Not enough older adults are getting tested for HIV, according to a recent study.

Researchers at the University of California-Los Angeles (UCLA) found that levels of engagement in HIV risk behaviors remained constant, yet testing decreased among adults ages 50 through 64.

For the study, researchers examined HIV testing trends among adults ages 50 through 64 years both before and after 2006, when the Centers for Disease Control and Prevention (CDC) recommended that most doctors automatically screen all patients for HIV regardless of whether they have symptoms.

The researchers found that gains in HIV testing were not sustained over time. Among this age group, testing decreased from 5.5 percent in 2003 to 3.6 percent in 2006.

It increased immediately after the CDC's recommendation to about 4.5 percent, but then fell to 3.7 percent after 2009. Testing increased over this period only among non-Hispanic blacks and those with a recent doctor visit.

This is one of two recent studies by the same group of researchers into HIV testing among older adults. The previous study found that HIV testing prevalence was less than 5 percent, varied by race and ethnicity, and decreased with age, with the oldest older adults, whites, and older women least likely to be tested.

The findings, which are detailed in the journal Public Health Reports, highlight the fact that more than 90 percent of people in this age group, with whom they are most likely to develop sexual or social relationships, are not receiving HIV screening as the CDC recommends.