WASHINGTON: Few people look forward to a trip to the doctor or dentist, especially if they’re not sure how they will pay for it.

Some choose to use a special kind of credit card offered by medical professionals to pay for care at certain locations or networks. Often pitched by office assistants, they can seem like a quick fix for pricey procedures not covered by insurance including dental work, cosmetic surgery or laser vision correction.

Nearly a third of Americans report trouble paying their medical bills and many have taken on credit card debt to pay the expenses, according to a recent survey by the Kaiser Family Foundation.

But consumer advocates warn medical credit cards can saddle patients with unexpected penalties and sky-high interest rates.

Credit confusion

One of the biggest dangers is that patients often don’t understand the financial terms or even that they are signing up for a credit card, according to lawyers who have represented customers.

“There is a lot of misunderstanding. Patients think they are just setting up an installment plan with the dentist,” said Gina Cala­brese, co-director of St. John’s University School of Law’s Public Interest Center in New York. “They don’t understand they have opened a new line of credit and all the risks involved with that.”

Most cards feature a “zero interest” promotional period of up to 18 months. But then the interest rate can jump to 25 percent or higher.

Surprise interest

Another potential pitfall is something called deferred interest. That means if consumers don’t pay off the entire procedure during the “interest-free” period, they can be retroactively charged for interest dating back to when they first signed up.

For patients who decide to take on medical credit, advocates say it’s essential to pay off the entire borrowed amount within the promotional period.

Trust issues

The rate hikes on medical credit cards are not unique. Credit cards issued by department stores and other retailers often have similar terms. But advocates say consumers tend to be less wary of products offered by medical professionals.

Before signing up for a medical credit card, experts suggest researching other options. If the procedure is not urgent, consider waiting until a later date and paying cash. If you must use a credit card, consider using a regular one instead — with terms and conditions you understand.