Williams (right) says Quins wanted to cover up the incident
The Rugby Football Union has not ruled out further action against Harlequins following the fake blood scam.
Quins were fined £259,000 and director of rugby Dean Richards banned for three years by European Rugby Cup (ERC).
The RFU opted not to investigate four other occasions Quins used fake blood but may consider sanctions in the wake of revelations from wing Tom Williams.
"They will be considered when we have received all the judgments," said RFU chief executive Francis Baron.
The RFU will await details of ERC's own appeal over the initial sanctions - when Richards, former Quins physio Steph Brennan and doctor Wendy Chapman had misconduct complaints dismissed - before deciding on any "next steps".
During the Heineken Cup quarter-final against Leinster at The Stoop on 12 April, Richards ordered Williams to feign injury by chewing a fake blood capsule to allow fly-half and goal-kicker Nick Evans to return to the field with five minutes remaining.
The board is satisfied that Harlequins have behaved properly in the interests of the club, player and other staff
Williams later had his lip cut in an attempt to make the injury appear genuine, and revealed full details of the incident and Quins' attempt to cover it up at an ERC appeal hearing into his initial one-year ban, subsequently reduced to four months.
The publication of the contents of Williams' testimony, released by ERC on Tuesday, were even more damaging for Richards and Quins chief executive Mark Evans.
Williams claimed he was pressurised by Richards, Evans and Quins chairman Charles Jillings not to give "full disclosure" about the incident.
The 26-year-old said he had been offered a new four-year contract plus other benefits by Evans and Jillings if he appealed solely against the length of his ban and did not implicate the club.
Williams also admitted he asked for his mortgage to be paid in return for agreeing to the demands.
Damaging though the testimony was, Quins issued a statement on Wednesday defending their conduct following last month's hearing.
"The board is satisfied that Harlequins have behaved properly in the interests of the club, player and other staff," it read.
"There are a number of matters with which the club would like to take issue but only one judgement out of five has been issued to date.
"Therefore it is felt to be wholly inappropriate to comment further until all the findings in all the cases have been published. At that stage, and not before, the club will make a full statement."
Richards resigned from his position at Quins on 8 August and admitted ordering the fake blood incident during a 14-hour independent committee meeting in Glasgow on 17 August.
The investigation into that incident uncovered evidence of four similar offences by Harlequins players in other matches - three times with fake blood gauzes and once, as with Williams, with a blood capsule.
The RFU's disciplinary chief Judge Jeff Blackett deemed that Richards and Brennan, who received a two-year ban, were responsible for the decisions and had already been punished over the Williams affair.
At that stage Blackett ruled that neither the players involved nor the club would suffer further sanctions, noting that the practice was not limited to Harlequins.
But after the Williams revelations were published on Tuesday, Blackett said: "Today's statement introduces new information into the equation which we were not aware of.
"The material we reviewed over the weekend related only to the additional four occasions on which fake blood was used.
"On these new allegations, difficult though it might be, we must have the full information before we decide on next steps."