At least a dozen drunken driving cases pending in the Edgartown district court are on hold as a case about breath test accuracy works its way through the state court system.

A decision could come soon on a lawsuit with more than 600 defendants that takes up the reliability of breath test devices used by police, with defense attorneys arguing that the devices are not reliable and should not be used as evidence in drunken driving cases. The case is being tried before the Hon. Robert A. Brennan, a district court judge in Concord. A hearing in the case ended last week.

More than 1,500 cases in the commonwealth are unresolved pending the outcome of the litigation, according to court documents. Edgartown district court clerk-magistrate Liza H. Williamson said 12 cases are on hold in the court here.

The case centers on the technical workings and scientific reliability of the Draeger Alcotest 9510, a breath testing device used by Massachusetts police in drunken driving cases. Breath testing devices used by Massachusetts law enforcement are under jurisdiction of the Office Alcohol Testing, a division of the state police. Judges have ordered the state to provide Alcotest 9510 instruments and source code available to the defense for testing, according to court documents.

Lawyers representing drunken driving defendants are seeking to have breath device results from the Alcotest 9510 excluded from any trial and deemed inadmissible and unreliable in court. The case involves technical details about breath test device settings, among other things. Two separate proceedings, one in Boston Municipal Court and the other in Concord district court, were consolidated last year in regards to the breath test reliability issue.

Meanwhile stays have been issued for other cases that might be affected by the outcome, including the cases at the district court here. Stays suspend time guidelines required for a speedy trial.

Cape and Islands district attorney Michael O'Keefe said Friday that his office only has a handful of cases involved that have been stayed pending the court decision, and a previous case about breath test accuracy had been decided in favor of the commonwealth.

“We'll see what the court does and we'll act accordingly,” he said.

Edgartown attorney Robert Moriarty, who represents six defendants with cases on hold pending the court case, said the case is important in light of the role breath devices play in drunken driving cases. Mr. Moriarty said cases that have been stayed involve drunken driving charges in which a jury could find reasonable doubt without a breath test result.

“That’s not to say that the commonwealth does not have a very legitimate interest in protecting its citizens,” he said. “That is totally true. People should not do this, drive if they’ve had too much to drink. But at the same time people should not be convicted on speculative science either, and science that has not been fully vetted.”

A so-called Daubert-Lanigan hearing, which explored the science behind the breath test, ended Feb. 3. A judge may hold a Daubert-Lanigan hearing as part of a court case to consider whether scientific evidence and expert witness testimony about it is reliable. The name comes from two Massachusetts court decisions that set standards for judging evidence said to be based on science.

In a document filed in court in January, representatives for the commonwealth asked the court to deny the request, arguing that the Alcotest is reliable and uses well-established technology that is not new or untested technology. The commonwealth also said the issues discussed should help determine how breath tests are weighed in cases, not whether they are admissible.

Lowell attorney Gregory Oberhauser, one of the defense lawyers in the case, said Thursday the hearing was supposed to take four days and ended up running more than two weeks.

“The top court found that the machine itself is new and the science behind it needed to be explored,” he said, adding that the hearing allowed the defense team to look at and test the breath test devices and look at Office of Alcohol Testing policy.

The judge said he aimed to have a ruling by March 1, Mr. Oberhauser said, and appeals are possible on either side. Mr. Oberhauser said there is a chance the Supreme Judicial Court could take the case to make parts of the ruling final so cases can proceed.

Concerns about the breath devices date back several years. In April 2015 questions about testing prompted a review by the state Executive Office of Safety and Security, and several district attorneys, including Mr. O’Keefe, temporarily suspended using breath testing devices as evidence in court cases. The review of breath test records found no basis to doubt the reliability or accuracy of the Draeger 9510 devices, according to a letter from the office, but found two types of operator error that could affect outcomes. Six relevant cases on the Cape and Islands were dealt with, Mr. O’Keefe said in a press release at the time, and he lifted the embargo on using breath test results after a few weeks.