The likelihood your primary care doctor refers you to a specialist is increasing, but how your physician may hear about that specialist may surprise you. It's often not from medical journals.

Sabrina Alexander spends most days visiting different physicians armed with brochures and head shots touting the qualifications of the doctors in the orthopedic group where she works.

"The things that I can do really help my specialists shine to other primary care physicians and help them stand out against our competition," said Alexander.

She's part of a growing industry of "client liaisons." Specialist physicians hire these go-betweens to let primary doctors know their expertise is available.

"Oftentimes that is the only way that we learn about a new doctor in town," said pediatrician Dr. Matthew Cepeda.

That's because health care has changed over the last decade. A study found the number of patients referred to specialists nearly doubled. Busy primary care docs booked solid with patients don't spend as much time in the hospital meeting other specialists. So Dr. Cepeda is happy to meet with specialists' representatives.

"Whenever I need another resource they're the best way for me to find out what else can be done for your health care," said Cepeda.

But critics worry these office-to-office pitches could pose an ethical health hazard.

"I don't think patients have the vaguest idea that their referral might have been the result of a marketing campaign," said bioethicist Lawrence Nelson.

Nelson hopes primary care docs are basing referrals only on specialists' qualifications.

"The best protection for patients is physicians who are following their ethical obligation to make referrals based upon the patients' need and personal preferences and not on slick marketing," said Nelson.

Sabrina Alexander points out that if a patient is steered the wrong way, it affects the doctors too.

"The primary care physician's reputation is also on the line," said Alexander. "So they have to be comfortable with the specialists that they're referring their patient to."

Experts say patients should always ask any specialist they're referred to basic questions like: "Have you seen problems like mine before?" "How many patients have you treated with this condition?" And "What were the outcomes?"