Sorted By Test Name - Mayo Medical Laboratories

DHEA_
81405
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 McPherson RA, Pincus MR. WB Saunders, Publ, New York,
Chapter 53, Part VI, pp. 961-971, 2007
Dehydroepiandrosterone (DHEA), Serum
Clinical Information: Dehydroepiandrosterone (DHEA) is the principal human C-19 steroid. DHEA
has very low androgenic potency, but serves as the major direct or indirect precursor for most sex steroids.
DHEA is secreted by the adrenal gland and production is at least partly controlled by adrenocorticotropic
hormone (ACTH). The bulk of DHEA is secreted as a 3-sulfoconjugate dehydroepiandrosterone sulfate
(DHEAS). Both hormones are albumin bound, but DHEAS binding is much tighter. As a result,
circulating concentrations of DHEAS are much higher (>100-fold) compared to DHEA. In most clinical
situations, DHEA and DHEAS results can be used interchangeably. In gonads and several other tissues,
most notably skin, steroid sulfatases can convert DHEAS back to DHEA, which can then be metabolized
to stronger androgens and to estrogens. During pregnancy, DHEA/DHEAS and their 16-hydroxylated
metabolites are secreted by the fetal adrenal gland in large quantities. They serve as precursors for
placental production of the dominant pregnancy estrogen, estriol. Within weeks after birth,
DHEA/DHEAS levels fall by 80% or more and remain low until the onset of adrenarche at age 7 or 8 in
girls and age 8 or 9 in boys. Adrenarche is a poorly understood phenomenon, peculiar to higher primates,
that is characterized by a gradual rise in adrenal androgen production. It precedes puberty, but is not
casually linked to it. Early adrenarche is not associated with early puberty or with any reduction in final
height or overt androgenization. However, girls with early adrenarche may be at increased risk of
polycystic ovarian syndrome as adults and some boys may develop early penile enlargement. Following
adrenarche, DHEA/DHEAS levels increase until the age of 20 to a maximum roughly comparable to that
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