Two U.S. cardiovascular disease testing laboratories agreed to pay a combined fine of $48.5 million to settle allegations of paying kickbacks and conducting unnecessary lab tests. 

The U.S. Department of Justice said on Thursday that Health Diagnostics Laboratory (HDL) will pay $47 million and Singulex will pay $1.5 million to settle allegations of violating the False Claims Act. Both labs were accused of paying doctors up to $17 for every blood testing referral and for billing federal healthcare programs for unnecessary testings.

Based on the prosecutors' probe, HDL's conduct took place between November 2008 and January 2015, while Singulex's took place between January 2010 and October 2014. Both will be working wit the Department of Health and Human Services' Office of Inspector General to put up measures that will prevent the recurrence of such conduct, according to Reuters. 

HDL explained that the blood tests were necessary to properly rule out heart disease, Tech Times reported. The report also added that both laboratories earned hundreds of millions of dollars from the arrangement.

The violations involving HDL and Singulex were discovered after four private individuals came forward. These whistleblowers will be receiving proceeds from the fine, but the amounts are yet to be determined.

HDL and Singulex did not immediately respond to requests for comment on the court's decision.

The False Claims Act has recovered $23.9 billion since January 2009, with more than half of it related to fraudulent conducts and bills on federal heath care programs.