Sorted By Test Name - Mayo Medical Laboratories

JACK
82371
bioavailability approximates 55% but is highly variable; absorption can be enhanced by food or acidic
drinks. Hepatic enzyme inducers can cause low serum itraconazole levels, and coadministration of these
drugs has been associated with itraconazole therapeutic failure. Itraconazole therapeutic efficacy is
greatest when serum concentrations exceed 0.5 mcg/mL for localized infections, or 1.0 mcg/mL for
systemic infections. An active metabolite, hydroxyitraconazole, is present in serum at roughly twice the
level of the parent drug. These concentrations refer to analysis by HPLC; quantitation by bioassay results
in considerably higher apparent drug measurements, due to reactivity with the active metabolite.
Useful For: Verifying systemic absorption of orally administered itraconazole. The test is indicated in
patients with life-threatening fungal infections and in patients considered at risk for poor absorption or
rapid clearance of itraconazole.
Interpretation: A lower cutoff concentration has not been defined that applies in all cases. The serum
concentration must be interpreted in association with other variables, such as the nature of the infection,
the specific microorganism, and minimal inhibitory concentration (MIC) results, if available. Localized
infections are more likely to respond when serum itraconazole is >0.5 mcg/mL (by HPLC); systemic
infections generally require drug concentrations >1.0 mcg/mL.
Reference Values:
ITRACONAZOLE (TROUGH)
>0.5 mcg/mL (localized infection)
>1 mcg/mL (systemic infection)
HYDROXYITRACONAZOLE
No therapeutic range established; activity and serum concentration are similar to parent drug.
Clinical References: 1. Andes D, Pascual A, Marchetti O: Antifungal therapeutic drug monitoring:
established and emerging indications. Antimicrob Agents Chemother 2009;53(1):24-34 2. Hope WW,
Billaud EM, Lestner J, Denning DW: Therapeutic drug monitoring for triazoles. Curr Opin Infect Dis
2008;21:580-586
Jack Fruit, IgE
Clinical Information: Clinical manifestations of immediate hypersensitivity (allergic) diseases are
caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from
immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE
antibodies interact with allergen. In vitro serum testing for IgE antibodies provides an indication of the
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
Current as of January 4, 2013 7:15 pm CST 800-533-1710 or 507-266-5700 or MayoMedicalLaboratories.com Page 1057