Clark can talk to Patty about her attendance problems but may not ask questions about her medical condition, including whether her cancer has returned, unless there is objective evidence that her absences stem from a medical condition.

Generally, an employer may ask disability-related questions or require an employee to have a medical examination when the employer knows about a particular employee's medical condition, has observed performance problems, and reasonably believes that the problems are related to a medical condition. At other times, an employer may ask for medical information when it has observed symptoms, such as extreme fatigue or irritability, or has received reliable information from someone else (for example, a family member or coworker) indicating that the employee may have a medical condition that is causing performance problems. Often, however, poor job performance is unrelated to a medical condition and generally should be handled in accordance with an employer's existing policies concerning performance.

Source: EEOC Publication: Revised Questions and Answers about Cancer in the Workplace and the Americans with Disabilities Act, https://www.eeoc.gov/laws/types/cancer.cfm, reported in Employment Practices Guide, New Developments ¶5371.