Oxybuprocaine induces a false-positive response in immunochromatographic SAS Adeno Test.

OBJECTIVE

To investigate whether a solution of oxybuprocaine hydrochloride, 0.4%, results in a false-positive response in an immunochromatographic SAS Adeno Test.

DESIGN

Experimental study.

CONTROLS: Physiologic saline and 2% lidocaine.

TESTING: Each chemical (100 microl) was diluted in a transport medium. Five drops (200 microl) of the resultant solution were dispensed into the round sample well of a test device. Fifteen samples were tested in each group.

MAIN OUTCOME MEASURES: Ten minutes after the start of the test, a colored line in the "specimen" portion of the test membrane was visually read as positive or negative by a masked technician.

RESULTS

No positive reaction was observed in the control groups (physiologic saline and lidocaine). A false-positive reaction was observed in six samples (33.3%) in the oxybuprocaine group. The positive rate was significantly higher in the oxybuprocaine group compared with those in control groups (P = 0.0062, Fisher's extract probability test).

CONCLUSIONS

Oxybuprocaine may induce a false-positive reaction in an immunochromatographic SAS Adeno Test. We recommend the use of lidocaine, instead of oxybuprocaine, for local anesthesia in taking eye swabs from patients with suspected adenovirus infection.