Despite the booming business, Wood and his staff - another doctor and four physician assistants - have battled strong head winds to keep the clinic going. Rising administrative costs and flat insurance-reimbursement rates make it tough to cover basic expenses. One in five patients lack insurance; others are saddled with sky-high deductibles. Last year, Wood even cut his annual salary by half to help keep the clinic afloat.

In an attempt to turn the tide, Wood is trying a new approach - one that he hopes will one day sustain his practice.

For a monthly fee of $83 per individual or $125 for a family, the clinic provides unlimited primary and urgent care. Those who enroll in the prepaid plan get office visits, lab work, X-rays and as many generic drugs as the clinic can provide.

Wood is one of several hundred doctors across the country offering flat-rate, pay-in-advance plans. Though still experimental, proponents argue that the approach tackles two crises in U.S. health care - the rapid decline of doctors practicing primary-care medicine and the growing number of Americans who are either uninsured or underinsured.

''I can't see my practice surviving for the next 10 years without this model.'' says Wood, who has enrolled 100 people in his plan. The streamlined system cuts down on administrative hassles and costs, compels more office visits - and delivers better profits than one that relies on insurance dollars.

Prepaid plans - and the opposition they face from various industry and regulatory factions - show how the medical establishment remains at odds over the delivery of basic care. Insurers say that high medical and drug fees force them to police doctors' treatments and rates. Physicians argue that the hassles of processing insurance claims and referrals means less time with patients. At the conflict's root, say health experts, is a medical payment system that tends to reward expensive, procedure-based care over routine, family-doctor visits.

Family physicians and internists have seen their incomes shrink 10 percent because of flat or falling reimbursements. Over the past decade, their ranks have fallen dramatically and the number of medical students who are going into the discipline has declined by half, according to the American Academy of Family Physicians.

A recent study in the British Medical Journal said that the average American logs barely 30 minutes a year with a primary-care physician - half the time spent in other developed nations. That helps explain why the U.S. spends much more on health care than its economic peers, yet still falls behind on basic indicators such as life expectancy and infant-mortality rates.

Prepaid plans aren't intended to replace more comprehensive coverage. Rather, physicians such as Wood see them as filling an important gap in primary care. His main targets are individual patients with basic medical needs and employers who want to supplement costly, high-deductible plans.

Unlike traditional insurance, which is priced to spread the risk of high-cost illnesses such as cancer across many people, prepaid care is more like a gym membership - giving people medical access for a fixed cost.

To determine his fees, Wood says he estimated that the average adult would need about 20 itemized services a year - from blood tests to X-rays. He leveraged his good relationship with the Ohio Valley Medical Center to get lab work performed at low Medicare rates. He also put together a list of 100 generic drugs that he could buy directly from wholesalers.

Prepaid plans have raised concerns among insurers and some regulators that patients might forgo broader health coverage - or get ripped off. If the approach took off, it might become a competitive threat to insurers' business, especially if doctors can provide prepaid care without having to jump the same regulatory hoops as health insurance.

Wood has found an ally for his plan in Gov. Joe Manchin, whom he cornered at an election fund-raiser in 2004. Intrigued, the governor appointed him to a task force charged with tackling the state's uninsured problem. After more than half a year of meetings, the task force called for a three-year experiment with prepaid care as part of a legislative package.

Wood says he hopes most patients and local employers who sign up for prepaid care can use it to supplement a catastrophic, or high-deductible, plan. Some local business owners say they've saved big by taking the prepaid route.

Wood says he's signing up new prepaid patients at a rate of about a dozen a month. He projects that 1,200 enrollees would be enough to support the clinic.

''I'm going to take this as far as I can,'' he says. ''Primary care is the one area of health care that every patient needs to participate in - and this is the way to do it.''