While general account eligibility is a leading concern for FSA users, another 30.8 percent said the over-the-counter (OTC) Rx provision is the most confusing.

Flexible spending accounts (FSAs) aren't new, and they aren't particularly sexy. But each year, more than 35 million Americans enroll in the tax-free accounts to help pay for qualified health care needs for themselves and their dependents.

Earlier this year, FSAstore.com surveyed more than 1,000 customers to explore knowledge gaps and uncover what matters most to individuals when it comes to using their accounts. Following is a summary of insights from this survey that can help HR professionals plan communications and education efforts for the upcoming open enrollment season.

1. Account holders remain confused about where and how to spend FSA funds.

Interestingly, 40 percent of FSAstore.com survey respondents said they've had an FSA card transaction or claim denied in the past. This can happen when a product or service is not an eligible expense, if the vendor does not accept FSA debit cards or if the expense falls outside their current plan year.