Latex specific IgE: performance characteristics of the IMMULITE 2000 3gAllergy assay compared with skin testing.
BACKGROUND
In the absence of a US Food and Drug Administration (FDA)-cleared latex skin testing reagent, in vitro tests remain important for the diagnosis of latex allergy.


OBJECTIVE
To evaluate the performance characteristics of IMMULITE 2000 3gAllergy (Immulite), a third-generation, FDA-cleared, continuous random-access immunoanalyzer, for the quantification of latex specific IgE.


METHODS
Stored serum samples (N = 201) from patients classified as having positive or negative latex puncture skin test results were measured for latex specific IgE levels using Immulite, and these data were compared with historical results from 3 second-generation, FDA-cleared IgE antilatex assays (AlaSTAT [Ala], AutoCAP [CAP], and HY*TEC enzyme immunoassay [HT]).


RESULTS
The diagnostic performances of the CAP, Ala, and Immulite assays (> or = 0.35 kU/L cutoff value) were equivalent in sensitivity and specificity (P > .05). The HT assay (> or = 0.05 kU/L cutoff value) was more sensitive and less specific (P < .05). Immulite (> or = 0.10 kU/L cutoff value) had greater sensitivity than Ala and CAP and greater specificity than HT (P < .05 for both). Diagnostic efficiency was greater for Immulite than for CAP, Ala, and HT (P < .05).


CONCLUSIONS
The Immulite system is superior in diagnostic performance, especially at the 0.10 kU/L or greater cutoff level, for the diagnosis of latex allergy compared with older, second-generation assays. Immulite still misclassifies 15.5% of puncture skin test-positive individuals as negative for latex specific IgE. Compared with second-generation assays, Immulite represents a technological advance, with enhanced speed and less operator intervention.
Biagini
Raymond E
RE
Biomonitoring Research Team, Biomonitoring and Health Assessment Branch, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio 45226, USA. rbiagini@cdc.gov
MacKenzie
Barbara A
BA
Sammons
Deborah L
DL
Smith
Jerome P
JP
Krieg
Edward F
EF
Robertson
Shirley A
SA
Hamilton
Robert G
RG
D006801:Humans; D007124:Immunoenzyme Techniques; D007073:Immunoglobulin E / Q000097:blood*; D020315:Latex Hypersensitivity / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012882:Skin Tests; D013997:Time Factors
D007073:Immunoglobulin E