The standard deduction for Married Filing Jointly is $12,600. But simply adding up your raw totals for deductions and comparing it to the standard deduction isn't enough. There are certain itemized deductions that have limitations based on Adjusted Gross Income (AGI).
One of those deductions is for medical expenses. Once you add up your medical deductions, you'll only be able to deduct the amount that exceeds 10% of your AGI (7.5% if age 65+). The higher your AGI, the higher the threshold for claiming the medical expenses.
Another deduction with an AGI threshold is Miscellaneous Deductions -- things like job-related expenses, union dues, tax prep fees, and others. These are called "2%" misc deductions because you only start to get them once they (as a group) exceed 2% of your AGI.
With these types of limited deductions, the amount actually deductible usually winds up being less than people expect.