Question: What diagnosis code would I use if the patient is requesting labs for work? Virginia Subscriber Answer: You should go one of the following codes for the visit: But as the patient is also requesting lab tests required for her employment, and if you were screening for a particular disease, you’d use the screening code that applies. For instance, a nurse might need a screening test for tuberculosis prior to being hired and the code for this test would be Z11.1 (Encounter for screening for respiratory tuberculosis).