LANSING — Attorney General Dana Nessel has sought court approval to investigate Eli Lilly and Co., accusing it of charging excessive prices for insulin.

The filings asked an Ingham County judge to authorize a probe under the state consumer protection law, including the use of subpoenas to get records and to interview company officials. The petitions also requested a judgment saying exceptions to the law do not apply in this case.

“The average out-of-pocket cost of a single vial of insulin is nearly $100,” Nessel said. “No Michigander should have to face that kind of cost for life-saving medicine.”

Nessel also said that if the investigation is not allowed her department will appeal that decision. The filings said that the 1999 and 2007 high court decisions were wrongly decided and “have served to end many consumer cases and have prevented countless others from ever beginning.”

The American Diabetes Association estimates that nearly 865,000 Michiganders, 11 percent of the adult population, have been diagnosed with diabetes and more than one in five people nationally depend on insulin.

Prices for insulin can range from $75 to $2,000 monthly depending on dosage and insurance coverage. According to researchers at the Rand Corp., U.S. prices are more than eight times higher than in 32 high-income comparison countries combined.