On Line4 of OH Form Sched Of Adj Line36 there is a value. It is smaller than I expect. I assume it came from values in my Fed1040. What fields were used to calculate it?

Line 4 of the Unreimbursed Medical Care Expenses Worksheet (Ohio Schedule of Adjustments, Line 36) reflects amounts that you paid for medical care during the year that weren't included on lines 1-3 of the worksheet.  See the worksheet on page 27 of the IT 1040/SD 100 Instructions. 

So, line 4 would include medical expenses that weren't on:

• Line 1 of the worksheet includes unreimbursed dental, vision, and health insurance premiums paid during any portion of the year in which you were not eligible for Medicare or an employer-paid health care plan through your or your spouse’s employer
• Line 2 includes unreimbursed long-term care insurance premiums
• Line 3 includes unreimbursed dental, vision, and health insurance premiums paid during any portion of the year in which you were eligible for Medicare or an employer-paid health care plan through your or your spouse’s employer

You can see what might be included in your line 4 computation by looking at the various categories in the TurboTax medical expenses section of your federal return.  Any of these that wouldn't be included on lines 1, 2, or 3 of the worksheet would be included on line 4: 

• Prescription expenses
• Medical professional fees
• Medical facility fees
• Lab and x-ray fees
• Long-term care expenses
• Eye care expenses
• Medical supplies and equipment
• Medical travel
• Medical insurance premiums
• Long-term care premiums and
• Other

According to the What qualifies as "medical care" on line 4 of the Unreimbursed Health Care Expenses Worksheet? FAQ on Ohio's Income - Medical and Health Care Expenses page: 

For the purposes of this deduction, “medical care” has the same meaning as found in Section 213 of the IRC. Some examples include amounts paid for:

• Copays, deductibles and co-insurance;
• Prescription medication or insulin;
• Medical, dental and vision examinations and treatment by a certified health professional;
• Hospital costs and nursing care, including any eligible services provided at an assisted living facility; AND
• Eyeglasses, hearing aids, braces, crutches and wheelchairs.

These amounts are only deductible to the extent they exceed 7.5% of the taxpayer’s federal adjusted gross income. Refer to IRS Publication 502 for a comprehensive list of potentially eligible expenses.

Please note, while “medical care” does include medical insurance premiums, those amounts should not be included on line 4 if they are already reported on lines 1-3.

Thank you for this fine explanation.