I'm no public opinion pollster, but I do have a rule of thumb. One phone call in a week about a subject makes it "of interest." Two calls make it "a possible trend." Three make it "a definite trend." Four make it a "surge."

It has been surging lately -- about one of the oldest, falsest stories ever to do the rounds. Maybe you've heard it yourself: the one about how you can collect empty cigarette packs and trade them in so that a kidney patient can receive free time on a dialysis machine.

It is not true, people.

It is not about to become true.

According to kidney patients and officials of kidney treatment organizations, it never has been true.

The only thing that's true is that I have been getting some pretty way-out calls about the cigarette trade-in tale -- and so have some other Washingtonians.

One guy called me last week to ask where to send the packs. I informed him that "packs for dialysis" was only a bad rumor. "Well," he said, in the height of huffiness, "I guess I couldn't expect anything better from an ex-smoker." And he hung up.

The next caller, a woman, said she had two foot lockers full of Lucky Strike packs. I advised her to throw them in the trash. "Oh, I couldn't do that," she told me. "Kidney disease runs in my family, and you just never know when you might need them." This right after I had told her the packs were worthless!

Even the D.C. Lung Association, which isn't exactly pro-smoking, is getting "dialysis calls." Marisa Sandifer, DCLA's director of communications, says she got one not long ago from a woman in Prince George's County. "I suggested that the best way for anyone to help anyone is to get off cigarettes, not to save empties," Marisa says. No argument with that.

Let's do unto the dialysis rumors what savers of cigarettes packs should do with their hoards. Bury them once and for all.

She asked to remain anonymous because her son has to go there every day, says the woman from Silver Spring. That seemed reasonable. But the same can hardly be said for what the woman mailed in along with her letter.

It's "Parent Bulletin No. 3," issued early this month by Kemp Mill Elementary School. At the bottom of the first page, it reports that the "standard grading policy requires that the teacher conference with the parent(s) regarding their child's progress."

My correspondent and I both wonder: whatever happened to "confer?"

Take a good look at the size of this column. You won't see another one this small until the latter stages of January. The reason? Children's Hospital.

Beginning Monday, this column undertakes its annual holiday-season fund-raising drive on behalf of the Hospital on the Hill. For the next eight weeks, you will get almost twice as much Bob Levey's Washington for your money, as we beat the drums on behalf of the kids and list the names of groups and organizations that give.

I'm sure a lot of you are taking today off to recover from yesterday's calories, or because the family decided to stay in town and make it a four-day weekend. That means you have the time and the opportunity to pick up your checkbook and become an early-bird donor to the 1982-3 campaign. I invite you to do so -- and to do so today.

Why the hurry? Because we are making a special effort this year to raise as much money as possible as early as possible. If we do, the hospital can make a few extra bucks in interest. More important, it can be sure of having enough money to keep some endangered programs alive.

If you give today, you help the hospital accomplish both purposes. Thanks very much in advance.

To contribute to the campaign:

Make your check or money order payable to Children's Hospital (no cash, please) and mail it to Bob Levey, The Washington Post, Washington, D.C., 20071.