Predictive capacity of histamine release for the diagnosis of drug allergy.
BACKGROUND
The diagnosis of immediate allergic reactions to drugs is difficult, requiring in vitro test development. Basophils are likely to be involved in these reactions, and to evaluate the sensitivity, the specificity, and the predictive values of the histamine-release test, we performed a prospective study in 68 patients tested for suspected drug allergy.


METHODS
Positive diagnosis was established by history, skin tests, and, if needed, oral provocation tests. Histamine release in the presence of the drug was assessed on heparinized whole blood by enzyme immunoassay (Immunotech, France), and the cutoff value was set at 5% of total histamine content. Spontaneous and anti-IgE-induced histamine release was also studied in all subjects.


RESULTS
All patients presented to our clinic with reactions ranging from maculopapular exanthema to anaphylactic shock. Thirty-five patients had proven drug allergy; 33 were not allergic to drugs and served as a control group together with 40 other subjects with no history of drug allergy. Net histamine release was positive in 18/35 allergics and 27/73 nonallergics, giving poor sensitivity (51.4%), specificity (63.0%), and positive predictive value (29.3%), but valuable negative predictive value (81.1%).


CONCLUSIONS
The usefulness of the in vitro histamine-release test for the diagnosis of drug allergy appears to be insufficient.
Demoly
P
P
Maladies Respiratoires, INSERM U454, CHU de Montpellier et Institut Universitaire de Recherche Clinique, France.
Lebel
B
B
Messaad
D
D
Sahla
H
H
Rongier
M
M
Daurès
J P
JP
Godard
P
P
Bousquet
J
J
D000082:Acetaminophen / Q000009:adverse effects; D000293:Adolescent; D000328:Adult; D000368:Aged; D018712:Analgesics, Non-Narcotic / Q000009:adverse effects; D000900:Anti-Bacterial Agents / Q000009:adverse effects; D002648:Child; D004342:Drug Hypersensitivity / Q000175:diagnosis*; D006636:Histamine Release; D006801:Humans; D007124:Immunoenzyme Techniques; D007769:Lactams; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D012882:Skin Tests
D018712:Analgesics, Non-Narcotic; D000900:Anti-Bacterial Agents; D007769:Lactams; D000082:Acetaminophen