(a) A recipient may not use an employment test or other selection criterion that screens out or tends to screen out handicapped persons unless the test score or other selection criterion, as used by the recipient, is shown to be job-related for the position in question.

(b) A recipient shall ensure that employment tests are adapted for use by persons who have handicaps that impair sensory, manual, or speaking skills except where those skills are the factors that the test purports to measure.