Peter Bol's doping suspension has been lifted after his B-sample did not match his A-sample ©Getty Images

Commonwealth Games silver medallist Peter Bol's provisional suspension for doping has been lifted meaning he can return to competition with immediate effect, although Sport Integrity Australia (SIA) is still investigating the runner.

Bol, who finished as runner-up in the Birmingham 2022 men's 800 metres for Australia, returned a positive result for banned substance erythropoietin (EPO) last year.

His suspension, from a urine sample taken in October, was backdated to January 10 meaning he could not train or compete at any level.

He said he was cleared of doping allegations after his B-sample did not match his A-sample.

"Last month I told everyone that I was innocent and asked that everyone in Australia believed me and let the process play out," Bol wrote on Twitter, who was facing a potential four-year ban if found guilty.

"I was hopeful that the process would exonerate me.

"This morning, I am relieved to report that it did."

He cannot be too sure, however, as SIA later released a statement saying the case remains open despite the suspension being lifted.

SIA said the suspension was lifted after Bol's B-Sample produced an "atypical finding" which it states "is not the same as a negative test result".

The body will now seek for a World Anti-Doping Agency (WADA) accredited laboratory to obtain a second opinion from an expert on the WADA EPO Working Group.

EPO is classified as a non-specified substance under the World Anti-Doping Code and is prohibited at all times.

SIA has said that it is unable to provide a timeframe for its decision at this point.

Bol's lawyer, Paul Greene, said the way in which the tests results were handled was "unbelievable".

"The sun is shining for Peter Bol now," Greene told ABC Radio Perth.

"I told everyone he was innocent, and I turned out to be right.

"He had never taken this.

"There was something wrong with this test.

"And the fact that it was announced is a disgrace.

"He was never shown a lab document.

"He was told he was positive, it was announced and then … the B [sample] didn't confirm the A.

"It's unbelievable what happened.

Peter Bol won silver at the Birmingham 2022 Commonwealth Games but was facing a four-year ban if his samples matched ©Getty Images
Peter Bol won silver at the Birmingham 2022 Commonwealth Games but was facing a four-year ban if his samples matched ©Getty Images

"They should be embarrassed, the way this case was handled."

Greene claims that they were never shown any lab documents or supporting documentation and they never had an opportunity for an expert to look at the A-sample.

A similar case in 2003 saw double Olympic medallist Bernard Lagat, who has represented Kenya and the United States, threatened to sue what was then the International Association of Athletics Federations after he was alleged to have tested positive for EPO.

He was then cleared when a second urine sample tested negative.

Originally developed to treat kidney patients, EPO is known to be able to increase endurance.

It was used by American cyclist Lance Armstrong through the late 1990s and early 2000s during which he won seven consecutive Tour de France titles.

Belgian triathlete Rutger Beke was banned in 2002 for 18 months after a positive EPO test.

He was eventually able to clear his name after proving that his body was capable of producing EPO naturally which led to a false positive.