You've heard of the medical home? Well, we're here to tell you about what you might consider the medical mobile home.

And it's a mobile home with data!

The Family Van, Harvard Medical School's Winnebago-sized mobile clinic, offers free tests and counseling to medically underserved patients in Boston. Most of them do not have their own doctor, and instead head straight to the emergency room when they get sick.

A study published this week in BMC Medicine found that the van program saved the health care system more than $20 million in 2008 alone. The data, using what one expert called an unusually straightforward approach, is welcome because it's useful to get good solid numbers on  preventive care and cost savings.

The Boston Globe writes:

As US healthcare costs spiral upward and lawmakers debate ways to overhaul the system, a team of Harvard-led researchers suggests that such alternative approaches are an overlooked but valuable return on investment. Using a formula they developed, the researchers figure that The Family Van returns $36 for every $1 invested.

The researchers’ formula, which they plan to fine-tune and release publicly later this year, takes into account the savings from providing services in the van—one visit costs Harvard around $117, for an annual cost of $566,000—rather than in the emergency room, where treating a nonemergency illness can run upwards of $920. The study found that those savings from van services alone totaled $3.1 million.

But the researchers went a step further and quantified the savings in “life years,” a concept used to measure the value of health treatments in terms of years added to patients’ lives. According to the researchers, the van’s medical interventions saved 254 quality years of life for its patients. With each year of life valued at $70,000, those savings add up to over $17.7 million.

Put everything together and you get a remarkable $20.3 million in savings. Said Paul Cote, one of the study’s coauthors: "You get a much bigger bang for your buck with these simple preventions.”