When are blood tests and scalp examinations necessary during a consultation for female hair loss?

Hello. I am a 35-year-old woman concerned about hair loss. I am writing to inquire about the extent to which the cause is identified during the initial consultation, rather than choosing the type of treatment first.

In hair loss consultations, what criteria are used to differentiate between cases where a diagnosis can be made solely through a medical history and a direct scalp examination, and cases where additional tests such as blood tests are considered? I am also curious whether everyone undergoes the same tests, or if the necessary items vary depending on the amount of hair loss or the pattern of progression.

Would it be helpful to bring my recent health checkup results if there are aspects that need to be checked in conjunction with other health conditions, such as iron or thyroid levels? I would also like guidance on what to disclose before the test if I am currently taking any supplements or medications, as well as items to inquire about in advance to avoid discontinuing them arbitrarily.

If tests are necessary, I would like to know if they can be done on the same day, if a separate appointment or fasting preparation is required, and how long it takes to receive the explanation of the results. If it is possible to monitor the progress without tests, I would also like to know about the changes that would require a follow-up appointment and the observation period. The attached image is for reference only, and materials showing specific test results or before-and-after treatment are no.