The latest Bloomberg Businessweek devotes six pages to concierge medicine, a concept that treats health care like most other market-based services.

Atlas MD isn’t a free clinic. It’s a concierge medical practice, which means you can’t get an appointment unless you pay cash. Atlas MD’s two physicians, Josh Umbehr and Doug Nunamaker, don’t accept insurance. Instead, they charge most of their adult patients $50 a month for unlimited visits. They also offer free EKGs and biopsies and cut-rate prices on prescription drugs. Two-thirds of their patients have insurance but feel the fee is well worth it for personalized service, including house calls, the doctor’s cell-phone number, and quick responses to e-mails and Twitter messages. The rest of Umbehr and Nunamaker’s clientele are uninsured. For those patients, Atlas is the only way of seeing a family doctor regularly. Contrary to those who say concierge doctors like themselves are getting rich by focusing on personalized care at a high price, Nunamaker and Umbehr, who are in their early 30s, contend that they can grow their practice by appealing to a broader clientele.

“I want to be one of the 1 percent,” says Umbehr, who likes to talk business as much as he does medicine; Ayn Rand’s Atlas Shrugged inspired the name of his two-year-old practice. “But the problem with the 1 percent is there’s only 1 percent of them. If you want to build a business model that’s really far-reaching and world-changing, then it’s got to fit everybody.”

It was midway through the month when the homeless woman arrived at Atlas MD, so Nunamaker asked her for $25 and examined her immediately. She told him she was always tired and couldn’t keep a job. She was living in a storage shed. Nunamaker gave her a blood test, which revealed an extreme case of hypothyroidism. That explained her exhaustion. “I get why you are so fatigued,” he said. “Your thyroid isn’t working as well as it should.” He put her on medication that would boost the hormone her thyroid gland wasn’t producing and restore her vitality.

The woman stayed with Atlas MD for three months until she was feeling better. Then she left. Nunamaker gave her three months of inexpensive prescription refills and wished her well. He would have preferred to see her stay on. But he and Umbehr are proud that they were able to restore her health for $147, including tests and prescriptions. (They made money on her monthly retainer, but not on the tests and labs. Atlas MD provides them at cost.) They estimate that she would have paid as much as $1,500 if she had gone to a regular doctor.