Claressa Shields Says She's Working W/ Boxing Commissions To Fix Drug Testing

Claressa Shields is determined to prevent other boxers from experiencing the hell she went through with her recent false-positive drug test ... telling TMZ Sports she's working with boxing commissions to improve the entire process.

The undefeated boxing champ was suspended from competing in Michigan shortly after her fight with Danielle Perkins in February for allegedly testing positive for marijuana -- something she claims she's never put in her body.

The Michigan Commission later lifted the suspension "following receipt of additional evidence that a procedural error occurred during the collection of Respondent’s oral fluid specimen."

Now, Shields is urging for changes to the testing process -- including within the Michigan Department of Licensing and Regulatory Affairs.

"I'll be working with the Michigan Commission and other commissions to make sure the right steps are taken like when a fighter does test positive for anything," Shields told us at LAX.

The 16-0 heavyweight called the drug testing error and the way the commission handled it as harmful to her reputation and career. Therefore, she and her team will fight for a resolution.

She also criticized media outlets for quickly reporting false news ... while neglecting her in-ring accomplishments.

Despite the mix-up, Shields is living like a champ ... and celebrated her 30th birthday with her friends and boyfriend, rapper Papoose.

"I always knew I was Lucky," Shields said on her birthday. "Who wins the Olympics at 17 years old, then do it again at 21? Who Wins 17 World Titles and wins 4 Undisputed Championships?!"