Final answer:
In Addison's Disease, the assessment of cortisol levels and adrenal antibodies, particularly to 21-hydroxylase, is crucial for diagnosis, along with monitoring ACTH, sodium, and potassium levels.
Step-by-step explanation:
The most important assessment parameter in Addison's Disease, which is an adrenal insufficiency resulting in the reduced production of cortisol, is the level of cortisol and adrenal antibodies, particularly antibodies to 21-hydroxylase (21-OH). Cortisol levels are directly affected in this condition, and detecting adrenal antibodies can confirm if it's autoimmune Addison Disease (AAD). In addition to cortisol, levels of adrenocorticotropic hormone (ACTH), sodium, and potassium in the blood are critical to assess, as they help in diagnosing the disorder and determining its severity. Symptoms such as hyperpigmentation, hypotension, and electrolyte imbalance support the diagnosis.