Five years ago, study findings published in the Journal of the American Academy of Dermatology concluded that tattooing and body piercing are associated with risk-taking activities. Here’s a risk to be aware of: If the conditions for getting a tattoo or piercing are unsanitary, this ups the likelihood of contracting hepatitis C, among other communicable diseases.

Hepatitis C is a contagious liver disease that’s caused by the hepatitis C virus (HCV). People can contract the disease when they come into contact with infected blood. But many infected people never show symptoms of the disease so they are unaware they contracted it. “Hepatitis C is a very sneaky virus,” says Phyllis Ritchie, MD, an infectious disease specialist with a private practice in Portland, Oregon. “In the early stages of acquiring the virus, most people don’t even know they have it.” (Later stages can include scarring of the liver, called cirrhosis, and even liver failure. But some people may never get sick from their HCV.)

Hepatitis C can be transmitted through intravenous drug use, a dirty needle stick in a hospital setting or tattoo parlor, through blood transfusions and possibly sexual activity, although a number of studies conclude that chances of sexual transmission are extremely low.

“Any of those things can get the hepatitis C virus in the bloodstream,” says Jonathan McCone, MD, in private practice in Alexandria, Virginia. “Once there, it doesn’t go away.”

Research from the American Association for the Study of Liver Diseases found that out of 3,871 people studied (half with hepatitis C and half without), those with hepatitis C were about three times more likely to have tattoos.

“If people want a tattoo, they must make sure the establishment is licensed, uses clean needles and observes hygienic sanitizing procedures,” Ritchie advises. (The preferred sterilization device for tattoo equipment is an instrument called an autoclave.)

In addition, no matter where people eventually get “carved,” all materials used to produce a tat—such as ointments, tattoo ink, needles, gloves, trays and any other items that come into contact with blood shed during the tattooing process—should be used just once and tossed into a puncture-proof container. And these precautions also apply to prisoners. Inmates aren’t free to visit tattoo parlors, but many use skin art to express themselves.

In short, everything tattoo artists use should be sterilized and uncontaminated. If you’re worried, get tested to find out your status. And here’s some good news.

The U.S. Food and Drug Administration recently approved two effective HCV treatment drugs—Incivek (telaprevir) and Victrelis (boceprevir). The meds are used with current hep C treatment, but doctors found that Victrelis doubled the HCV cure rate among African Americans.