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Lab test alt normal range: High, Low & Normal Results, Symptoms & Causes

ALT (SGPT) Test – Tufts Medical Center Community Care

What is the ALT test?

This blood test measures an enzyme called alanine transaminase (ALT). Enzymes are chemicals that help the cells of your body work. ALT is an enzyme made in the liver. It is released into the blood when tissues are damaged.

This enzyme is also called serum glutamic-pyruvic transaminase, or SGPT.

Why is this test done?

The ALT test checks for and measures damage to the liver. It is also done to check medical treatments that may affect the liver.

How do I prepare for this test?

  • You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Ask your provider before stopping any of your regular medicines.
  • Talk to your healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. A small amount of blood is taken from a vein in your arm with a needle. The blood is collected in tubes and sent to a lab.

Ask your healthcare provider when and how you will get the result of the test.

What does the test result mean?

Some of the reasons your ALT level may be much higher than normal (up to 50 times the upper limit of normal) are:

  • You have liver damage from an acute viral infection such as hepatitis.
  • You have liver damage caused by medicines you have taken.

Your ALT levels may be higher than normal also if:

  • You drink too much alcohol.
  • You have mononucleosis.
  • You have liver or gallbladder disease, such as gallstones, liver cancer, or liver failure.
  • You have a muscle injury.
  • You are taking a medicine that affects the test result.

No medical problems are known to cause an ALT level that is lower than normal. Sometimes the test result may be lower than normal but it does not mean there is a problem.

What if my test result is not normal?

Test results are only one part of a larger picture that takes into account your medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about the results and ask questions, such as:

  • If you need more tests
  • What kind of treatment you might need
  • What lifestyle, diet, or other changes you might need to make

Adult Advisor 2015.1 published by RelayHealth.
Last modified: 2013-10-18
Last reviewed: 2014-02-03

This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.

Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.

Alanine Aminotransferase Exeter Clinical Laboratory International

Alanine Aminotransferase Exeter Clinical Laboratory International

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Reference Range

  • Male 10 – 41
  • Female 10 – 33

Test Usage

Alanine aminotransferase is an enzyme involved in the transfer of an amino group from the amino acid, alanine, to alpha-ketoglutaric acid to produce glutamate and pyruvate. ALT is located primarily in liver and kidney, with lesser amounts in heart and skeletal muscle. Increased ALT activity is more specific for liver damage than increased aspartate aminotransferase (AST) activity. ALT is seldom increased in patients with heart or muscle disease in the absence of liver involvement. In healthy children, plasma ALT activity is lower than AST until 15 to 20 years of age. Thereafter, plasma ALT activity tends to be higher than AST activity until age 60, when the activities become roughly equal. The half-life of ALT in the circulation is 47 +/- 10 hours.

ALT activity in the liver is 3000 fold higher than in serum. Measurement of serum ALT activity is a good indicator of hepatocyte injury.

DiseasePeak ALT
Peak BilirubinProtime
Viral hepatitis10 – 40<1<15<3
Alcoholic hepatitis2 – 8>2<151 – 3
Toxic injury>40>1 early<5>5 transient
Ischaemic injury>40>1 early<5>5 transient

X ULN = times upper limit of normal, Protime prolongation is number of seconds above ULN

  • The best ALT discriminant value for recognizing acute hepatic injury is 300 U/L.
  • ALT increases before & peak near onset of jaundice in viral hepatitis. Activity falls slowly, an average of 10% per day. ALT remains elevated 27 +/- 16 days.
  • ALT levels fluctuate between normal and abnormal in hepatitis C. 15 to 50% of patients with chronic hepatitis C have persistently normal ALT.
  • In uncomplicated alcoholic hepatitis, ALT values are almost never >10 times the upper reference limit.
  • Extremely elevated ALT levels are common in toxic hepatitis and hepatic ischemia secondary to circulatory collapse and heatstroke. 90% of cases with ALT >3000 U/L are due to toxic or ischemic injury. AST is usually higher than ALT and both enzymes peak in the first 24 hours after admission. After peaking, both levels fall rapidly; AST faster than ALT.
  • Peak ALT levels bear no relationship to prognosis and may fall with worsening of the patients condition. In fulminant hepatic necrosis, decreasing ALT may signify a paucity of viable hepatocytes rather than recovery.

Patients with cirrhosis, non-alcoholic steatohepatitis, cholestatic liver disease, fatty liver and hepatic neoplasm typically have slightly raised serum ALT levels ( < 120 U/L). Patients with cirrhosis seldom have ALT levels higher than two times normal. Cirrhotic patients without ongoing liver injury the values may have normal values.

Other causes of elevated ALT include haemochromatosis, Wilson disease, autoimmune hepatitis, primary biliary cirrhosis, sclerosing cholangitis and alpha-1 antitrypsin deficiency. The medications most commonly associated with elevated ALT are sulfonamides, statins and isoniazid.

Helpful articles:

Pratt & Kaplan, NEJM 2000; 342: 1266-71 Evaluation of abnormal liver-enzyme results in asymptomatic patients

Dufour et al., Clin Chem 2000; 46: 2050-68 Diagnosis and monitoring of hepatic injury. II. Recommendations for use of laboratory tests in screening, diagnosis, and monitoring

Turnaround Time

1 day



Can be added on to an existing request up to 4 days following sample receipt


Please note this test is not UKAS accredited

Specimen Labelling Procedure

General and specific IgE.

Diseases and conditions accompanied by changes in the content of total IgE

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12 October

Immunoglobulin E (IgE) is a class of immunoglobulins found normally in small amounts in blood serum and secretions. IgE was isolated for the first time in 1960s from the sera of patients with atopy and multiple myeloma. In 1968, WHO identified IgE as an independent class of immunoglobulins. According to WHO, 1 IU / ml (IU – international unit) corresponds to 2.4 ng. Usually the concentration of IgE is expressed in IU / ml or kU / l (kU – kilounit).

Normally, IgE is less than 0.001% of all serum immunoglobulins (see Table 1).

Table 1: The content of IgE in the blood serum of healthy people

Age groups IgE (ke/l)
Up to 1 year 0 – 15
1 year-6 years 0 – 60
6 -10 years 0 – 90
10 -16 years old 0 – 200
adults 0 – 100

The structure of IgE is similar to that of other immunoglobulins and consists of two heavy and two light polypeptide chains. They are grouped into complexes called domains. Each domain contains approximately 110 amino acids. IgE has five such domains, in contrast to IgG, which has only four. According to the physicochemical properties, IgE is a glycoprotein with a molecular weight of approximately 1

daltons, consisting of 12% carbohydrates. IgE has the shortest lifespan (half-life from blood serum 2-3 days), the highest rate of catabolism and the lowest rate of synthesis of all immunoglobulins (2.3 µg/kg per day). IgE is synthesized mainly by plasma cells localized in the mucous membranes. The main biological role of IgE is the unique ability to bind to the surface of human mast cells and basophils. On the surface of one basophil there are approximately 40,000 – 100,000 receptors that bind from 5,000 to 40,000 IgE molecules.

Degranulation of mast cells and basophils occurs when two IgE molecules associated with the cell membrane bind to an antigen, which in turn “turns on” successive events leading to the release of inflammatory mediators.

In addition to being involved in type I (immediate) allergic reactions, IgE is involved in protective helminthic immunity, which is due to the existence of cross-linking between IgE and the helminth antigen. The latter penetrates the mucosal membrane and sits on mast cells, causing their degranulation. Inflammatory mediators increase capillary and mucosal permeability, resulting in IgG and leukocytes leaving the bloodstream. IgG-coated helminths are joined by eosinophils, which eject the contents of their granules and thus kill the helminths.

IgE can be detected in the human body as early as the 11th week of fetal development. The content of IgE in the blood serum increases gradually from the moment of birth of a person until adolescence. IgE levels may decrease with age.

In the practice of clinical diagnostic laboratories, the determination of general and specific IgE is carried out in order to use them as independent diagnostic indicators. In table. 2 lists the main diseases and conditions accompanied by a change in the content of total IgE in blood serum.

Table 2: Diseases and conditions associated with changes in total serum IgE

Diseases and conditions Possible reasons
I. Increased content of IgE
Allergic diseases due to IgE antibodies:
a) Atopic diseases
Allergic rhinitis
· Atopic bronchial asthma
Atopic dermatitis
Allergic gastroenteropathy
b) Anaphylactic diseases
Systemic anaphylaxis
Urticaria – angioedema
Multiple allergens:
medicinal preparations
foreign protein
Allergic bronchopulmonary aspergillosis Unknown
Helminthiases IgE antibodies associated with protective immunity
Hyper-IgE syndrome (Job’s syndrome) T-suppressor defect
Selective IgA deficiency T-suppressor defect
Wiskott-Aldridge Syndrome Unknown
Thymus aplasia (DiGeorge syndrome) Unknown
IgE – myeloma IgE-producing plasma cell neoplasia
graft-versus-host disease T-suppressor defect
II. Decreased total IgE
Ataxia – telangiectasia T cell defects

Below are given as examples the ranges of total IgE serum levels (in adults) in some pathological conditions (Table 3). However, despite the initial apparent ease of using the determination of total and specific IgE for diagnosis, there are some difficulties in interpreting the results. Their list is given below.

Table 3: Total IgE values ​​in some pathological conditions

Pathological conditions IgE content (ke/l)
allergic rhinitis 120 – 1000 kU/l
Atopic bronchial asthma 120 – 1200 kU/l
Atopic dermatitis 80 – 14000 kU/l
Allergic bronchopulmonary aspergillosis:
– remission
– aggravation
80 – 1000 kU/l
1000 – 8000 kU/l
Hyper – IgE syndrome 1000 – 14000 kU/l
IgE – myeloma 15000 kU/l and above

Features of interpretation and diagnostic limitations of total IgE

  • Approximately 30% of patients with atopic diseases have a level of total IgE within the normal range.
  • Some people with asthma may have hypersensitivity to only one allergen (antigen), resulting in total IgE being in the normal range, while skin testing and specific IgE will be positive.
  • The concentration of total IgE in the blood serum also increases in non-atopic conditions (especially with helminthic invasion, some forms of immunodeficiency and bronchopulmonary aspergillosis) with subsequent normalization after appropriate treatment.
  • Chronic recurrent urticaria and angioedema are not mandatory indications for the determination of total IgE, as they are usually non-immune in nature.
  • The normal limits defined for Europeans cannot be applied to representatives of areas endemic for helminthiases.

Features of interpretation and diagnostic limitations of specific IgE

  • Availability of specific IgE determination should not exaggerate its diagnostic role in the examination of patients with allergies.
  • Detection of allergen-specific IgE (to any allergen or antigen) does not prove that this particular allergen is responsible for clinical symptoms; the final conclusion and interpretation of laboratory data should be made only after comparison with the clinical picture and the data of a detailed allergic history.
  • The absence of specific IgE in peripheral blood serum does not exclude the possibility of an IgE-dependent mechanism, since local IgE synthesis and mast cell sensitization can occur in the absence of specific IgE in the bloodstream (for example, allergic rhinitis).
  • Antibodies of other classes specific for this allergen, especially the class IgG (IgG4), may cause false negative results.
  • Exceptionally high concentrations of total IgE, for example, in individual patients with atopic dermatitis, may, due to non-specific binding to the allergen, give false positive results.
  • Identical results for different allergens do not imply the same clinical significance, since the ability to bind to IgE in different allergens may be different.
    In conclusion, taking into account all of the above, as well as the existing difficulties in the formulation and interpretation of skin tests, we list the main indications and contraindications for the appointment of a specific allergological examination in vitro – the determination of specific IgE (Table 4).

    Table 4: Indications and contraindications for specific IgE testing

    1 Differential diagnosis between IgE-dependent and non-IgE-dependent mechanisms of allergic reactions
    2 Patients in whom it is impossible to identify the allergen by anamnestic history, using a diary, etc.
    3 Patients with insufficient effect of specific hyposensitization prescribed based on the results of skin tests
    4 Dermographism and widespread dermatitis
    5 Patients of childhood and the elderly with skin hyporeactivity
    6 Skin hyperreactivity
    7 Patients who cannot stop symptomatic therapy with drugs that affect the results of skin tests
    8 Negative attitude of the patient to skin tests
    9 History of systemic allergic reactions to skin tests
    10 Inconsistency of the results of skin tests with the data of the anamnesis and the clinical picture
    eleven IgE-dependent food allergy
    12 The need to quantify the sensitivity and specificity of the allergen
    13 Total IgE of blood serum more than 100 kU/l
    Examination is inappropriate:
    1 In atopic diseases in cases of satisfactory results of specific therapy according to skin tests
    2 In patients with a non-IgE-dependent mechanism of an allergic reaction

    Related links: Immunoglobulin E, IgE general (allergodiagnostics), allergen panels.


    1. Macharadze D.Sh. Modern clinical aspects of assessing the levels of general and specific IgE // Pediatrics. 2017; 96(2): 121-127.
    2. Rybnikova E.A., Prodeus A.P., Fedoskova T.G. Modern approaches to the laboratory diagnosis of allergies – to help the practitioner // BC. Medical review. – No. 1 dated 04/26/2021. – pp. 43-49. DOI: 10.32364/2587-6821-2021-5-1-43-49


    The information in this section should not be used for self-diagnosis or self-treatment. In case of pain or other exacerbation of the disease, only the attending physician should prescribe diagnostic tests. For diagnosis and proper treatment, you should contact your doctor.
    For a correct assessment of the results of your analyzes over time, it is preferable to do studies in the same laboratory, since different laboratories may use different research methods and units of measurement to perform the same analysis.


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