Almost 3 in every 1,000 people tested for HIV as part of a screening programme at the Mater Hospital in Dublin were diagnosed with the infection. The rate is regarded as high by international standards.
Widespread screening is recommended for a prevalence of 1 in 1,000.
The results of the Mater-Bronx Rapid HIV Testing Project have been released as part of the 2013 European HIV Testing Week, ahead of World AIDS Day on Sunday.
Patients who choose to participate in the project watch an interactive counselling video, complete an on-screen survey that assesses risk behaviour, and are offered an oral swab test from the mouth - with the results available after approximately 20 minutes.
There has been an upsurge in interest in HIV screening research since the recognition that early identification of HIV infection not only improves the outlook of those with infection but, with effective treatment, this can also prevent onward transmission of HIV.
Dr. Ger O'Connor is one of the doctors in the emergency room. He says the test is non-invasive and the results are fast.