What is the normal range for ALT blood test? Discover high, low & normal results, plus symptoms and causes of abnormal ALT levels.

Understanding ALT Blood Test: Purpose, Procedure, and Results

An alanine aminotransferase (ALT) test measures the level of the enzyme ALT in your blood. This test can help doctors evaluate liver function or determine the underlying cause of a liver problem. ALT is an enzyme that is found mostly in the liver, and it plays a crucial role in metabolism, turning food into energy.

The ALT test is often part of an initial screening for liver disease. When your liver is damaged or inflamed, ALT can be released into your bloodstream, causing serum ALT levels to rise. An increase in ALT is often the first sign of a liver problem, and ALT is often elevated before other symptoms appear.

An ALT test is also known as a serum glutamic-pyruvic transaminase (SGPT) test or an alanine transaminase test. It is usually used to determine whether someone has liver injury or failure. Your doctor may order an ALT test if you’re having symptoms of liver disease, such as jaundice, dark urine, nausea, vomiting, or pain in the right upper quadrant of your abdomen.

Normal ALT Levels: What is the Acceptable Range?

According to the American College of Gastroenterology, the normal value for ALT in blood for people without risk factors for liver disease ranges from 29 to 33 international units per liter (IU/L) for males and 19 to 25 IU/L for females. This value can vary depending on the lab, and it’s important to discuss your specific results with your doctor.

Abnormal ALT Levels: Causes of High and Low Results

Higher-than-normal levels of ALT can indicate liver damage. Increased levels of ALT may be a result of conditions such as hepatitis, cirrhosis, fatty liver disease, and alcohol abuse. Factors that can contribute to high ALT levels include:

• Viral hepatitis (hepatitis A, B, or C)
• Cirrhosis (scarring of the liver)
• Fatty liver disease (non-alcoholic and alcoholic)
• Excessive alcohol consumption
• Certain medications (e.g., statins, acetaminophen, antibiotics)
• Liver cancer or other liver diseases
• Muscle injury or damage

Low ALT levels, on the other hand, are less common and may be associated with conditions such as malnutrition, severe liver disease, and certain genetic disorders. However, low ALT levels do not necessarily indicate a problem, and they may simply be a normal variation for some individuals.

Symptoms of Abnormal ALT Levels

What are the symptoms associated with high or low ALT levels? Elevated ALT levels are often accompanied by symptoms of liver damage or dysfunction, such as:

• Jaundice (yellowing of the skin and eyes)
• Dark-colored urine
• Nausea and vomiting
• Abdominal pain or discomfort
• Fatigue and weakness
• Loss of appetite

Low ALT levels, on the other hand, are often asymptomatic and may not cause any noticeable symptoms. In some cases, low ALT levels may be associated with conditions such as severe liver disease, malnutrition, or certain genetic disorders.

Preparing for an ALT Blood Test

An ALT test doesn’t require any special preparation. However, you should tell your doctor about any prescription or over-the-counter medications you’re taking, as some medications may affect the levels of ALT in your blood. Your doctor might tell you to avoid taking certain medications for a period of time before the test.

The test itself involves taking a small sample of blood. A healthcare professional will use an antiseptic to clean the area where the blood will be drawn, tie an elastic band around your upper arm to make the veins more visible, insert a needle to draw the blood, and then apply pressure to the puncture site to minimize the risk of bruising.

Interpreting ALT Test Results

Your doctor will receive the test results from the laboratory and may schedule an appointment with you to explain the results in more detail. It’s important to discuss your specific results with your doctor, as the normal range can be affected by factors such as sex and age.

If your ALT levels are abnormal, your doctor may order additional tests or refer you to a specialist to further investigate the underlying cause and develop an appropriate treatment plan.

When to Seek Medical Attention

If you are experiencing symptoms of liver disease or have risk factors for liver problems, it is important to discuss your concerns with your healthcare provider. They can order an ALT test and other relevant tests to evaluate your liver function and determine the appropriate course of action.

Don’t hesitate to seek medical attention if you have any concerns about your liver health or if you notice any changes in your symptoms or overall well-being. Early detection and proper management of liver problems can greatly improve your health outcomes.

ALT (Alanine Aminotransferase) Test: Purpose, Procedure, and Results

An alanine aminotransferase (ALT) test measures the level of the enzyme ALT in your blood. This test can help doctors evaluate liver function or determine the underlying cause of a liver problem.

ALT is an enzyme that is found mostly in the liver. The liver is the body’s largest gland. It has several important functions, including:

• making proteins
• storing vitamins and iron
• removing toxins from your blood
• producing bile, which aids in digestion

Proteins called enzymes help the liver break down other proteins so your body can absorb them more easily. ALT is one of these enzymes. It plays a crucial role in metabolism, turning food into energy. The ALT test is often part of an initial screening for liver disease.

ALT is normally found inside liver cells. However, when your liver is damaged or inflamed, ALT can be released into your bloodstream. This causes serum ALT levels to rise.

An increase in ALT is often the first sign of a liver problem, and ALT is often elevated before other symptoms appear.

An ALT test is also known as a serum glutamic-pyruvic transaminase (SGPT) test or an alanine transaminase test.

The ALT test is usually used to determine whether someone has liver injury or failure. Your doctor may order an ALT test if you’re having symptoms of liver disease, including:

• jaundice, which is yellowing of your eyes or skin
• dark urine
• nausea
• vomiting
• pain in the right upper quadrant of your abdomen

Liver damage generally causes an increase in ALT levels. The ALT test can evaluate the levels of ALT in your bloodstream, but it can’t show how much liver damage there is or how much fibrosis, or scarring, is present.

The test also can’t predict how severe the liver damage will become.

An ALT test is often done with other liver enzyme tests. Checking ALT levels along with levels of other liver enzymes can provide your doctor with more specific information about a liver problem.

An ALT test may be part of a routine checkup or requested if someone has risk factors for liver disease, including:

• family history
• heavy alcohol use
• exposure to hepatitis
• taking certain medications
• diabetes

Other reasons to perform an ALT test include:

• monitoring the progression of liver diseases, such as hepatitis or liver failure
• assessing whether treatment for liver disease should be started
• evaluating how well treatment is working

An ALT test doesn’t require any special preparation. However, you should tell your doctor about any prescription or over-the-counter medications you’re taking. Some medications may affect the levels of ALT in your blood.

Your doctor might tell you to avoid taking certain medications for a period of time before the test.

An ALT test involves taking a small sample of blood, as outlined here:

1. A healthcare professional uses an antiseptic to clean your skin in the area where they will take the sample.
2. They will tie an elastic band around your upper arm, which stops the flow of blood and makes the veins in your arm more visible.
3. Once they find a vein, they will insert a needle. This may cause a brief pinching or stinging sensation. The blood is drawn into a tube attached to the end of the needle. In some cases, more than one tube may be required.
4. After enough blood has been collected, the healthcare professional removes the elastic band and the needle. They place a piece of cotton or gauze over the puncture site and cover that with a bandage or tape to keep it in place.
5. The blood sample is sent to a laboratory for analysis.
6. The laboratory sends the test results to your doctor. Your doctor may schedule an appointment with you to explain the results in more detail.

An ALT is a simple blood test with few risks. Bruising can sometimes occur in the area where the needle was inserted. The risk of bruising can be minimized by applying pressure to the injection site for several minutes after the needle is removed.

In very rare cases, the following complications can occur during or after an ALT test:

• excessive bleeding where the needle was inserted
• an accumulation of blood beneath your skin, which is called a hematoma
• lightheadedness or fainting at the sight of blood
• an infection at the puncture site

Normal results

According to the American College of Gastroenterology, the normal value for ALT in blood for people without risk factors for liver disease ranges from 29 to 33 international units per liter (IU/L) for males and 19 to 25 IU/L for females. This value can vary depending on the lab.

This range can be affected by certain factors, including sex and age. It’s important to discuss your specific results with your doctor.

Abnormal results

Higher-than-normal levels of ALT can indicate liver damage. Increased levels of ALT may be a result of:

• hepatitis, which is an inflammatory condition of the liver
• cirrhosis, which is severe scarring of the liver
• death of liver tissue
• a tumor or cancer in the liver
• a lack of blood flow to the liver
• hemochromatosis, which is a disorder that causes iron to build up in the body
• mononucleosis, which is an infection usually caused by the Epstein-Barr virus
• diabetes

Most lower ALT results indicate a healthy liver. However, studies have shown that lower-than-normal results have been related to increased long-term mortality. Discuss your numbers specifically with your doctor if you’re concerned about a low reading.

If your test results indicate liver damage or disease, you may need more testing to determine the underlying cause of the problem and the best way to treat it.

What Does It Mean When Your ALT Is High? > Personalabs

Getting elevated alanine aminotransferase (ALT) or serum glutamic-pyruvic transaminase (SGPT) in your liver function test can be distressing. But what high ALT means depends on factors such as the medications you’re taking, underlying liver disorders, chronic drinking, and consumption of herbal medicine. 

Understanding the roles of ALT and its sudden spike in the bloodstream will provide clues on your liver health. Read more about it in the next few lines. 

What Is an ALT Lab Test? 

An ALT blood test measures the alanine aminotransferase (ALT) enzyme level to detect liver damage caused by diseases like hepatitis or lifestyle factors such as habitual drinking. The enzyme is an ideal marker for health conditions concerning the liver as it is released to the bloodstream when the liver sustains injuries or undergoes dysfunction. 

However, ALT bloodwork does not produce conclusive results on its own. Therefore, it is usually taken as part of the hepatic function panel test and comprehensive metabolic panel, along with other blood tests for other liver enzymes. 

In some cases, you might take the ALT blood test first, followed by other labwork to confirm a suspected condition or the other way around. These tests include:

• AST (aspartate aminotransferase) test
• GGT (gamma-glutamyl transferase) test
• ALP (alkaline phosphatase) test
• ALB (albumin) test
• Total bilirubin blood test

ALT Blood Test: Preparation and Results Meaning 

Measuring ALT levels is done through blood work, wherein you will have to visit a laboratory for a phlebotomist to collect your blood sample. 

Although there is no special preparation before the blood collection for an ALT blood test, you may need to fast if you take it alongside other tests. For example, if it is part of a liver function panel where a bilirubin lab test is involved, you will need to abstain from food and drinks for about 8 hours before the test. 

What Does It Mean When Your ALT Is High?

Your ALT level is considered high if it exceeds the normal range of 0 to 44 IU/L. Some laboratories may present a slightly different reference interval, but a test result of 55 IU/L or above could indicate liver problems. If the value exceeds the upper limit of the normal range, it could suggest liver disease or cirrhosis (tissue scarring).  

However, other factors could contribute to the increase of ALT in your blood – not just liver disorders. Here are common causes of high ALT:

Infections

Patients diagnosed with hepatitis, whether A, B, or C, typically have elevated ALT liver enzymes. Hence, if you got a test value exceeding the normal range of ALT and are showing hepatitis symptoms, consult your doctor to secure the proper diagnostic lab tests.

Aside from hepatitis, studies have also shown that those with infectious mononucleosis have elevated liver enzymes, including ALT. So your doctor may proceed to check for swelling in your tonsils and liver on top of common infection symptoms. 

Did you know? Hepatitis can be prevalent among older kids. That’s why it’s vital to detect hepatitis in children at the onset of the symptoms. This allows for better treatment and speedy recovery.  

Medications

Various drugs can cause high ALT levels, such as anti-seizure medications (phenytoin, valproic acid, carbamazepine, etc.), antidepressants, antipsychotics, cholesterol-lowering drugs, heparin therapy, acetaminophen, and many others. So if you’re taking these medications, make sure to let your doctor know. 

Herbal Supplement

Herbal teas and supplements can also elevate your ALT. These include kava, chaparral, ephedra, skull cap, comfrey tea, and Yohimbe. While traditional medicine may suggest that these supplements benefit your health, consult with your healthcare provider before taking them regularly.   

Alcohol and Toxins

Alcohol has been known to cause fatty liver tissues and induce inflammation. As a result, binge drinking elevates liver enzymes like ALT and causes gradual hepatic damage. Other substances like cocaine and poisonous liquid also increase ALT, as they generate high levels of hepatic toxicity.  

Diseases

Medical conditions associated with high ALT include hemochromatosis (iron overload), fatty liver disease, cirrhosis, thyroid disease, diabetes, Celiac disease, cancer, hemolysis, etc. Heart disease has also been associated with elevated ALT. 

If you have a family history of liver disease, there’s a higher chance of getting elevated ALT in your bloodwork, especially with an unhealthy lifestyle. So opt for a CMP 14 blood test to be included in your annual wellness checkup to detect liver problems early. 

What Should I Do if My ALT Is High? 

Seeing an elevated ALT in your test results can be alarming, especially if it’s far off the upper limit and if the other parameters also go beyond the normal range. But you can lower this liver enzyme (along with the others) through the following ways:

1. Get Tested for the Cause of Increased ALT

Finding the root cause of your elevated ALT, whether it’s a disorder or a medication, is imperative for the right course of action in normalizing it. In addition, be mindful of symptoms you may have been experiencing, especially those related to liver problems. These could include abdominal pain and swelling, appetite loss, fatigue, dark urine, pale stool, vomiting, itchy and easily bruised skin, and jaundice (yellow eyes and skin). 

Your doctor will assess your symptoms and request appropriate liver function tests. Once the condition is diagnosed, you will be given proper treatment. You will most likely take another ALT test, among others, to see if you already have low ALT levels within the normal range. 

2. Limit Cholesterol and Avoid High-Carb Foods

Changing your diet typically tops the lifestyle changes that improve your liver health. In the case of high ALT, shifting to a low carbohydrate diet has a beneficial impact on normalizing the liver enzyme’s production. 

In a 2015 study, high carbohydrate intake of fructose-rich food and beverages significantly increased ALT. On the other hand, a low-carb diet decreases the enzyme twice as a low-fat diet. 

While carbohydrates seem to trigger the spike in liver enzymes, fat, specifically bad cholesterol, doesn’t do any favor. High cholesterol overloads liver function, increases ALT, and even promotes the risk of liver cancer. That said, it’s best to avoid fatty foods such as whole-milk dairy, red meat, and those smothered in oil. 

Think you have high cholesterol? You will know for certain when you take the comprehensive lipid profile blood test. Doing so allows you to have a base record of your lipid levels, helping you assess your risk for heart and liver disease. 

3. Drink a Cup of Coffee a Day

Coffee comes with plenty of health benefits. However, it can be subjective depending on your physical and mental state. But in the case of liver function, studies have shown that drinking coffee aids in preventing high serum ALT.

Moreover, a 2015 study says that drinking coffee reduces your risk for liver cancer and chronic liver disease, bordering cirrhosis. So secure one cup of coffee daily, especially in lieu of alcohol. If you have anxiety disorders, consult your doctor first, as too much coffee can aggravate the condition. 

4. Be More Physically Active

Exercise promotes liver health and allows you to lose weight. By being physically active for about 30 minutes daily, you improve your metabolism, which involves the oxidation of fatty acids. This helps ease liver function and, by extension, prevents injuries that lead to increased liver enzymes in the blood. 

Consistent physical activity is particularly helpful for those with fatty liver. In a 2018 review, evidence shows that regular exercise aid liver functions in people with nonalcoholic fatty liver disease (NAFLD), from damage reduction to improved insulin resistance.  

5. Avoid Alcohol and Smoking

It’s no secret that alcohol can cause severe liver damage if consumed habitually. Heavy drinkers are prone to alcoholic liver disease and alcoholic hepatitis. On top of that, alcohol is also the most significant risk factor for liver cirrhosis. 

Smoking is another habit you should shake off if you plan to lower your serum ALT. According to an article published in the Journal of Hepatology, cigarette smoking aggravates liver problems and contributes to the impediment of hepatic treatment. This remains true with secondhand smoke. 

If you’re having trouble leaving these unhealthy habits behind, seek help from professionals and support from your social circle. 

6. Rethink Taking Supplements, Drugs, or Herbal Medicines

As herbal teas and vitamin supplements (iron and vitamin A) can cause liver toxicity, make sure to avoid them if you have elevated liver enzymes. Likewise, consult your doctor regarding taking prescribed medications and be sure not to take them beyond the recommended dosage. For example, acetaminophen (a drug for fever and pain) can induce acute liver damage if taken in large amounts. 

Other Frequently Asked Questions 

Which is worse: high AST or ALT?

Liver enzymes AST and ALT are often compared to better understand liver health. Getting high lab values for both AST and ALT indicates the severity of the liver problem. Generally, if AST is significantly elevated than an already high ALT, it could suggest cirrhosis, which can lead to liver failure. 

How quickly can ALT levels drop?

On average, ALT decreases significantly after treatment and lifestyle changes in about four weeks. This depends on how consistent you are with the necessary adjustments. For example, if you have given up alcohol, your ALT could start to drop in a week and continue to do so with continuous abstinence. 

Can ALT levels go down on their own?

Unless you change your diet, start exercising, and eliminate unhealthy habits like heavy drinking and smoking, serum ALT levels will not decrease. Additionally, if the elevation of the liver enzyme is due to a severe liver disorder, failing to address and avail of proper treatment will only contribute to high ALT remaining unchanged. 

Bottom Line 

When your ALT levels are elevated, it’s certainly high time to check your liver. Doing so allows you to seek proper treatment and employ the necessary lifestyle adjustments, such as changing your diet, getting tested for a particular disorder, and being physically active. If symptoms of liver damage are observed, consult your doctor immediately. 

ALT (blood test ALT, Alanine aminotransferase, alanine transaminase, SGPT, Alanine aminotransferase).

Test material
Blood serum

Method of determination
Kinetic UV test (optimized, standardized by DGKC).

Alanine aminotransferase is an enzyme that is produced inside cells. ALT is most active in the liver, less – in the muscles, heart, pancreas. The enzyme takes an active part in the metabolism of amino acids. Catalyzes the transamination reaction between alanine and α-ketoglutarate. Alanine, in turn, is one of the transport forms of ammonia.

In laboratory diagnostics, an ALT blood test is used to diagnose and evaluate the effectiveness of therapy for diseases of the liver, less often – of the heart and pancreas.

The liver is an important and multifunctional organ. The liver is a “powerful nutrient sorting station”, where synthetic processes take place and useful substances are formed, which are sent through the bloodstream to various organs and tissues. The liver, like a sponge, absorbs everything harmful and destroys toxins, thereby protecting other vital organs from their effects. This is the main “filter” in our body. Poisons, carcinogens, drugs, microbial toxins are destroyed in the liver, and ammonia, poisonous to cells, is converted into urea, which is excreted from the body with urine.

Moreover, the liver is involved in the formation of the immune response, synthesizes glucose when the body lacks it, participates in the formation of bile acids, without which digestion and absorption of fats is impossible. The liver is unique and extremely important, so it needs to be given as much attention as possible.

Main clinical manifestations of liver diseases:

1. Nausea and vomiting.
2. Greyish or yellowish skin tone.
3. Bitter taste in the mouth.
4. Diarrhea.
5. Darkening of the color of urine.
6. Aching pain in the region (right hypochondrium), which may radiate to the back or right shoulder blade.

What does an ALT blood test mean?

The assay consists of determining the activity of the ALT enzyme. Normally, in a healthy person, the level of ALT in the blood serum is very low and corresponds to the reference values: in women – up to 31 U / l, in men – up to 37 U / l.

When cells containing this enzyme are damaged or destroyed, it enters the bloodstream, and its concentration in it increases. In viral hepatitis, an increase in enzyme activity occurs even before the onset of jaundice and even in patients with anicteric form of the disease. With a favorable course of the disease, ALT activity slowly returns to normal. An increase in the activity of this enzyme is observed in toxic and alcoholic hepatitis, myocardial infarction, shock and burns, muscle diseases and severe pancreatitis. An increase in ALT levels is also noted in women in the first trimester of pregnancy and physiological bone growth, less often in elderly patients over 50 years of age.

Even a slight increase in ALT activity should be a reason for re-examination and contacting a doctor.

An important diagnostic indicator is also the ratio of the activity of alanine aminotransferase (ALT) and an enzyme from the same group – aspartate aminotransferza (AST) called “de Ritis coefficient”. Normally, it is 0.8-1. In acute viral and toxic hepatitis, the indicator decreases to 0.2-0.5, and in myocardial infarction it rises above one.

ALT blood chemistry when administered to children

ALT – alanine aminotransferase – an enzyme that plays a key role in amino acid metabolism. ALT is found in the liver, as well as in skeletal muscle and the heart. In smaller quantities, it is found in the pancreas, spleen, and lungs.

Usually the concentration of ALT in the blood is insignificant, but when the cells of the corresponding organs are destroyed, the transferase enters the bloodstream, and its level rises. Therefore, in clinical practice, the determination of the level of ALT in the blood serum is used to diagnose diseases of the liver and some other organs.

When is an ALT blood test ordered?

As a rule, a simultaneous analysis of ALT and AST (alanine aminotransferase and aspartate aminotransferase) is prescribed. Usually this analysis is needed to diagnose diseases of the heart, liver, abdominal or chest injuries, to monitor liver function during serious treatment (for example, antiretroviral therapy for HIV). A blood test for ALT and AST is indicated for intoxication, autoimmune and endocrine pathologies, and allergies. An analysis of ALT and AST is included in a comprehensive biochemical blood test during pregnancy.

IMPORTANT! Information from the article cannot be used for self-diagnosis and self-treatment! Only a doctor can prescribe the necessary examinations, establish a diagnosis and draw up a treatment plan for a consultation!

How to prepare for the analysis?

A week before the analysis, do not abuse salty, fatty, spicy, flour and sweet. Blood for ALT and AST should be taken on an empty stomach, you should also not smoke before the analysis. Before analysis for ALT and AST, X-rays and ultrasound are not prescribed.

If ALT is elevated

ALT levels vary by age. The norm of ALT in men and women is different.

• An increase in ALT up to 3 times is considered small.
• Moderately elevated ALT is considered to be 3-19 times higher than normal.
• If ALT is increased by more than 20 times, such an increase is considered significant.