Coasters that can detect date rape drugs in a drink sound almost too good to be true to many young women.

And recent tests and criticisms from various groups, including the Michigan State Police, might have proven the inefficiency of the invention.

The coasters, released in late winter, are sold by Florida-based Drink Safe Technologies, Inc. and can be bought at convenience stores. They also have been distributed by college campuses and YWCAs.

“Certainly we would want to advocate for the safety and well-being of women if there was something we could promote that was tested and proven,” said Beverly Chisholm, president of the Greater Lansing YWCA. “But I would be reluctant to throw support behind something I just don’t know much about.”

Chisholm said she’s never heard of the coasters and would be wary before distributing them to women in this area. Women using the coasters might have a false sense of safety in a potentially dangerous situation, Chisholm said.

Scientists at the Michigan State Police Crime Lab said the coasters did not clearly identify date rape drugs during testing and worry about women’s false sense of security.

Only two drugs are identifiable by the coasters - gamma hydroxybutyrate, or GHB, and ketamine. There are at least 36 drugs that are classified as date rape drugs.

The coasters are supposed to turn a dark blue from the light color they normally are, but the lab’s forensic scientists say it was difficult to see the discoloration. The lab tested the coasters with red wine, cola, whiskey and orange juice.

About 50 million coasters have been sold since March. The company, whose president is a former magician, also produces fake snow and party foam and says the coasters are accurate 95 percent of the time. The company’s president, Francisco Guerra, said he has been thanked by various women who say the coasters have saved their lives and says while they may not always be accurate, it’s a step in the right direction.

Sara Teller, an English and general management sophomore, said she would buy one of the coasters.

“There aren’t too many things that could detect those drugs,” she said. “Even if it only works half of the time, it’s better than nothing and could be worthwhile until they come up with something more accurate.”

Other groups that want people to be skeptical of the coasters include the prevention organization Project GHB and the Drug Enforcement Administration.

The Associated Press contributed to this report.