Relationship between Total Tear and Serum IgE in Allergic Conjunctivitis

Background: Recently, a new commercial test for total tear IgE based on immunochromatography (Allerwatch®) was developed. We examined the relationship between total tear and serum IgE levels with the Allerwatch test. Methods: A nonrandomized cross-sectional study was conducted in 40 patients with allergic conjunctivitis, 35 age- and sex-matched healthy control subjects, and 6 patients with epidemic keratoconjunctivitis (EKC). The total tear IgE score was determined with the Allerwatch test (0, 1 and 2), and the serum total IgE level was measured by solid-phase immunoassay (Phadezym PRIST) in all subjects. Results: Total tear IgE was assayed within 10 min of collection in all samples. The total tear IgE-positive rate was significantly higher in the allergic group than in the control and EKC groups (92.5 vs. 0.0 vs. 0.0%; p < 0.00001). Sensitivity and specificity were 0.925 and 1.000, respectively. The total IgE score and log (total serum IgE) were also higher in the allergic group than in the control and EKC groups [total IgE score: 1.48 ± 0.63 vs. 0.00 ± 0.00 vs. 0.00 ± 0.00, p < 0.00001; log (serum total IgE): 2.23 ± 0.50 vs. 0.80 ± 0.31 vs. 0.79 ± 0.37, p < 0.00001]. The total tear IgE score was significantly correlated with log (total serum IgE) in the allergic group (r = 0.712, p < 0.00001). Conclusions: These results show that this rapid test for the measurement of total tear IgE is easy to perform on an outpatient basis and may be helpful in the management of ocular allergy.