WASHINGTON – In his ads and on his campaign site as the Democratic nominee in Michigan’s 6th Congressional District, Matt Longjohn refers to himself as an “M.D.”

But is he a medical doctor?

According to an article published Wednesday by the Michigan Information & Research Service (MIRS), Longjohn isn’t licensed in Michigan or in his former home state, Illinois, as a medical doctor, though he earned a medical degree at Tulane University and did his residency at Northwestern University.

It may not make any difference politically speaking, since Longjohn — who is running against U.S. Rep. Fred Upton, R-St. Joseph, in the southwestern Michigan district — isn’t offering his services to patients as a physician and has mostly worked as a health researcher and administrator on health projects.

But the MIRS story says there could be some legal questions, since Michigan’s Public Health Code says a person can’t use a designation that could “induce the belief” that a person is “lawfully entitled in this state to engage in the practice of a health profession.”

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Longjohn’s campaign noted that graduates of four-year medical schools in the U.S. earn a "Doctor of Medicine" or M.D., regardless of whether they are licensed in a particular state or not. Longjohn also told MIRS that he has “never once said during this campaign that I am a currently practicing physician."

Unsurprisingly, the state Republican Party chastised Longjohn for calling himself an M.D.

“If Longjohn is willing to misrepresent himself about this, where does he draw the line?” said Sarah Anderson, the state party’s deputy chief of staff. “Southwestern Michigan deserves to be represented by a leader who tells the truth. Not someone who is willing to say anything in order to win an election.”

Longjohn's campaign called the Republican remarks a "ridiculous smear."

"This ... shows just how desperate 32-year incumbent Congressman Fred Upton and the Michigan Republican Party are to keep Fred in his seat," the campaign said.

Contact Todd Spangler: 703-854-8947 or tspangler@freepress.com. Follow him on Twitter at @tsspaangler.