Detecting injuries in criminal cases such as sexual assault or domestic violence is difficult for darker-skinned victims using the standard white light commonly found in exam rooms. The answer to this problem may lie in using alternate light sources, a new study shows.

The study, led by researchers at Virginia's George Mason University, in collaboration with Texas A&M University, analyzed more than 31,000 samples of bruised areas on the arm belonging to individuals having a range of skin colors. The blue or purple light was five times better at spotting bruises on people with darker skin when compared to white light, CNN reported.

According to Katherine Scafide, the study’s lead researcher and an associate professor of nursing at George Mason University, mostly used fluorescent lighting in exam rooms is not effective in spotting bruises on patients with darker skin.

“The issue is that for these types of individuals, unfortunately, if you can’t see the injury, you can’t document it well and then you have less evidence for these victims in court,” Scafide, who also worked as a forensic nurse for several years.

In the study, volunteers were shot with a paintball gun to create consistent bruises, and then those bruises were documented using an alternate light source, the National Institute of Justice reported.

Scafide said the equipment is often used by the police to look for latent physical evidence, such as blood and fibers at crime scenes, but it is not being used to look at injuries on victims.

Researchers are in the middle of developing guidelines that are “evidence-based,” “patient-centered” and “trauma-informed” for forensic nurses. The guidelines are expected to be finalized by June end.

“My hope is that the equipment will be more widely adopted after the release of the clinical practice guidelines. However, I’m cautious about them being used by law enforcement, unless to encourage victims to seek an exam by a forensic health care provider,” Scafide commented.

This is not the first run-in people with dark skin have had with technology created by keeping white people in mind. Medical literature exposes the shortcomings of some of the devices--forehead thermometers and pulse oximeters--that did not work as well as they should have in Black patients.

“The fact that our traditional methodologies were developed for people with White skin meant that these nurse practitioners could not detect reported abuse accurately,” Nancy La Vigne, director of the National Institute of Justice, told CNN. “There is a better methodology out there for women with dark skin pigmentation and we need to distribute it throughout the country so that there’s no excuse to not use the right equipment for the right women.”

However, even with the right equipment, mistakes are bound to happen without the right guidance, Nancy Downing, an associate professor at the Center for Excellence in Forensic Nursing at Texas A&M University and co-author of the study, said.

“There are other reasons why people might have absorption under light, including birthmarks and reaction to some topical products, which we found in the study,” Downing noted. “It should only be used in combination with a known site of trauma or impact.”