Sorted By Test Name - Mayo Medical Laboratories

AST
8360
clinical manifestations. In individuals predisposed to develop allergic disease(s), the sequence of
sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and
bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat
proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to
sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).
Useful For: Testing for IgE antibodies may be useful to establish the diagnosis of an allergic disease
and to define the allergens responsible for eliciting signs and symptoms. Testing also may be useful to
identify allergens which may be responsible for allergic disease and/or anaphylactic episode, to confirm
sensitization to particular allergens prior to beginning immunotherapy, and to investigate the specificity of
allergic reactions to insect venom allergens, drugs, or chemical allergens.
Interpretation: Detection of IgE antibodies in serum (Class 1 or greater) indicates an increased
likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be
responsible for eliciting signs and symptoms. The level of IgE antibodies in serum varies directly with the
concentration of IgE antibodies expressed as a class score or kU/L.
Reference Values:
Class IgE kU/L Interpretation
0 Negative
1 0.35-0.69 Equivocal
2 0.70-3.49 Positive
3 3.50-17.4 Positive
4 17.5-49.9 Strongly positive
5 50.0-99.9 Strongly positive
6 > or =100 Strongly positive Reference values
apply to all ages.
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by
Laboratory Methods. 21st edition. Edited by RA McPherson, MR Pincus. New York, WB Saunders
Company, 2007, Chapter 53, Part VI, pp 961-971
Aspartate Aminotransferase (AST) (GOT), Serum
Clinical Information: AST is found in high concentrations in liver, heart, skeletal muscle and kidney.
AST is present in both cytoplasm and mitochondria of cells. In cases involving mild tissue injury, the
predominant form of AST is that from the cytoplasm. Severe tissue damage results in more of the
mitochondrial enzyme being released. High levels of AST can be found in cases such as myocardial
infarction, acute liver cell damage, viral hepatitis and carbon tetrachloride poisoning. Slight to moderate
elevation of AST is seen in muscular dystrophy, dermatomyositis, acute pancreatitis and crushed muscle
injuries.
Useful For: The determination of AST is most often used in diagnosing and monitoring liver disease,
particularly diseases resulting in a destruction of hepatocytes
Interpretation: Elevated AST values are seen in parenchymal liver diseases characterized by a
destruction of hepatocytes. Values are typically at least 10 times above the normal range. Levels may
reach values as high as one hundred times the upper reference limit, although twenty to fifty-fold
elevations are most frequently encountered. In infectious hepatitis and other inflammatory conditions
affecting the liver, ALT is characteristically as high as or higher than AST, and the ALT/AST ratio, which
normally and in other condition is less than 1, becomes greater than unity. AST levels are usually elevated
before clinical signs and symptoms of disease appear. Five to ten-fold elevations of both AST and ALT
occur in patients with primary or metastatic carcinoma of the liver, with AST usually being higher than
ALT, but levels are often normal in the early stages of malignant infiltration of the liver. Elevations of
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