can I claim my wheelchair ramp as a medical expense?

It depends. The expense for a wheelchair ramp so that you or a family member could safely enter and exit a home does qualify as a medical expense. But, since this is a capital improvement, any increase in the value of the property would need to be deducted from the cost of the wheelchair ramp.

You must itemize your deductions to claim medical expenses. Also, medical expenses are only deductible for the amount in excess of 7.5% of your AGI. ‌For example, if your AGI is $50,000, only your medical expenses over $3,750 can be claimed as an itemized deduction.‌

Refer to IRS Publication 502 for more information.