The sting challenge test shows high negative predictive value in
patients receiving venom immunotherapy.
Abstract
Background The sting challenge test (SCT) is regarded as the most
reliable method for assessing the effectiveness of venom immunotherapy
(VIT). However, its predictive value in patients undergoing VIT is still
unclear. This study aims to evaluate the predictive value of the SCT.
Methods A multicenter retrospective observational study was conducted on
patients receiving VIT who underwent SCT. The study gathered data on
patient demographics, diagnosis, immunotherapy details, outcomes of the
SCT and their comparison to subsequent field sting (FS) results. Results
A total of 261 patients were included, and 372 SCT were recorded. The
majority of the patients (75.1%) were men. A diagnosis of mastocytosis
was confirmed in 7.7%. The final diagnoses were allergy to Apis
mellifera (48.7%), Polistes dominula (36.8%), Vespula
spp. (2.7%) and Polistes dominula plus Vespula spp.
(10,7%). Sting challenge tests were performed with Apis in
61.6% of the overall tests, Polistes in 34.1% and
Vespula in 4.3%. The majority (95.7%) of the SCT were negative.
Regarding FS, 146 patients (56.2%) experienced 306 FS of which 95.1%
were negative. Among these 146 patients, 137 had a negative SCT, and 130
of these also had a subsequent negative FS, resulting in a 94.9% of
negative predictive value (NPV) of the test. Of the patients who
experienced FS, 9 had a positive SCT and only 3 of them had a positive
FS, resulting in a positive predictive value of 33,3%. Conclusions SCT
is a safe procedure, and its high NPV emphasizes the usefulness of this
test in assessing the effectiveness of VIT.