The global anti-doping agency says it will decide by Saturday whether to strip Moscow's laboratory of the right to test athletes just months before the Sochi Winter Olympics.
Outgoing World Anti-Doping Agency (WADA) president John Fahey has the final say after receiving recommendations from a disciplinary committee.
"I assure you I will do that within the next 24 hours," he told journalists in Johannesburg.
"The disciplinary committee has met and considered the evidence that it has received," Fahey said at the World Conference on Doping in Sport.
WADA's board on Friday approved new, stringent rules against cheaters, which include a four-year ban for intentional first-time offenders.
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If Moscow loses its accreditation, it would not be able to test athletes' urine and blood samples for banned substances in the Winter Olympics in Sochi from February 7 to 23.
That would follow WADA's revocation of the Rio de Janeiro laboratory's rights to test in August, which will force organisers to fly samples to Switzerland during the football World Cup in Brazil.
Rio is also host city for the 2016 Summer Olympics, which means the host cities of both upcoming Games will potentially have lost testing accreditation - an embarrassment for the organising countries.
