Sorted By Test Name - Mayo Medical Laboratories

SCADK
83947
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
Short-Chain Acyl-CoA Dehydrogenase (SCAD) Deficiency,
Known Mutation
Clinical Information: Short-chain acyl-CoA dehydrogenase (SCAD) catalyzes the first step in the
mitochondrial beta-oxidation of fatty acids with a chain length of 6 to 4 carbons. SCAD deficiency is a
rare autosomal recessive condition. The clinical phenotype of SCAD shows considerable variability and is
incompletely defined. Of those reported cases, hypoglycemia, developmental delay, and muscle hypotonia
are the most common indicated features. The diagnosis of SCAD deficiency is challenging and should be
based on the clinical presentation, 2 or more findings of ethylmalonic aciduria, and determination of fatty
acid flux in fibroblasts indicating deficient SCAD activity. Molecular genetic analysis of the gene
associated with SCAD (ACADS) may confirm the biochemical phenotype of SCAD deficiency. The first
step in evaluation for SCAD deficiency is identification of 2 or more findings of ethylmalonic aciduria, as
determined by either OAU/80619 Organic Acids Screen, Urine or ACYLG/81249 Acylglycines,
Quantitative, Urine. Ethylmalonic aciduria is a common, although not specific, laboratory finding in
patients with SCAD deficiency. Determination of fatty acid flux in fibroblasts (FAO/81927 Fatty Acid
Oxidation Probe Assay, Fibroblast Culture) is warranted for an individual with 2 or more findings of
ethylmalonic aciduria. DNA sequencing of the ACADS gene is typically utilized only when SCAD
deficiency is identified through biochemical analysis. The ACADS gene is located on chromosome 12q22
and consists of 10 exons. Molecular genetic studies revealed that some patients carry ACADS gene
mutations that cause complete absence of SCAD activity, while others carry ACADS gene variants
(511C->T;625G->A) that may confer disease susceptibility only in association with other factors. The
allele frequencies in the general population of the 511C->T and 625G->A gene variants are 3% and 22%,
Current as of January 4, 2013 7:15 pm CST 800-533-1710 or 507-266-5700 or MayoMedicalLaboratories.com Page 1592