The Two Day Rule

The FMLA Regulations are available in PDF format and you can download them from http://www.nalc.org/depart/cau/fmla.html This is the National Association of Letter Carriers web site and they have a lot of good information here.
When you download the Regulations, in Adobe Acrobat, use the search feature and look for "Two Business Days". You will find that the FMLA Regulations revolve around Two Business Days and you will find 21 results.
The most important thing you will find is that management Must let you know within "two business days" after turning in your FMLA Certification if it has been accepted or not. 825.208(b)(1) If they haven't let you know by then, a grievance should be filed to have it marked as approved. I usually give them 3 week days so an arbitrator can see I've given management the benefit of the doubt.
If you return from an illness and you want to clam this as an FMLA absence, then you must let management know within "two business days".
825.306(b) gives that an employee has 15 days to provide the FMLA certification after management is given notice the leave is for FMLA reasons.
If you are in trouble, download the FMLA Regulations PDF and protect yourself.