The government will issue detailed guidelines outlining the technical requirements for testing federal workers for illegal drug use, an official said Saturday.

The guidelines, to be published Monday in the Federal Register, set forth "conditions under which (urine) specimens would be taken and . . . the standards labs would have to meet," said Campbell Gardett, a spokesman for the Department of Health and Human Services.The rules do not cover which employees will be tested or under what circumstances, Gardett said, confirming a report in The Washington Post. Such matters will be delineated in plans by individual departments and agencies, he said.

Currently, only the Defense Department and the Transportation Department test employees in sensitive positions.

Public employee unions have been resisting the tests, contending they violate workers' constitutional rights, and have filed suit to block them.

The publication of the technical requirements for testing is the first of three steps necessary before widespread testing of civilian government workers begins.

The second step, an HHS review of testing plans from departments and agencies, should be completed within several months, he said.

The third step, which he said should follow soon after that, is a report to Congress from the Office of Management and Budget estimating the cost of the program, which the Post said is preliminarily estimated at about $7 million.

The technical guidelines were proposed nearly 14 months ago in response to a September 1986 executive order issued as part of President Reagan's campaign for a drug-free workplace.

They are to guard against cheating by requiring that toilet water be dyed blue to prevent dilution of the urine sample and that the temperature of the samples be taken to prevent substitution by another sample smuggled into the toilet stall.