What is the normal range for ALT in a blood test. How is the ALT blood test performed. Why do doctors order ALT tests. What do abnormal ALT results indicate. How to prepare for an ALT blood test. What are the potential risks of an ALT test. How does ALT relate to liver function.

Understanding the Alanine Transaminase (ALT) Blood Test

The Alanine Transaminase (ALT) blood test is a crucial diagnostic tool used to assess liver health and function. ALT, also known as Serum Glutamate Pyruvate Transaminase (SGPT) or Alanine Aminotransferase, is an enzyme primarily found in liver cells. When liver cells are damaged or die, ALT is released into the bloodstream, making it an excellent indicator of liver health.

What is ALT and its role in the body?

ALT is an enzyme that plays a vital role in metabolism. It catalyzes the transfer of amino groups between alanine and glutamate, which is essential for the production of proteins and other important molecules. While ALT is found in various tissues throughout the body, it is most concentrated in the liver, making it a sensitive marker for liver damage.

The Normal Range for ALT in Blood Tests

Understanding the normal range for ALT levels is crucial for interpreting test results. The normal range for ALT can vary slightly depending on the laboratory and the specific testing method used. However, generally accepted ranges are as follows:

• For adults: 4 to 36 units per liter (U/L)
• For children: The range can be wider and may vary with age

It’s important to note that “normal” can differ based on factors such as age, sex, and overall health. Always consult with your healthcare provider to interpret your specific results.

Factors affecting ALT levels

Several factors can influence ALT levels in the blood, including:

• Age and gender
• Body mass index (BMI)
• Certain medications
• Alcohol consumption
• Exercise intensity and frequency
• Underlying health conditions

The ALT Blood Test Procedure

The ALT blood test is a straightforward procedure that involves drawing a small sample of blood from a vein, typically in the arm. Here’s what you can expect during the test:

1. A healthcare professional will clean the area with an antiseptic.
2. An elastic band may be placed around your upper arm to make the vein more visible.
3. A needle will be inserted into the vein to collect the blood sample.
4. The blood is collected in a tube for analysis.
5. The needle is removed, and pressure is applied to stop any bleeding.
6. A bandage is placed over the puncture site.

The entire process usually takes less than five minutes. While some people may experience slight discomfort or a brief pinching sensation during the blood draw, serious complications are rare.

Preparing for an ALT blood test

In most cases, no special preparation is required for an ALT blood test. However, your healthcare provider may give you specific instructions based on your individual circumstances. These may include:

• Fasting for a certain period before the test
• Avoiding certain medications or supplements
• Refraining from strenuous exercise before the test

Always follow your doctor’s instructions to ensure the most accurate results.

Reasons for Ordering an ALT Blood Test

Healthcare providers may order an ALT blood test for various reasons, including:

• Screening for liver disease
• Monitoring known liver conditions
• Evaluating the effectiveness of liver treatments
• Assessing potential liver damage from medications
• Investigating unexplained symptoms that may be related to liver function

An ALT test is often performed as part of a comprehensive metabolic panel or liver function tests, which provide a broader picture of overall health and organ function.

When is an ALT test most commonly ordered?

An ALT test may be ordered in the following situations:

• As part of routine health screenings
• When a patient shows symptoms of liver disease
• To monitor patients with known liver conditions
• Before starting certain medications that may affect liver function
• To evaluate unexplained fatigue, weakness, or jaundice

Interpreting ALT Blood Test Results

Interpreting ALT test results requires considering various factors, including the patient’s overall health, medical history, and other test results. Here’s a general guide to understanding ALT levels:

• Normal ALT levels: Usually between 4 and 36 U/L
• Mildly elevated ALT: Between 37 and 100 U/L
• Moderately elevated ALT: Between 101 and 400 U/L
• Severely elevated ALT: Above 400 U/L

It’s crucial to remember that ALT levels alone do not provide a definitive diagnosis. They are typically interpreted in conjunction with other liver function tests and clinical findings.

What do elevated ALT levels indicate?

Elevated ALT levels can signify various liver issues, including:

• Viral hepatitis (A, B, or C)
• Alcoholic liver disease
• Nonalcoholic fatty liver disease (NAFLD)
• Cirrhosis
• Drug-induced liver injury
• Autoimmune hepatitis
• Hemochromatosis
• Liver cancer

In some cases, elevated ALT levels may be temporary and resolve without intervention. However, persistent elevations warrant further investigation to determine the underlying cause.

Potential Risks and Complications of ALT Blood Tests

While the ALT blood test is generally safe, as with any medical procedure, there are some potential risks and complications to be aware of:

• Slight pain or discomfort at the needle insertion site
• Bruising or swelling at the puncture site
• Dizziness or fainting (rare)
• Excessive bleeding (very rare)
• Infection at the puncture site (extremely rare)

These risks are minimal, and serious complications are uncommon. If you experience persistent pain, swelling, or signs of infection at the puncture site, contact your healthcare provider promptly.

Managing potential side effects

To minimize discomfort and reduce the risk of complications after an ALT blood test:

• Apply pressure to the puncture site for a few minutes after the test
• Keep the bandage on for the recommended time
• Avoid strenuous activities for a few hours after the test
• Stay hydrated to help prevent dizziness

ALT Test in Conjunction with Other Liver Function Tests

While the ALT test is valuable on its own, it is often performed alongside other liver function tests to provide a more comprehensive assessment of liver health. These additional tests may include:

• Aspartate Aminotransferase (AST)
• Alkaline Phosphatase (ALP)
• Gamma-Glutamyl Transferase (GGT)
• Bilirubin
• Albumin
• Prothrombin Time (PT)

The combination of these tests can help healthcare providers differentiate between various liver conditions and assess the severity of liver damage more accurately.

The AST/ALT ratio

One important relationship often examined is the ratio of AST to ALT levels. This ratio can provide additional insights into the nature of liver damage:

• AST/ALT ratio less than 1: Suggests conditions like viral hepatitis or fatty liver disease
• AST/ALT ratio greater than 2: May indicate alcoholic liver disease or advanced liver damage

Lifestyle Factors Affecting ALT Levels

Various lifestyle factors can influence ALT levels, even in individuals without liver disease. Understanding these factors can help interpret test results more accurately and guide preventive measures:

• Alcohol consumption: Regular and excessive alcohol intake can elevate ALT levels
• Obesity: Excess body weight, particularly visceral fat, is associated with higher ALT levels
• Diet: A diet high in processed foods and saturated fats may contribute to elevated ALT
• Physical activity: Regular exercise can help maintain healthy ALT levels
• Medications: Certain drugs, including some over-the-counter pain relievers, can affect ALT levels

Addressing these lifestyle factors can not only help maintain healthy ALT levels but also contribute to overall liver health and general well-being.

Tips for maintaining healthy ALT levels

To support liver health and maintain normal ALT levels, consider the following recommendations:

• Limit alcohol consumption or avoid it altogether
• Maintain a healthy body weight
• Eat a balanced diet rich in fruits, vegetables, and whole grains
• Exercise regularly
• Avoid unnecessary medications and follow dosage instructions carefully
• Get vaccinated against hepatitis A and B
• Practice safe sex and avoid sharing needles to prevent hepatitis C

The Future of Liver Function Testing

As medical science advances, new technologies and approaches are emerging to enhance liver function testing and diagnosis. Some promising developments include:

• Non-invasive imaging techniques: Advanced imaging methods like elastography can assess liver fibrosis without the need for a biopsy
• Genetic testing: Identifying genetic markers associated with liver disease risk
• Biomarker panels: Combining multiple biomarkers for more accurate and comprehensive liver assessment
• Artificial intelligence: Using machine learning algorithms to interpret complex liver function data

These advancements may lead to earlier detection of liver diseases and more personalized treatment approaches in the future.

The role of ALT in personalized medicine

As our understanding of individual variations in liver function grows, ALT testing may play an increasingly important role in personalized medicine. This could involve:

• Tailoring ALT reference ranges based on individual factors like age, sex, and genetic profile
• Using ALT trends over time to predict liver disease risk and guide preventive strategies
• Incorporating ALT levels into comprehensive health algorithms for more accurate disease risk assessment

The future of liver function testing, including ALT assessment, holds the promise of more precise, personalized, and proactive healthcare strategies.

Alanine transaminase (ALT) blood test

Medical Tests 

Definition

The alanine transaminase (ALT) blood test measures the level of the enzyme ALT in the blood.

Alternative Names

SGPT; Serum glutamate pyruvate transaminase; Alanine transaminase; Alanine aminotransferase

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

No special preparation is needed.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

ALT is an enzyme found in a high level in the liver. An enzyme is a protein that causes a specific chemical change in the body.

Injury to the liver results in release of ALT into the blood.

This test is mainly done along with other tests (such as AST, ALP, and bilirubin) to diagnose and monitor liver disease.

Normal Results

The normal range is 4 to 36 U/L.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your health care provider about the meaning of your specific test results.

What Abnormal Results Mean

An increased ALT level is often a sign of liver disease. Liver disease is even more likely when the levels of substances checked by other liver blood tests have also increased.

An increased ALT level may be due to any of the following:

• Scarring of the liver (cirrhosis)
• Death of liver tissue
• Swollen and inflamed liver (hepatitis)
• Too much iron in the body (hemochromatosis)
• Too much fat in the liver (fatty liver)
• Lack of blood flow to the liver (liver ischemia)
• Liver tumor or cancer
• Use of drugs that are toxic to the liver
• Mononucleosis (“mono”)
• Swollen and inflamed pancreas (pancreatitis)

Risks

adam.com”>There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

• Excessive bleeding
• Fainting or feeling lightheaded
• Multiple punctures to locate veins
• Hematoma (blood collecting under the skin)
• Infection (a slight risk any time the skin is broken)

References

Chernecky CC, Berger BJ. Alanine aminotransferase (ALT, alanine transaminase, SGPT) – serum. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:109-110.

Pincus MR, Tierno PM, Gleeson E, Bowne WB, Bluth MH. Evaluation of liver function. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 21.

Pratt DS. Liver chemistry and function tests. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran’s Gastrointestinal and Liver Disease. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 73.

Review Date: 01/26/2019

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. Copyright ©2019 A.D.A.M., Inc., as modified by University of California San Francisco. Any duplication or distribution of the information contained herein is strictly prohibited.

Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Health. Please discuss with your doctor any questions or concerns you may have.

Alanine Aminotransferase (ALT) Test and Results (aka SGPT Test)

Written by WebMD Editorial Contributors

• Why Is ALT Important?
• Why Would My Doctor Order This Test?
• How Do I Prepare?
• What Happens During the Test?
• What Are the Risks?
• What Do the Results Mean?
• What Other Tests Will I Take?
• More

The alanine aminotransferase (ALT) test is a blood test that checks for liver damage. Your doctor can use this test to find out if a disease, drug, or injury has damaged your liver.

Your liver does a lot of important things for you:

• It makes a fluid called bile that helps your body digest food.
• It removes waste products and other toxins from your blood.
• It produces proteins and cholesterol.

Diseases such as hepatitis and cirrhosis can damage your liver and prevent it from doing its many jobs.

This enzyme is found mainly in your liver. Smaller amounts of ALT are in your muscle, kidneys , and other organs.

Your body uses ALT to break down food into energy. Normally, ALT levels in the blood are low. If your liver is damaged, it will release more ALT into your blood and levels will rise. (ALT used to be called serum glutamic-pyruvic transaminase, or SGPT).

Doctors often give the ALT test along with other liver tests.

Your doctor might recommend ALT if you have symptoms of liver disease or damage, such as:

• Stomach pain or swelling
• Nausea
• Vomiting
• Yellow skin or eyes (a condition called jaundice)
• Weakness
• Extreme tiredness (fatigue)
• Dark-colored urine
• Light-colored poop
• Itchy skin

Here are some reasons you might get this test:

• You’ve been exposed to the hepatitis virus.
• You drink a lot of alcohol.
• You have a family history of liver disease.
• You take medicine that’s known to cause liver damage.

The ALT test can be done as part of a blood panel during a regular exam. If you’ve already been diagnosed with liver disease, your doctor can use the ALT test to see how well your treatment is working.

You don’t need any special preparation for the ALT test. Your doctor might ask you to stop eating or drinking a few hours before the test.

Tell your doctor what prescription drugs or supplements you take. Some medicines can affect the results of this test.

A nurse or lab tech will take a sample of your blood, usually from a vein in your arm. They will first tie a band around the upper part of your arm to make your vein fill with blood and swell up. Then they will clean the area with an antiseptic and place a needle into your vein. Your blood will collect into a vial or tube.

The blood test should take only a couple of minutes. After your blood is taken, the lab tech will remove the needle and band, then put a piece of gauze and a bandage over the spot the needle went in to stop the bleeding.

The ALT blood test is safe. Risks are usually minor, and can include:

• Bleeding
• Bruising
• Infection
• Slight pain when the needle is inserted
• Fainting or feeling dizzy

You should get your results in about a day. A normal ALT test result can range from 7 to 55 units per liter (U/L), but it varies depending on the laboratory used. Levels are normally higher in men.

Slightly high ALT levels may be caused by:

• Alcohol abuse
• Cirrhosis (long-term damage and scarring of the liver)
• Mononucleosis
• Drugs such as statins, aspirin, and some sleep aids

Moderately high ALT levels may be because of:

• Chronic (ongoing) liver disease
• Alcohol abuse
• Cirrhosis
• Blockage of the bile ducts
• Heart attack or heart failure (when your heart can’t pump enough blood to your body)
• Kidney damage
• Muscle injury
• Damage to red blood cells
• Heat stroke
• Too much vitamin A

Very high ALT levels can be caused by:

• Acute viral hepatitis
• An overdose of drugs such as acetaminophen (Tylenol)
• Liver cancer
• Sepsis

ALT usually is done as part of a group of liver function tests called a liver panel.

This panel also includes an aspartate aminotransferase (AST) test. AST is another liver enzyme. As with ALT, the levels of AST in your blood rise if your liver is damaged.

Comparing ALT with AST levels gives your doctor more information about the health of your liver. The AST-to-ASL ratio can help your doctor figure out how severe the liver damage is and what might have caused it.

To find out what type of liver disease you have, your doctor might also test the levels of other enzymes and proteins found in your liver, including:

• Albumin
• Alkaline phosphatase
• Bilirubin
• Lactate dehydrogenase (LDH)
• Total protein
• GGT

Talk to your doctor to make sure you understand all of your liver test results. Also find out how these results might affect your treatment.

Top Picks

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.
• In hepatitis, ALT can be increased by 20-50 times, as liver cells are actively destroyed. For example, in hepatitis A, there is a moderate increase in ALT several weeks before the onset of characteristic symptoms. This enables doctors to stop the development of the disease in a timely manner.
  Cirrhosis of the liver, in which hepatocytes die and connective tissues appear in their place, also causes a sharp increase in ALT.
• An increase in ALT in oncological diseases may indicate liver metastases, but this is not necessary.
• ALT increases in myocardial infarction, since alanine aminotransferase is found not only in the liver, but also in the heart. With myocardial damage, part of the muscle dies, and transaminases enter the bloodstream.