderate increases in ALT and ALT during celiac disease.
Drugs and high AST - high GOT - high aspartate aminotransferase
THE medications how can they cause an increase in ALT and AST?
Hepatocellular damage caused by drugs can be transient and / or minor, but also very serious, and of a definitive nature.
Here is a list of very common medications that can cause ALT and AST to rise:
- Paracetamol: paracetamol is the active ingredient of the very famous Tachipirina. Paracetamol hepatotoxicity is due to the toxic metabolite NAPQI, generated by cytochrome P-450-2E1. Alcohol and other drugs induce cytochrome P-450-2E1 and may contribute to increasing the severity of the toxic insult. In adults, a dose of paracetamol greater than 8 g is capable of producing hepatic necrosis. However, even doses of 4-8g per day can produce liver damage in people with alcohol problems or in individuals with liver disease.
- Amoxicillin: Amoxicillin is one of the best known and most used antibiotics in the world. Amoxicillin causes a moderate increase in AST and ALT levels. Ongoing therapy with amoxicillin (whose most famous trade name is the Augmentin) various types of hepatic dysfunction have been reported, with jaundice, hepatic cholestasis and acute hepatitis.
- Amiodarone: Amiodarone can cause impaired liver function up to 50 % of cases. The type of liver damage caused by amiodarone ranges from an isolated alteration of GPT and GOT (i.e. the transaminases AST and ALT) without real permanent liver damage, to fulminant hepatitis, which fortunately is very rare. Hepatotoxicity (liver damage) usually develops one year after starting amiodarone therapy, although high transaminases are not uncommon even after a few weeks of therapy. Usually the damage mediated by amiodarone (most famous trade name is Cordarone) is dose-dependent, i.e. increases with increasing overall amiodarone dose taken during treatment, and has a direct hepatotoxic effect.
- Chlorpromazine: chlorpromazine is a phenothiazine neuroleptic, and is a drug that finds its place in the therapy of schizophrenia (best known trade name is Largactil). Hepatic damage from chlorpromazine is characterized by an increase in cholestasis indices (GGT and ALP, or gammaglutamyl transpeptidase and alkaline phosphatase) with possible cutaneous jaundice, much greater than the increase in transaminases, which may also be normal. Most cases occur 2-4 weeks after starting therapy.
- Ciprofloxacin: ciprofloxacin is an antibiotic belonging to the quinolone class, and is known under the trade name of Ciproxin. These antibiotics can cause cholestatic damage with an increase in cholestasis and bilirubin indices, and consequent jaundice. About 2% of patients taking ciprofloxacin have elevated ALT or AST levels during therapy, which normalize upon termination of therapy.
- Diclofenac: diclofenac is the active ingredient of the well-known Voltaren. It can cause elevation of ALT and AST transaminases, especially in older women who appear to be more prone to anti-inflammatory liver damage (NSAIDs). High transaminases are found in approximately 15% of patients treated with diclofenac. Significant elevations in ALT or AST (i.e., more than 3 times the upper limit of normal) affect approximately 2% of patients during the first 2 months of treatment.
- Erythromycin: erythromycin is an antibiotic, still widely used in children, a little less in adults it can cause liver dysfunction, including an increase in liver enzymatic levels of AST (GOT) and ALT (GPT), as well as cholestatic hepatitis with an increase in GGT, ALP and total and fractionated bilirubin. A cholestatic reaction (i.e. with stagnation of bile, manifested by an increase mainly in bilirubin, GGT and ALP) is the most common adverse effect, usually starting within 2-3 weeks of starting therapy.
- Fluconazole: fluconazole, known by the commercial name of Diflucan, is an antifungal drug, commonly used for example to fight urinary or genital candida. The spectrum of liver function abnormalities ranges from minimal changes, such as a slight transient increase in transaminase levels to the onset of hepatitis, cholestasis, and fulminant liver failure.
- Isoniazid Isoniazid is an anti-tuberculosis drug: during therapy with isoniazid it is not uncommon to find alterations in liver function, up to severe fulminant hepatitis, potentially fatal. The risk of developing hepatitis is age-related, with an incidence of 8 cases per 1000 in people over the age of 65. Furthermore, the risk of hepatitis increases if there is significant daily alcohol consumption. Mild impairment of liver function or a transient rise in serum transaminase levels occurs in 10-20% of patients taking Isoniazid. In most cases, the enzyme levels return to the reference range without there being a need to stop the drug. Occasionally, however, damage occurs that progresses more and more. For this, people who are taking Isoniazid need to be closely monitored with blood tests at monthly intervals. Especially for people over the age of 35, liver enzymes should be measured before starting therapy, and then periodically during treatment.
- Methyldopa: methyldopa is an antihypertensive drug, contraindicated for people with liver disease. Currently it is a little out of use, it is often used in pregnant women. During methyldopa therapy, periodic monitoring of liver function should be done during the first 6-12 weeks of treatment.
- Oral contraceptives: oral contraceptives can cause intrahepatic cholestasis with itching and jaundice. Patients with a history of idiopathic jaundice in pregnancy, or who had severe pregnancy pruritus, or a positive family history for these disorders are more susceptible to liver damage.
- Statins: statins, more correctly called HMG-CoA reductase inhibitors, are drugs used to control fats in the blood and in particular the cholesterol. The most commonly used statins are simvastatin is atorvastatin. The use of statins is often associated with abnormal liver function, as well as a frequent increase in creatinine kinase (CPK), an indicator of muscle damage. A moderate alteration in serum transaminase levels (less than 3 times the upper limit of the reference range) is often found after the start of therapy, and is in any case often transient. The finding of moderately elevated AST and ALT transaminases is not accompanied by any symptoms and usually does not require discontinuation of treatment. A persistent increase in serum transaminase levels (more than 3 times the upper limit of the reference range) occurs in approximately 1% of patients.
- Rifampicin: Rifampicin is an antibiotic as well as an antituberculosis, and is generally administered together with Isoniazid. Rifampicin can also cause liver damage, usually mild, with elevation of ALT and AST. In patients taking rifampicin with other hepatotoxic agents, episodes of jaundice, liver failure and in some cases even death have occurred. For this reason, careful monitoring of the hepatic function of GPT and GOT (ALT and AST) is appropriate in patients receiving rifampicin.
- Valproic acid and sodium valproate: Valproic acid generally causes hepatic steatosis, and it is not uncommon to notice an elevation in AST and ALT transaminases during treatment. This drug should not be given to patients with active liver disease.
- Herbal products: very dangerous as they are often underestimated and are not considered potentially harmful. In reality they may contain hepatotoxic substances, and not being considered drugs, these are often not reported on the label, or if they are reported, however, the dosages are not known.
High AST - High GOT Symptoms - High Aspartate Aminotransferase Symptoms
What are the symptoms of a high aspartate aminotransferase? Symptoms of high AST are those that suggest liver disease, or another organ that may release transaminases, such as:
- Asthenia (weakness and easy fatigue)
- Loss of appetite (hyporxia or anorrxia)
- Nausea and / or vomiting, typically characterizes acute hepatitis, but also viral infections such as mononucleosis and CMV.
- Abdominal swelling, which could be bloating or the initial accumulation of fluid in the abdomen (ascites)
- Abdominal pain, freuqnete in patients with cirrhosis and ascites due to the high incidence of urinary and peritoneal infections
- Yellow discoloration of the eyes and skin (scleral and skin jaundice)
- Dark urine (cola color)
- Light-colored stools (greyish, like clay)
- Very dark stools (blackish, coffee grounds type)
- Itching (due to the increase in bile salts in the circulation)
- Behavior changes, confusion, daytime sleepiness and sleeplessness at night
- Chest pain, shortness of breath, need to sleep with two or three pillows, swelling in the legs and jugular veins in case of heart problems
- Reduction of diuresis (little pee during the day)
- Skin hematomas in case of a recent muscle trauma.
When to take the exam
When is it worth doing blood tests for AST and ALT?
The transaminases GOT and GPT (ALT and AST) must be measured:
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- when one suspects liver disease (i.e. in the presence of: jaundice, fatigue (asthenia), nausea, vomiting, light or very dark stools, dark urine, itching, ascites (water in the abdomen), mental changes, history of alcohol abuse, suspected paracetamol overdose, family history of liver disease, exposure to hepatitis viruses)
- for monitor liver function if it is known that there are liver problems (ie in case of use of potentially hepatotoxic drugs, presence of fatty liver disease, chronic liver disease, cirrhosis, liver failure, Wilson's disease, hemochromatosis).
What do you need and how do you make the withdrawal?
AST will be dosed using a small amount of blood usually drawn from the crook of the arm. You don't need to be fasting to take the exam.Tags: Laboratory medicine Blood