You are responding to a post that applies to tax years before 2017; the date on the post was corrupted in the movement of this thread from the old Intuit forum.
The threshold for the amount that is exempt from the early-distribution penalty due to unreimbursed medical expenses is defined in the law to be the same as that for deductibility on Schedule A. For tax year 2018 the threshold is 7.5% of AGI. For 2019 and beyond it goes back to 10% of AGI. In other words, the amount of an early distribution that is exempt from penalty under this exception is always the same amount that would appear on Schedule A line 4 if you were to itemize (assuming that the distribution exceeds the Schedule A line 4 amount).
