What is necessary for a health department to formally challenge a subpoena?

For a health department to formally challenge a subpoena, it is necessary to file a motion to quash, which is a legal term that refers to the process of asking the court to invalidate or nullify the subpoena. This action is typically performed by an attorney representing the health department, as they have the legal expertise to argue whether the subpoena is valid or if there are grounds to challenge it based on applicable laws and regulations.

Filing a motion to quash allows the department to present its reasons for opposing the subpoena, which may include issues such as relevance, burden, or confidentiality concerns regarding the requested information. This process ensures that the health department's rights and obligations are respected under the law, and serves as a formal mechanism to dispute the subpoena in a legal context.

The other options, while they may reflect steps that could occur during the process of challenging a subpoena, do not encapsulate the formal legal requirement needed to initiate the challenge. A written statement or approval from the director may support the challenge but isn’t the primary legal means for contesting a subpoena. Investigating the subpoena's origin may provide context but does not fulfill the legal requirement necessary for challenging it.