Sorted By Test Name - Mayo Medical Laboratories

CHAG
86159
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
Trypanosoma cruzi Antibody, IgG, Serum
Clinical Information: Chagas disease (American trypanosomiasis) is an acute and chronic infection
caused by the protozoan hemoflagellate, Trypanosoma cruzi which is endemic in many areas of South and
Central America. The parasite is usually transmitted by the bite of reduviid (or "kissing") bugs of the
genus Triatoma, but also has been transmitted by blood transfusion, organ transplantation, and apparently
also by food ingestion. The acute febrile infection is most often undiagnosed and often resolves
spontaneously. The actively motile (trypomastigote) form may be demonstrated in peripheral blood by
stained smears during the acute phase. Chronic infections are often asymptomatic but may progress to
produce disabling and life-threatening cardiac (cardiomegaly, conduction defects) and gastrointestinal
(megaesophagus and megacolon) disease. These damaged tissues contain the intracellular (amastigote) of
Trypanosoma cruzi. The parasite is not seen in the blood during the chronic phase. Diagnosis at this time
is made by serology or tissue biopsy. A positive serology is considered presumptive evidence of active
infection. Serologically positive asymptomatic persons are capable of transmitting the infection.
Useful For: Diagnosis of Chagas disease (infection with Trypanosoma cruzi)
Interpretation: A positive serology is considered evidence of active infection. Infected individuals
usually begin producing antibodies to Trypanosoma cruzi during the first month following exposure to the
parasite. Antibody levels may fluctuate during the chronic phase of the disease and may become
undetectable after several months. Uninfected individuals are not expected to have detectable levels of
antibodies to Trypanosoma cruzi.
Reference Values:
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