Conducting HIV tests on inmates as they enter prison may not actually turn up more than a scant number of undiagnosed cases, MedPage Today reports. Publishing their results in the Journal of the American Medical Association, researchers conducted HIV tests on samples of blood that inmates had provided for a mandatory syphilis test upon their entry into the North Carolina system between June 2008 and April 2009.

Out of the 23,373 inmates, 22,134 provided enough extra blood for the researchers to run an HIV test. The researchers identified that 320 (1.45 percent) were HIV positive. Only 20 of this total, however, (0.09 percent) were not already known to be positive when they entered prison.

The prevalence of the virus among the new inmates was about 1.43 percent, which is close to the Centers for Disease Control and Prevention’s (CDC) estimate of a national prison prevalence of 1.4 percent.

To read the MedPage Today story, click here.

To read the study abstract, click here.