The state board has until Nov. 25 to certify election results.
No matter which side wins, the race was almost certain to be headed to a recount. Recounts are not automatic in Virginia but can be requested in contests decided by a margin of a half percent or less.
The margin on Tuesday was less than .01 percent.
The Democrat took the lead after the state elections board updated figures from Richmond, where Republicans sought a review of some heavily Democratic precincts and elections personnel on Monday tallied ballots from a voting machine that had not been counted.
The race has shifted back and forth in the week since Election Day, with the candidates at one point separated by just 17 votes out of 2.2 million ballots cast. The fluctuations occurred as officials accounted for a series of routine adjustments and simple human errors that changed the vote tally.