ST. LUCIE COUNTY — A chain of urgent-care centers is offering a medical membership plan that could give uninsured families a cheaper way to get regular care.

The medical membership plan at Physicians Immediate Care works like a season pass at a theme park. You pay the membership fee — $206 a month for a family of four — and then pay only $20 a visit for most medical care provided at any of Physicians Immediate Care’s locations.

The business’ fourth center opens May 1.

Like a theme park pass, the medical plan makes financial sense if you expect to visit often. People who buy the plan are betting paying the monthly fee, which is deducted automatically from their bank account, plus visit payments, will be cheaper than paying a la carte for services.

A visit and treatment for strep throat usually costs about $120. Physicians Immediate Care handled more than 36,000 visits last year, and at least one family — with three active boys — had a spurt of weekly visits, owner Dr. Kenneth Palestrant said.

But because not everyone who buys a medical membership will need such frequent visits, Palestrant said the plan makes good business sense, too. Urgent-care centers around the country, including in Missouri and Colorado, have implemented similar discount plans successfully.

“We’re not going to get rich off this,” Palestrant said. “We will make some profit, depending on how many people come in ... but we’re doing it more so because it’s good for the community.”

Palestrant’s centers are among the dozens of urgent-care centers that have opened on the Treasure Coast since 2005.

Across the country, an increasing number of urgent-care centers — the urgent care association counts 8,700 nationwide, nearly twice as many as there are hospital emergency rooms — are filling a need for routine, immediate care caused by a shortage of primary care doctors and an increase in uninsured patients. Proponents say the centers are less expensive and more efficient than emergency departments and meet the medical needs of uninsured people who earn too much to get free or reduced-rate care from health departments or community clinics, but too little to buy insurance on their own.

The medical membership plan appears to be unique on the Treasure Coast, though other local urgent-care centers have experimented with ways to make payment more convenient. Treating patients as customers who must check their budgets when considering care is a common characteristic of urgent-care centers. Solantic, a Florida chain with centers on the Treasure Coast, provides a pricing list on its website and introduced a prepay card.

Critics of urgent care centers, including the American Academy of Pediatrics, say they do not provide comprehensive care because all appointments are on a walk-in basis and people just see whatever doctor or nurse practitioner is on duty.

But some care is better than no care at all, according to urgent care advocates, including the American Academy of Urgent Care Medicine, an arm of the American Medical Association.

Regular, budget-friendly treatment at an urgent-care center also is better than getting a big bill from the emergency department or because you waited too long for care and a small, easily fixed problem became a large one, said Palestrant, who was the medical director at the St. Lucie Medical Center emergency department for 10 years.

Palestrant expects most of the customers who buy the medical membership plans to be “working class families.” Small businesses who can’t afford to provide insurance for their employees also might consider the membership plans as an alternative benefit, Palestrant said.

PHYSICIANS IMMEDIATE CARE LOCATIONS

1900 S.E. Port Saint Lucie Blvd., Port St. Lucie: (772) 398-1588

4007 S.W. Port St. Lucie Blvd., Port St. Lucie: (772) 343-1774

5550 S. U.S. 1, Ft. Pierce: (772) 460-9227

1730 S.W. St. Lucie West Blvd., Port St. Lucie: (772) 873-8155

Open 9 a.m. to 7 p.m. Monday through Friday; 9 a.m. to 5 p.m. Saturday and Sunday

MEDICAL MEMBERSHIP PLAN DETAILS

Physicians Immediate Care owner Dr. Kenneth Palestrant said the membership plan could save money for uninsured people in need of frequent medical care.

Monthly cost: $59, additional family members are $49 each

Per-vist fee: $20

Services included in plan costs: general medical care, X-rays, physicals, lab draws, splinting for sprains, sports medicine and treatment of minor injuries, cuts and wounds

Extra-cost services: immunizations, blood tests, ultrasounds, Workers’ Compensation Injuries

Blood testing is available for $15. Some generic medications are available for $10 to $30 per prescription.

For more information, visit www.immedcare.com.