When it comes to interviewing questions, the ADA requires that
employers phrase their questions with extreme care. For example, it
is unlawful to ask the following questions to job applicants:

Are you disabled?
Do you have any disability that would prevent you from
doing this job?
Will you need any sort of accommodation or special equipment
to perform the job duties?
How many days were you sick last year?
Have you ever attended a drug or alcohol rehabilitation program?
Are you capable of lifting two-pound cans?

Okay, now that you know what you can’t ask; what can you ask? The simple litmus test is this: ADA interviewing questions must focus on a candidate’s ability to get the job done, not on the likelihood that the disability will get in the way. Consequently, the question, ‘‘Can you perform the essential functions of this job with
or without accommodation?’’ is allowable. Furthermore, you can
ask, ‘‘Are you capable of lifting two-pound cans and placing them
on five-foot shelves in the order of their date of receipt?’’

Phrasing the question this way (as opposed to how it’s phrased
earlier, ‘‘Are you capable of lifting two-pound cans?’’) is allowable
because it relates to the actual job duties. Focusing on specific abilities relative to job performance is allowable; focusing on abilities in general could land you in hot water if a rejected applicant files a
complaint with the EEOC or pursues a private lawsuit.

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You also can’t ask how many sick days the employee took that year.
However, you have the right to ask, ‘‘How many days of unscheduled
leave have you incurred this year?’’ The difference in phraseology
is simply this: ‘‘Sick days’’ relate directly to medical conditions that may be covered by the Act. ‘‘Unscheduled leave days,’’ on the other hand, may have nothing to do with illness or injury; instead, they may have to do with taking unscheduled vacation days or an
unapproved personal leave of absence.

An additional note of interest: Once an applicant is given a conditional job offer, you are permitted to require the individual to
undergo a physical or medical exam. Physical fitness tests are not
medical exams. These types of tests measure abilities, not disabilities, and may therefore be given in the pre-employment process (i.e., before extending a conditional employment offer). Similarly, a test to determine whether an employee is using drugs is not considered a medical exam under the ADA. You may likewise conduct drug tests designed to accurately identify illegal drugs before a conditional job offer is made. Of course, you must ensure that such exams are given uniformly to all candidates. The results of the exam must be kept in a separate, confidential file and used only for legally permissible purposes of evaluating candidates’ suitability for the job.

Finally, if a medical exam screens out an applicant from employment,
you must be able to demonstrate that the requirements that excluded the individual from employment are job related and
consistent with business necessity. Furthermore, you must also be
able to demonstrate that the individual can’t perform the job duties
even with a reasonable accommodation. Remember, however, that
the ADA is still a relatively new and untested law. Because the
courts are still evaluating plaintiff attorneys’ interpretations of particular ADA provisions and because it is unclear what is required of
employers to demonstrate ‘‘business necessity,’’ you should discuss
the merits of particular cases with qualified legal counsel.

Taken From : The Hiring and Firing Quention and Answer Book