If you are a female (22) suffering from hair loss/hair thinning at the front portion of the head what tests can be carried out to determine the cause?

Several tests: Ferritin level, thyroid hormone, free testosterone level. Most likely this is hereditary.

Please see your derm: It could be female pattern alopecia, but it could also be related to an underlying medical problem. In a young woman, it is necessary to rule out iron deficiency anemia and thyroid disorders, among other things. It can also occur in the setting of extreme stressors, such as childbirth, surgery, or loss of a loved one. Blood tests should be ordered and a scalp biopsy may need to be performed.

Hair Loss Diagnosis: In my practice, we determine the cause of hair loss by doing a comprehensive medical evaluation which may include an inventory of risk factors, medical history, hair loss history, blood work, genetic testing (hairdx) &other lab tests, biopsy, detailed exam of the hair and scalp, measurements using the haircheck trichometer, haircam microscope evaluation of hair caliber &density &more...