The answer to question 1 is, only if you proceed very carefully and follow the guidelines listed below. The answer to question 2 is, Yes, you could be held liable. Once medical advice is proffered-whether in the office, over the phone, or in a friend's dining room, a doctor-patient relationship is established, as is a duty of care. That duty is what makes you a potential defendant.
The second element in a malpractice case is departure from the standard of care, which requires you to act as a "reasonable physician in your specialty." The standard of care rule applies whether the advice is formal or informal, and whether or not you charge a fee. (Standard of care criteria are less stringent if you're acting as a Good Samaritan. But even then you have to be careful not to leave the patient in worse condition than you found him.)
To bill or not to bill? That's up to you. If you want to waive payment as a gesture of friendship, fine. But most patients who are covered by health plans will be happy to give you their insurance information.
If you're not comfortable with the idea of treating acquaintances or friends due to social, financial, liability, and other considerations, you might consider drafting an office policy that all people whom you know socially must be treated by other members of your group. Solo practitioners can tell informal advice seekers that they'll be glad to recommend physicians in the community. This is especially wise if the query is outside your area of specialization.
The author, who can be contacted at email@example.com, is a healthcare attorney in Mt. Kisco, NY, specializing in risk management issues.
This department deals with questions on common professional liability issues. We cannot, however, offer specific legal advice. If you have a general question or a topic you'd like to see covered here, please send it to Malpractice Consult, Medical Economics, 123 Tice Blvd., Suite 300, Woodcliff Lake, NJ 07677-7664. You may also fax your question to us at 201-690-5420 or e-mail it to firstname.lastname@example.org