(NBC) -- Many people use tattoos as a form of personal expression, but a small number of Americans rely on them to warn first responders about important medical conditions.
Some medical tattoos are taking the place of bracelets that commonly list a person's allergies and chronic diseases.
Tattoo artist Mike Martin believes the placement of medical tattoos are extremely important -- he has designed about 100 medical tattoos in his career.
"It has to be spotted. It has to be visible and recognizable for what it means," he says. "It's very personal and it's information that is always guarded."
The markings offer a simple and permanent way to display important health details.
Matt Besley, an avid surfer, was diagnosed with Type 1 diabetes as a kid.
"Over the course of my life, I have had 10 or 15 different bracelets, necklaces," he said. "Surfing all the time I kept losing them."
A few years ago he got a medical tattoo on his right arm.
"Two things are going to happen with a diabetic. When you go into a hypoglycemic episode, they are going to put a dextrose IV in your arm and they are going to take your blood pressure," he said. "So they are going to have your arm out and exposed, so I figured that was a good place to put it."
That tattoo served its purpose.
After surfing longer than he had anticipated, Besley started feeling weak.
"I started making my way into the shore, but I didn't have enough strength at that point because my blood sugar had gotten so low and I was kinda falling into the water," he recalls.
He was scared he was going to drown.
Luckily, witnesses pulled Besley ashore.
"At that point they pulled my wetsuit off and had seen the tattoo," said Besley. "So they knew immediately it was probably related to my diabetes."
Within minutes, lifeguards had given him a dextrose shot.
"By the time they got me onto the pavement, my blood sugars had already corrected themselves," he said.
Medical tattoos don't carry any legal weight in California.
The American Medical Association does not specifically address medical tattoos in its guidelines.
Still, first responders say they are helpful.
"When we show up we are going to find your medical condition with the assessment we do, whether you have the tattoo or not. But, it does give us a hint as to what your medical history is," says paramedic Marc Alnwick.
Health professionals still recommend wearing medical alert tags, which give detailed medical information, but are open to anything that helps save lives.
"We are always adapting to trends in the community," Alnwick said. "So if this became something that is more popular we would then adjust and look for the medical alert tattoos."