Standard deduction

The standard deduction is a flat amount the IRS lets every household subtract from income without itemizing on Schedule A. The figure depends on filing status (single, married filing jointly, head of household) and updates each year for inflation. For most households it is high enough that itemizing only makes sense when medical, state-tax, mortgage, and charitable totals together clear it.

After the 2017 Tax Cuts and Jobs Act doubled the standard deduction, the share of returns that itemize dropped sharply. Households that itemized for years before 2018 sometimes still file Schedule A out of habit; the math has changed.

The standard deduction is not a competitor to the medical line in isolation. The comparison is the full Schedule A total (medical above the AGI floor, plus state and local taxes, plus mortgage interest, plus charitable gifts, plus the smaller categories) against the standard deduction. If the standard deduction wins, none of the Schedule A categories show up on the return; the medical line reads as zero, not because the medical expenses were not real but because the household chose the simpler filing path.

The decision is annual. A household can itemize one year and take the standard deduction the next, depending on which side of the line that year's expenses fall.

For households with a documented celiac diagnosis, the medical line on Schedule A is real. Whether it lands on a given year's return depends on the standard-deduction comparison, not on whether the gluten-free premium was tracked. Track it either way; the tracking is the part that holds up later.

For the full walkthrough, read What Publication 502 actually says about celiac.