TABLE 3.

Role of diagnostic/screening tests in delayed drug hypersensitivity reactions.

	In vivo			Ex vivo
Clinical diagnosis	Patch testing	Delayed IDT	Oral challenge	LTT	ELISpot	HLA
MPE	Yes ♣	Yes ♣	Yes	No	No	No
AGEP	Yes	Yes	No	Equivocal	Equivocal	No
DRESS/DIHS	Yes	Yes	No	Yes	Yes	Yes ψ
SJS/TEN	Yes	No	No	Yes	Yes	Yes ψ
FDE	Yes ω	No	Equivocal	No	No	No
SDRIFE	Yes ω	Equivocal	Equivocal	No	No	No

AGEP, acute generalized exanthematous pustulosis; DIHS, Drug-induced Hypersensitivity syndrome; DRESS, Drug reaction with eosinophilia and systemic symptoms; ELISpot, enzyme-linked immunospot; FDE, fixed drug eruption; HLA, human leukocyte antigen; LTT, Lymphocyte transformation test; SDRIFE, symmetrical drug-related intertriginous and flexural exanthema, SJS/TEN, Stevens-Johnson syndrome/toxic epidermal necrolysis. ♣ As the sensitivity for PT and IDT is poor, drug challenge of the implicated drug can be considered. PT/IDT may give information on cross-reactivity ω PT should be applied on the region of the previous reaction ψ HLA screening is not routinely used globally in clinical practice. Please refer to Table 4 for details.