A recent Maryland Court of Appeals decision has made it easier for prosecutors to obtain convictions after serious drunk driving accidents, say attorneys. For the first time, blood test results obtained by doctors while treating injured drivers, and which indicate intoxication, can be used as evidence in court.

Until now, such tests could not be used unless the person charged was advised that he could choose between breathalizer and blood tests, and have the test administered by his own physician. But in many cases, according to the state's attorney's office, police have no indication a person had been drinking until they learn of test results.

The decision is helpful to prosecutors only when the drunk driver is taken to a hospital for medical treatment, but, in a state where police believe that 60 percent of last year's 772 fatal road accidents were alcohol-related, it will have "significant impact," according to Maureen Gardner, a state's attorney who has overseen many drunk-driving prosecutions.

The decision, published Oct. 14, ruled that blood samples taken for medical purposes from Carroll County resident Craig Wesley Moon could be used against him. It came one day after another Court of Appeals decision, seen as a defeat by the state's attorney's office, that blood sample results could not be used in cases where police suspected drunk driving, but failed to advise the injured driver of his choices.

Although it is impossible to measure the results of the decision in numbers of convictions, the course of at least three Maryland cases involving drunk driving charges and fatal accidents has been altered by it.

One of the first men affected by the Moon decision was Clayton E. Lawrence, a Montgomery County man charged and convicted of manslaughter after a fatal traffic accident last year.

Lawrence was pulled from the wreck unconscious and taken to the Suburban Hospital emergency room. Police did not suspect he had been drinking.

One of the emergency room nurses had been dating a police officer, according to Lawrence's defense attorney, Gary Offutt, and mentioned to the officer some weeks later that the blood samples taken from Lawrence by emergency room doctors showed he had been drinking.

The officer passed this information to the state's attorney's office, and the blood test results were subpoenaed. They were used against Lawrence in court, where he was convicted and given a three-year sentence. Efforts to suppress the blood-test evidence were rejected by the court. In October, the Court of Appeals decided not to hear an appeal against the use of the blood tests. Lawrence has now served six months of his sentence and is on a work-release program.

The Court of Appeals has also rejected an appeal by Baltimore County resident Robert E. Harper, who was convicted of vehicle manslaughter after a fatal accident in the county in October 1979. Harper's car struck the rear of a stalled, unlighted car. The driver of the stalled car was killed, and Harper was taken to a hospital.

There, despite Harper's objections, doctors took blood samples for medical purposes, according to his defense attorney, William E. Evans. Last month, the Maryland Court of Appeals refused to hear an appeal objecting to the use of this evidence. If the blood sample had not been allowed as evidence, Evans said last week, Harper "probably wouldn't have been convicted." Harper will soon begin serving a one-year prison sentence.

A third case affected by the Moon decision will go to trial within a few weeks, or early next year, in Upper Marlboro. Last week, John B. Whittle of Silver Spring was charged with manslaughter by automobile and homicide with a motor vehicle. State's Attorney Gene Whiffel, who is prosecuting, said the charges would not have been made if blood samples taken by doctors for medical purposes could not be used. "I think it's significant," he said of the Moon decision.

Whittle was involved in a traffic accident last Jan. 17 on Rte. 1 near College Park in which Stephen Prusik, 22, of Frederick County, was killed. Whittle was taken to a hospital where doctors took a routine blood sample. Police had not suspected Whittle of drinking until the results of the test were known.

The Moon decision came one day after a decision that the state's attorney and anti-drunk driving groups saw as a serious defeat. The Court of Appeals reversed a Talbot County circuit court decision that Michael Lee Loscumb was guilty of two counts of manslaugter by automobile and two counts of homicide by motor vehicle because blood samples were improperly taken.

Loscumb had been involved in a fatal car accident and taken to Easton Hospital. Police, suspecting that Loscumb had been drinking, asked emergency room doctors to take a blood sample for them. The doctors obliged, but the officers forgot to advise Loscumb he had the right to choose how the test would be conducted or to object to all testing.

Because of this omission, the Maryland Court of Appeals ruled that the blood test results should not have been used as evidence against Loscumb. Loscumb is now awaiting a new trial.

Prosecutors and police are often trapped by a network of legal requirements when trying to convict people accused of alcohol-related offenses, State's Attorney Gardner said.

Testing must take place within two hours of arrest. The suspect can demand that a physician of his own choosing administer the tests, and he must be given the choice of breathalizer or blood tests. If either of these is unavailable, the suspect can object to any testing.

Drunk or sober, the suspect is considered innocent if no other evidence is conclusive. If the suspect refuses to take a test, the arresting officer can report the refusal to the Department of Transportation, which can suspend the suspect's license for 60 to 120 days. But refusal to submit to testing is not considered an admission of guilt.

"It's really crazy," Gardner said. "The statute that has resulted is unbelievable. It really makes it very difficult."

Because of the complexities, she said, "any defense attorney willing to spend the time to make sure that all the stuff was done properly most likely will not have his client convicted."

But because of the Moon decision, she said, convictions will be much easier to obtain when serious accidents are involved. Often police officers do not suspect drunkeness, she said, especially when the drunk driver is unconscious and police are helping the injured rather than sniffing for alcohol fumes and looking for other indications of drunk driving.