"Additional diagnostics" refers to extra tests or procedures that are performed to gain more information or to further understand a certain issue or problem. Full definition
The need for additional diagnostic tests is determined based on the results of the medical history, physical examination and initial laboratory tests. (petsmagazine.com.sg)
You were referred to our hospital by your primary care veterinarian for additional diagnostic testing, medical evaluation, and treatment by a specialist for your pet's illness. (uvsonline.com)
Your veterinarian may recommend additional diagnostic tests based on the results of initial examinations. (petsmagazine.com.sg)