What immediate action is required after a specimen is deemed invalid?

When a specimen is deemed invalid, the appropriate and immediate action is to collect a new specimen for re-evaluation. This process is crucial because an invalid result means that the original specimen cannot provide reliable information regarding the presence or absence of substances. Therefore, additional testing is necessary to ensure that accurate and reliable findings are obtained.

Collecting a new specimen allows for a fresh analysis using a completely new sample, which can help clarify any issues that arose with the previous sample. This practice also ensures compliance with regulatory protocols governing drug testing procedures, as it protects both the employer's interests and the rights of the employee being tested. This step not only facilitates the need for proper documentation but also retains the integrity of the drug testing process, providing a chance to confirm the employee's status accurately.

The other options don’t address the immediate requirement for a retest in a structured manner. A follow-up assessment with a health professional might be appropriate in other circumstances, but it is not a direct response to invalidation. Re-testing the same specimen isn't feasible since the validity issue prevents it from being a reliable source. While informing the employee of the invalid result is necessary, it does not fulfill the requirement for taking an action that resolves the invalid status of a specimen.