How long should you have to wait to see a doctor?

Fifteen minutes? Doesn't sound unreasonable to me, and one medical practice consultant says, "Research shows that an acceptable waiting time for patients is 15 minutes, 20 maximum, and if patients wait longer, they're really irritated."

Twenty minutes? Not much difference, I'd say.

Half an hour? This at least deserves a polite explanation. A lot of things can keep a doctor unavoidably busy.

Anything longer? This deserves an apology, though not necessarily an abject one, since the doctor may have been trying to save a life or deal with a sudden crisis.

Could the reason be less noble, however? A long chat on the phone between doctor and spouse? Socializing with fellow docs over coffee? Or keeping a habitually sloppy schedule?

All these things happen, say doctors themselves and experts in the management of medical practice.

Perhaps the first thing to say on the subject is: Don't judge a doctor by your waiting time alone. Habitual tardiness may indeed be a sign of slipshod ways generally. But it may not.

I've known some fine doctors who were simply so caring and patient with patients that they ran later and later as their day progressed. Their good qualities made up for their tardiness.

If you have that kind of physician, relax and bring a good book or magazine to read while you wait.

If the situation is otherwise, you're entitled to blow up.

Many doctors admit this. In a recent interview, a Medical Society of the District of Columbia committee head told of one patient's letter to the society. The patient had waited an hour and three quarters to see his doctor. Neither doctor nor staff gave any explanation. The doctor took only a brief look at the patient and sent him off for an X-ray.

The patient waited for the X-ray, then -- again for too long -- for his doctor to report the results. The doctor finally saw him "for three minutes," the angry patient reported, and gave him an explanation he didn't understand.

"I sympathize," the medical society doctor said. "I happen to have seen the same physician."

Such stories abound. A government survey found that in 1977 the average patient spent "about 30 minutes" waiting for the doctor. This means large numbers of patients waited longer.

Some doctors commonly overschedule, betting some patients won't show up. Some overuse what they call a "wave schedule," scurrying from examining room to examining room to try to handle several patients at a time. Some just have more patients than they can handle and, in one doctor's words, "make the tacit assumption that their time is more valuable than yours."

Yet the patient may be taking time off from work, without pay. There may be children left at home, unattended. The patient may have other commitments.

Last July, Jean Lawrence, a Washington businesswoman, wrote an incensed article for this newspaper's Outlook section, saying: "You have a right not to wait more than 15 minutes in the doctor's office," since "Doctors are vendors. They are selling a service. And some have a better service to sell than others. It's that simple."

But it is not. "I try to respect my patients' time as much as they respect mine," said Dr. Barry Lubin of Norfolk, "but physicians are always getting backed up."

"Emergencies happen," said Dr. Murray Paul, a Silver Spring and Gaithersburg pediatrician. "They don't happen every day. But yesterday my two associates and I had to drop everything and give a severely asthmatic boy multiple adrenalin injections, then arrange for a properly equipped ambulance to take him to the hospital.

"I might see a child with a 105.5 fever and spend an hour and a half with a nurse sponging him to bring the fever down.

"Most of our patients understand. We try to run a fairly efficient office and leave openings for the unexpected. But you can't be a mind reader.

"Once in a while a patient gets really incensed about waiting. But it might have been their child with the 105 fever."

Medical societies and medical practice mangers, including American Medical Association consultants, advise doctors:

* Acknowledge patients immediately on arrival.

* Let them know if there will be any delay. If it will be lengthy, offer them a chance to come back later or reschedule.

* If within easy walk of a shopping area, give patients a beeper and let them leave for a while.

* Give patients interesting reading material, including pamphlets about current medical problems.

* Don't put patients in an examining room until you're nearly ready for them.

* If you habitually make patients wait, reexamine your daily schedule and leave some slots for the unforeseen.

Writing in Family Practice News (and other doctors' newspapers published by the International Medical News Group), practice consultant Duane M. Johnson told doctors: "Patients expect a brief wait . . . and they understand that delays are sometimes unavoidable. But they also expect courtesy, consideration and respect for their time.

"Excessive waiting time . . . will eventually tear down whatever good patient relations you have built. Patients will simply go elsewhere, and you will have plenty of time."

I happened to visit Beth Israel Hospital in Boston recently.

A patient was waiting for a doctor outside an examining room. When the doctor came out to get the patient, he was friendly and smiling and he said, "Hello, Mrs. A., I'm Dr. B. Thank you for waiting."

The incident seemed just unusual enough to remember, almost as vividly as we remember the times we feel we've waited too long -- or forever.