I received a reimbursement check for 2018 health insurance payments in February 2019. How do I record that in my 2019 taxes?

How to handle the reimbursement depends on if the Insurance premiums actually reduced your taxable income. If the medical insurance premiums were used to reduce your taxable income you need enter the premium amount that reduced the taxable income as Income on Line 21, Other income.

 

To determine the adjustment amount, do the following steps in order.

1. If you took the Standard Deduction on your 2018 return, you do not need to do anything.
2. If you added the medical insurance premiums to the rest of your Medical expenses the total medical expenses were not enough to add the medical expenses to your Itemized deductions, you do not need to do anything.
3. If you subtract the amount of the insurance premiums form the medical expenses in your Itemized Deductions and the result zero or a negative number, then the amount of the medical amount in your Itemized deduction is Your Adjustment Amount. 
4. If when you did the subtraction in Step 3, you still had an amount in the medical expenses then the amount of your insurance premiums is the Your Adjustment Amount.

If you need to enter an amount in the Miscellaneous income section, you should:

1. Select Federal in the black bar on the left.
2. Select Income & Expenses at the top of the screen.
3. Select Less Common Income. If the category is not shown select Other Income below the current incomes listed. Additional income selection will be shown.
4. Select Miscellaneous Income, 1099-A, 1099-C. 
5. Select Other reportable income
6. On the next screen you will be asked you if you received Any Other a taxable income? Select the Yes tab and enter the description as “Insurance Reimbursement” and then enter the amount.