ALB and atrial fibrillation: Since Δmax249 ≤ 9 μg/dl results were not affected by serum albumin and since the baseline serum total cortisol varied directly with albumin levels, we propose that Δmax249 ≤ 9 μg/dl, which means Δmax after high corticotropin dose may be a better option for AF diagnosis whenever measurement of free cortisol is not available.