Fraudulent billing is the most common healthcare fraud scheme, making up about 68% of all resolved cases, per the Government Accountability Office.

In a report released Monday, the GAO reviewed 739 healthcare fraud cases resolved in 2010. Of those cases, about 43% were related to billing for services that were not provided. Another 25% of cases involved providers billing for services that were not medically necessary.

Other common schemes include falsifying records at 25% of resolved cases, paying kickbacks at 21% and fraudulently obtaining controlled substances or misbranding prescription drugs also at 21%.

Providers were complicit in 62% of the cases, while beneficiaries were complicit in 14%, the report said.

For cases where individuals billed the government or private health insurance companies using a beneficiary or provider’s information without their knowledge, the GAO suggests “smart card” technology that verifies that both the provider and beneficiary’s approval of the billing. Smart cards could have potentially prevented around 22% of the cases reviewed, GAO said. However, they would not have made a difference in cases where the provider misrepresented their services.