Daryl Lease is an editorial writer at the Herald-Tribune in Sarasota, Fla. His e-mail address is daryl.lease@herald-trib.com.

Every month or so, I walk into the chain drug store around the corner from my house to get a prescription filled for my wife, daughter or myself. In many ways, it is a routine transaction, like mailing a bill or picking up a carton of milk.

The folks behind the pharmacy counter double-check my name and address in their computer files, ask if we have any allergies to medications and soon hand me a white paper bag containing the prescription. Usually, they remember to follow the store's instructions to ask me if I have any questions. I rarely do.

I usually think of it as a routine transaction -- one of 3 billion conducted at pharmacies around the country each year -- but it obviously has the potential to be more than that. If an incompetent or inattentive pharmacist gives us the wrong dosage or the wrong medicine entirely, someone in my family could fall seriously ill or even die.

More than a routine transaction

I try not to dwell on such things. I probably face greater odds of misfortune driving from my house to the corner. Besides, the pharmacists and staff have never given me reason to doubt their ability or diligence.

But they are human, and what they dispense is potent stuff. Only they know if the syrup they mixed or the pills they poured into the bottle match the prescription I brought to their counter. Our transactions are built on a web of trust -- or, more accurately, built around a margin of error.

According to state pharmacy boards, an estimated 2% to 5% of the prescriptions filled in the United States each year contain errors, ranging from simple, harmless mistakes like misspellings to much more serious and sometimes deadly errors. The National Association of Boards of Pharmacy estimates that 7,000 deaths annually are attributable to medication errors.

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The trouble is, all those numbers are largely guesswork. Although several industry groups ask pharmacists and others to voluntarily report medication errors, only two states -- Georgia and North Carolina -- require pharmacies to report mistakes. Even those reports are limited to instances where a customer dies or becomes seriously ill.

"Nobody's actually quantified this, which is a very big problem," Carmen Catizone, executive director of the National Association of Boards of Pharmacy, recently told The Washington Post. "That's really the first step. We're missing the key data to fix the system."

A deadly mistake

Five-year-old Brendan Ward is one customer who landed, tragically, in the margin of error. At bedtime one evening in April, his mother gave him two teaspoons of imipramine, a prescription she had filled at a pharmacy near their home in Virginia. By morning, Brendan was dead. A pharmacy technician mistakenly had upped the dosage fivefold, and the pharmacist had failed to notice.

The death of Ward, like others before him, has drawn considerable media attention and renewed worries, again, that too many of the nation's pharmacies are short-staffed, overworked and under-regulated.

Congress is focusing much-deserved attention on the cost of prescription drugs, but Ward's death and the alarms raised by Catizone and others make it clear the discussion should encompass a look at whether pharmacies are distributing those prescriptions safely.

Based on the estimated number of mistakes, it is evident that a more comprehensive system of recording errors is necessary so that regulators and pharmacies can detect patterns of trouble sooner and establish safeguards to prevent them. Industry groups have begun collecting data voluntarily, and those efforts should be expanded and the results shared with the public. Consumers would benefit from knowing if particular stores or chains have a poor safety record.

Many chain drug stores, including the one I frequent, have implemented a series of checks to make sure that what goes into those white paper bags is exactly what the doctor prescribed. Are some chains doing a better job than others? If so, could their safeguards be adapted to create a uniform, multiple-step system for all chains and independently owned pharmacies?

The costs of a heavy workload

Lawmakers and industry officials also need to address the growing shortage of pharmacists. The number of prescriptions filled annually -- 3 billion -- is twice what it was a decade ago, and is expected to mushroom to 4 billion within four years. But according to the Scripps Howard News Service, the number of pharmacists has increased by only 5% in the past 10 years. Currently, there are 7,000 jobs openings for pharmacists at national chains alone.

The increased workload has bred a fairly new occupation -- the pharmacy technician, whose training and expertise varies greatly from state to state. "There's a lot of non-trained people out there, and I suspect that the public would be terrified if they really knew," Douglas Scribner, president of the American Association of Pharmacy Technicians, recently told WebMD, an online health publication.

Scribner's group is pushing for national certification standards for technicians. The additional training might help lower the error rate. In 1998, the Virginia Board of Pharmacy surveyed close to 1,600 pharmacists, who said their technicians made an average of 6.5 prescription mistakes a week.

As the family of Brendan Ward can attest, none of us can take for granted what happens behind the pharmacy counter. Those transactions are not as routine as we may think.