Rapid diagnosis of adenoviral conjunctivitis on conjunctival swabs by 10-minute immunochromatography.

Purpose: Several methods are available for the diagnosis of acute conjunctivitis, all of which are time-consuming or require the use of a well-equipped laboratory. A new method, immunochromatography (IC), for detecting the presence of adenovirus (Ad) has been developed. Two direct rapid tests to detect Ad antigen, IC and enzyme immunoassay (EIA), were compared with regard to sensitivity, specificity, and technical complexity.
Methods: The study materials consisted of 130 swabs from patients with conjunctivitis (95 samples of adenoviral conjunctivitis proven by positive virus DNA on polymerase chain reaction [PCR], 35 samples of nonadenoviral conjunctivitis proven by PCR). IC is a one-step procedure that detects the presence of adenoviral antigen by sandwich EIA on a paper disc.
Results: In 95 adenoviral DNA-positive samples by PCR, the sensitivity and specificity of IC were 54.7% and 97.1%, respectively, whereas those of EIA were 50.5% and 100%, respectively. By IC, PCR-positive Ad type 3 was recognized in 31%; Ad4 in 100%; Ad7 in 60%; Ad8 in 67%; and Ad37 in 59%, showing similar positivity rates for different serotypes (except Ad7) to those using EIA. Visual determination of the presence of Ad took an average of 10 minutes by IC compared with 70 minutes by EIA.
Conclusions: These results indicate that IC is a more rapid and easier test compared with EIA, and it has high specificity. Detection of Ad antigen by this simple and rapid method will serve physicians as a useful tool for early diagnosis and prevention of adenoviral conjunctivitis.