Ninety-five per cent of multiple sclerosis patients heading to a North Dakota screening clinic for MS vein therapy are from Manitoba, the clinic's owner says.

This week, Mobile Life Screening opened its doors in Fargo to MS patients for ultrasound tests that may determine if the controversial therapy could work for them.

The MS therapy is based on an unproven theory of chronic cerebrospinal venous insufficiency (CCSVI), put forward by Italian doctor Paolo Zamboni. It proposes that blocked veins in the neck or spine are to blame for multiple sclerosis. Zamboni treats MS by angioplasty — inflating small balloons in veins to open them up.

Some Canadians are spending thousands of dollars to seek the experimental treatment overseas.

Randy Spielvogel of Mobile Life said the clinic is booked solid, almost completely with Manitobans. It offers only screening for MS therapy to determine a patient's suitability, and not the therapy itself.

"There's obviously a demand for this CCSVI screening, and we're just filling that void," he said.

Some patients, however, have been met with a bill that's twice as large as they expected.

Spielvogel said that because he underestimated the amount of time the screening procedures take, he's had to raise costs to $800 from $400.

He said he didn't realize how time-consuming the tests would be when he first announced what they would cost months before the clinic opened.

"That we didn't realize … and that was our fault," Spielvogel said. "We shouldn't have opened our mouths, put the cart before the horse."