They said he also passed a voluntary polygraph test.

No wonder public health officials overwhelmingly prefer voluntary tests.

These patients were approached, and a group selected for reliability agreed to undergo voluntary tests of the vaccines being developed.

He took a voluntary test for drug use one week ago last Thursday, and the result was positive.

This voluntary test is designed for instructors who would like their driving/riding skills to be tested to the highest standards.

Only half of the infected mothers are now being identified through voluntary tests, leaving about 200 to 300 infected babies unidentified each year.

The voluntary tests would be developed by the teacher-dominated board.

Nationalized voluntary tests in five core subjects would be used in college admissions and the job market.

How could they recommend to their patients a "voluntary" test that they themselves had not undergone?

Twenty thousand amateur pianists were taking voluntary tests to gauge their level of skill.