Final answer:
The tourniquet should be applied for a maximum of 1 minute to avoid tissue damage and ensure accurate blood test results.
Step-by-step explanation:
The maximum time a tourniquet should remain on a patient's arm is 1 minute. Keeping a tourniquet on for longer may cause complications such as tissue damage or inaccurate test results due to hemoconcentration and stasis. It is critical to limit the time of tourniquet application to avoid these issues, ensuring the safety and well-being of the patient, as well as the accuracy of any blood tests being performed.