DIAGNOSTIC TEST FOR DRUG ALLERGY

DIAGNOSTIC TEST FOR DRUG ALLERGY

Test For Immediate Reaction

Skin Prick Test (SPT) SpecificSensitiveSimple to performRapid (result in 15-20 min)Educational for patient

procedure

Panduan PPK RSUP DR. SardjitoProsedur patch test

Prosedur skin prick test

Prosedur tes provokasi obat

Intradermal Skin Test (IDT)More sensitive than skin prick testMay induce false positive reactionsMay induce systemic reactionsShould be done only if skin prick test is negative and allergen is highly suspect.

prosedur

Immediate reactionsDrug specific IgE TestsCommercially availablePhadia CAP/ ImmunoCAP (fluorescent enzyme immunoassay, FEIA)Penicilloyl G, penicilloyl V, suxamethonium

Less sensitive and more expensive compared to skin testingSensitivity for penicillins/ amoxycillin from 38-54%Specificity for penicillins/ amoxicillin from 87-100%

ResultsReported as kU/LPositive 0.7 kU/L (Class 2)

Patient IgEAllergen coupled toImmunoCAPConjugate;Enzyme Anti-IgEPatient IgE ab bound toImmunoCAP allergenFluorogenic substrateConjugate bound topatient IgEConjugate enzyme reacts withsubstrate forming a fluorescent product

Illustration of a Widely Used Assay (ImmunoCAP System) for Allergen Specific IgE Quantificationprocedure

14Please title the slide

Immediate reactions Flow CASTFlow cytometric basophil activation test (FAST, FLOW-CAST or BASOTEST) Based on the flow cytometric evaluation of CD63 on blood basophils, an activation molecule appearing following incubation of blood basophils with drugs or other allergens in vitro -lactams:Sensitivity 50%, specificity 93% when compared with FEIAGreater sensitivity and specificity than FEIA (37.9% and 86.7% respectively)Combination of FAST and FEIA allows identification of 65-80% of penicillin allergic individuals.NSAIDs: sensitivity 71-76%Positive Test: > 15% CD63+ (Stimulation Index 2)

Immediate reactionsCASTCellular Allergen Stimulation test (CAST)-ELISASulphidoleukotrienes (LTC4 and its metabolites LTD4 and LTE4) produced upon in vitro stimulation of blood leukocytes (predominantly basophils) by drugs are quantitatively measured -lactams:Sensitivity 46% (range 3580%)Specificity between 79 and 89%.

Test For Delayed Reaction

Delayed reactionsLymphocyte transformation test (LTT)Measures the proliferation of T cells to a drug in vitroAdvantage:Applicable to many different drugs with different immune reactions, as drug-specific T cell are almost always involved in drug hypersensitivity reactionsDisadvantages:Test per se is rather cumbersome and technically demandingSensitivity is limitedPicher WJ, et al. Allergy 2004: 59: 809820

LTT LTT frequently positive (>50%)Generalized maculopapular exanthemaBullous exanthemaAcute generalized exathematous pustulosis (AGEP)DHS/drug hypersensitivity syndrome with eosinophilia and systemic symptoms (DRESS)Anaphylaxis (generalized, severe symptoms)

LTT occasionally positiveHepatitis (dependent on type of drug)Nephritis (dependent on type of drug)Urticaria, angioedemaInterstitial lung disease*Pancreatitis*

LTT rarely positive (