But the appeals court reconsidered the case after a decision in June from the United States Supreme Court that prohibited prosecutors from introducing crime lab reports without testimony from the analysts who prepared them.

The appeals court reversed Ms. Lopez’s conviction, saying prosecutors had violated her constitutional right to confront witnesses against her by failing to put the analyst who prepared the blood-alcohol report on the stand.

But now, in an unusual move, the Supreme Court will hear arguments on Jan. 11 in a new case that raises questions about how lower courts may carry out its six-month-old precedent. Many state attorneys general and prosecutors are hoping the court will overrule its decision in the earlier case, Melendez-Diaz v. Massachusetts, before it can take root, saying it is a costly, disruptive and dangerous misstep.