Evaluation of the opioid addiction test in an out-patient drug dependency unit

The opioid addiction test is based on the measurement of pupil dilatation in opioid-dependent people in response to conjunctivally applied naloxone hydrochloride. A positive response (pupil dilatation) indicates that the subject is dependent on opioids.

To evaluate the test in an out-patient setting and to identify factors affecting its outcome.

Pupil size was measured using binocular pupillometry in 100 new patients attending an out-patient clinic for assessment and treatment of opioid use. Measurement was repeated 40 minutes after the unilateral instillation of naloxone drops into the conjunctival sac.

We performed 127 tests, of which 103 (81.1%) were positive. Males, and those not on methadone at the time of the test, were more likely to have a negative test result.

The opioid addiction test proved to be a very useful tool for the rapid diagnosis of opioid dependence in the out-patient clinic. Specialist pupillometric equipment increases the number of patients correctly identified as opioid-dependent on the first visit, but is not essential.