As employers are preparing for 2013, there are several changes in the Patient Protection and Affordable Care Act that will affect them, and they must be ready to guide their employees through the new environment.

Notably, withholding for the Federal Insurance Contributions Act Medicare tax rate increase goes into effect in 2013. Under this provision, employees' hospital insurance tax rate is to increase by 0.9 percent for FICA wages of more than $200,000 or $250,000 for married couples who jointly file. While the tax rate for employers remains the same in 2013, employers are responsible for programming their payroll systems to withhold that 0.9 percent tax from employees' FICA wages.

This tax rate increase might come as a surprise to many people, says Steve Wojcik, vice president of public policy of National Business Group on Health, a nonprofit dedicated to representing large employers' perspective on national health policy issues in New York. When PPACA was first passed, much attention was given to the benefits of the bill, such as the extension of coverage to adult children at age 26 and the removal of lifetime limits, but this provision seemed to pass by quietly.