Sorted By Test Name - Mayo Medical Laboratories

FXYM
86374
immune response to allergen(s) that may be associated with allergic disease. The allergens chosen for
testing often depend upon the age of the patient, history of allergen exposure, season of the year, and
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
Known 45,X, Mosaicism Reflex Analysis, FISH
Clinical Information: Ullrich-Turner syndrome (UTS), also called Turner syndrome, is a genetic
disorder associated with the apparent loss of a sex chromosome. Routine cytogenetic methods have
identified 3 types of chromosomal abnormalities in UTS patients: loss of an entire X chromosome (45,X),
structural X chromosome abnormalities, and mosaicism with an X or Y abnormality. In mosaicism, 2 or
more populations of cells with different karyotypes are present (eg, 45,X/47,XXX). The incidence of UTS
is approximately 1/3,000 newborn girls. Many of these patients demonstrate the 45,X karyotype. About
30% to 50% are mosaic, with either a 45,X/46,XX karyotype or a structurally abnormal X chromosome.
Fewer than 15% of patients with UTS appear to have mosaicism with a 46,XY cell population or a Y
chromosome rearrangement. Identifying the mosaic status of patients with UTS is of clinical importance
because phenotypic expression and clinical management are dependent upon the karyotype result. Patients
with a Y chromosome have a 15% to 25% increased risk of gonadoblastoma.
Useful For: This test provides a sensitive method for identifying sex chromosome mosaicism (ie, low
level detection)
Interpretation: An XX clone is confirmed when > or =1.0% cells display with 2 X chromosome
signals. An XY clone is confirmed when > or =0.6% cells display a 1 X and 1 Y signal pattern. Females
with a 45,X/46,XX karyotype have no increased risk of gonadoblastoma and generally have a more
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