The tax credit could be worth 20 to 25 per cent of taxable income, an accountant says. (iStock)

The controversial move by some Canadians with multiple sclerosis to receive an experimental treatment outside of the country could be heading to the tax office.

Some Canadians who've travelled out of the country for an unproven procedure proposed by Italian doctor Paolo Zamboni to treat narrowed or blocked veins in the neck say they'll submit a claim for medical costs on their income tax returns.

People might have to convince a tax assessor that the procedure meets the rules since the MS treatment is not approved in Canada, said Denis St-Pierre, a certified general accountant based in Bathurst, N.B.

"It makes it subject to interpretation," St-Pierre said from Ottawa on Tuesday. "As soon as you start interpreting the law, then it depends who's reading it."

St-Pierre thinks the expense would probably be tax-deductible, based in part from an interpretation or general view from Revenue Canada dating to 2008 on the subject of out of country medical claims for stem cell therapies.

But the Income Tax Act is one of the few Canadian laws structured with a reverse onus on claimants, St-Pierre said, and it will depend on whether the tax agency considers the vein angioplasty in MS patients to be a medical procedure.

The agency's interpretation states: "An individual's qualifying medical expenses are not restricted to those incurred or paid in Canada," so long as the hospital and medical practitioner are licensed where the procedure takes place.

If the person pays taxes, their medical claim could be worth 20 to 25 per cent of the actual amount paid, St-Pierre said. People who aren't taxable won't have any use for the credit, he added.

Toronto tax specialist Peter Weissman believes MS patients can boost their chances of success if they have a letter of support from a doctor. Weissman, who has MS, claimed a tax credit last year for an experimental stem cell treatment that is also not available in Canada.

"This is just for lack of a better term a no-brainer," said Weissman. "It's an allowable expense in the right circumstances."

Members of some MS advocacy groups are urging patients who've had surgery to submit expense claims.

Jessica Williams of Calgary, 28, went to Germany two months ago for the vein therapy to try to relieve fatigue, balance and strength problems, along with debilitating migraines, related to the relapsing MS she was diagnosed with eight years ago.

Her out-of-pocket costs totalled $22,000, which the Canadian health-care system won't pay. Based on her expenses, St-Pierre estimates she could be eligible for up to $4,000 in tax credits.

"My plan so far is I've got all the receipts put aside," said Williams. "I'm going to submit it to him [the accountant] and cross my fingers and hope that the CRA gives me a tax credit."

Williams says it is ironic that the tax branch of the federal government may recognize a treatment that health officials won't.