In general, you can elect to treat gifts by cash or check as qualified contributions if the gifts were paid after August 27, 2005, to a qualified charitable organization (other than certain private foundations described in section 509(a)(3)). Qualified contributions are not subject to the overall limitations on itemized deductions or the 50% adjusted gross income limitation
Qualified contributions do not include contributions to organizations for which cash gifts are subject to a limit based on 30% of your adjusted gross income (such as contributions to veterans' organizations, fraternal societies, nonprofit cemeteries, and certain private non-operating foundations). Also, qualified contributions to a segregated fund or account for which you (or any person appointed or designated by you) have, or reasonably expect to have, advisory privileges with respect to distributions or investments based on your contribution.
Certain limits may apply if your qualified contributions are more than the AGI, minus all other allowable contributions. For details, see IRS Publication 526.