Thousands of years ago in Mesopotamia, doctors used to refer to prescribing and treatment guidelines etched on palm-sized clay tablets.

Today, according to Manhattan Research, almost half of US doctors use another kind of handheld device called a personal digital assistant, or PDA. What doctors do with these minicomputers would blow the minds of those ancient Mesopotamians—and even of their paper-dependent counterparts of 10 years ago. They look up information on thousands of drugs and then send a prescription electronically to the pharmacy. They calculate someone's risk of dying from a heart attack. They find the most authoritative research on treating a urinary tract infection. They correctly code their work to get paid as much as possible.

To be sure, PDAs like an HP iPAQ Pocket PC or a Palm Tungsten aren't good platforms for an electronic health record. Experts say their screens are too small for all the data you need to display. However, PDAs lend themselves perfectly to smaller chores, such as determining a medication dosage (drug reference is the leading healthcare application for PDAs, studies show). With wireless capability along with computing speed and memory that exceed that of 1980s-vintage desktops, PDAs handle data scut work better and better each year. Not surprisingly, they're getting to be as common as stethoscopes.

So what medical software should you load on your PDA? There are hundreds of good programs to choose from. To save you some research, we've compiled a list of 10 great programs in six major categories—drug reference, general medical reference, patient tracking, calculators, coding and charge capture, and e-prescribing. Maybe they wouldn't all make every doctor's top-10 list; but they're all very strong contenders.

In arriving at our choices, we received help from an expert panel of 10 primary care doctors from across the country. Not only do they use PDAs on the job, but many of them speak and write on the subject of mobile medical computing.

Our selection methodology was simple, and, admittedly, unscientific. We identified approximately 40 leading programs based on recommendations from dozens of doctors. We then asked our experts to winnow down the number to 10 and explain their choices. In most categories, a clear winner emerged. In the case of tie votes, we settled on a program that avoided duplication within a category, or worked on all PDAs.

That last distinction is important, because PDAs generally fall into two camps—those with a Palm operating system (OS), and Pocket PCs that rely on some kind of Windows OS from Microsoft. Its first OS for Pocket PCs, Windows CE, formed the basis for later ones like Pocket PC 2002 and most recently, Windows Mobile 5.0. While the PDA world is still bipolar, Windows may be poised for utter dominance in light of the recent announcement that Palm, a leading PDA vendor that no longer makes the Palm OS, has licensed Microsoft's Windows Mobile 5.0 for its Treo smartphones.

The 10 software programs we present won't break the bank. Many are free, and you can buy the remaining programs together for under $1,300 (prices are per year unless stated otherwise). Add a powerful PDA for between $200 and $400, and all of a sudden you're a digital doctor.

You've come a long way from clay.

Drug reference

Epocrates Rx
Source: Epocrates ( http://www2.epocrates.com)
Price: Free
Works with: Palm or Pocket PC (Windows) OS