Observers say the primary problem associated with diabetes and the Family and Medical Leave Act is intermittent leave.

Under FMLA, an employee at an organization with at least 50 workers can take up to 12 weeks of unpaid job-protected leave a year for several specific reasons, one of which is recovery from a medical condition.

Employers must permit employees to take intermittent FMLA leave in increments that are the smallest time period the employer uses in its payroll system to account for absences.

Because of the nature of the disease, diabetic employees may need relatively brief periods of time off, which creates scheduling problems for employers, say observers.

Frank Alvarez, an employer attorney with Jackson Lewis L.L.P. in White Plains, N.Y., said FMLA "becomes a particular challenge for employers when diabetic employees need intermittent leave because they are having episodic-type bouts of diabetic problems—either their blood sugar becomes uncontrolled, or they have other related health conditions—because it's not under control and they may need to be out for work a day here or a day there, or maybe even part of a day here or part of a day there."

A frequently related problem is that the need to take time off because of diabetes is unforeseeable, and the employee can give as short a notice of the need for leave as is practical under the circumstances. "This results often in unscheduled, unplanned absences, and employers have great difficulty managing their operations when they have little notice of an individual's absence from work," Mr. Alvarez said.

Careful recordkeeping is important, said Craig A. Crispin, of Portland Ore.-based Crispin Employment Lawyers, who primarily represents plaintiffs. "I've caught more than a few employers violating FMLA on intermittent leave simply because they failed to keep records. They simply put down absences" and then say the employee was fired for excessive absenteeism.

Mr. Crispin said if he can prove that even one of those absences should have been covered by the FMLA, "then they've violated the law and I can win that case pretty easily."

Employers sometimes mistakenly believe that eligibility for FMLA requires a minimum three-day period of incapacity, when in fact that is not required for chronic serious health conditions including diabetes, said Loring N. Spolter, a Fort Lauderdale, Fla.-based solo attorney.

However, John W. Griffin Jr., an attorney with Marek, Griffin & Knaupp in Victoria, Texas, said he has not found FMLA to be an issue in about 20 years of representing diabetics.

"Most of the time diabetic patients are able to adjust and to manage their diabetes without taking FMLA leave," Mr. Griffin said.