More than 30 people were charged this week in a massive alleged Medicare fraud scheme that investigators say cost taxpayers as much as $2 billion.

The Associated Press reported Friday that a joint operation between the FBI, Department of Health and Human Services (HHS) and U.S. attorneys' offices resulted in charges for dozens of people accused of participating in a scheme to dupe seniors into taking unneeded DNA tests.

According to the report, the scheme centered around convincing victims into taking genetic tests to determine their risk factors for various diseases, including for cancer, which is not routinely tested through genetic means.

The scheme allowed participants in the fraud to acquire patients' Medicare ID and use it for future illicit purposes, according to the AP. Multiple entities and labs were involved with the scheme, prosecutors allege, and Medicare reportedly paid out hundreds of millions of dollars for unnecessary medical tests before the fraud was discovered.

"A decade ago, it would have given Medicare beneficiaries pause if someone wanted to get a swab from their cheek of their saliva," Shimon Richmond, head of the HHS inspector general's investigation unit.

"Today people know and recognize what [genetic testing] is, and they think 'I can get that done, and I can get it done for free and find out if I have health issues that I need to address,' " he added.

Officials advise patients worried about falling victim to Medicare fraud to only participate in medical operations recommended by their primary doctors.