Last Updated on November 20, 2025 by MyHRConcierge

The Sixth Circuit’s ruling in Jackson v. United States Postal Service represents one of the most consequential FMLA decisions in recent years. For HR professionals and employers navigating the complexities of intermittent leave, the decision provides both guidance and boundaries, underscoring the need to understand the purpose and limitations of medical certifications- especially when working with conditions that produce unpredictable absences. 

This “Beyond the Bench” blog post breaks down the ruling, explores the court’s reasoning and translates the implications into actionable strategies for employers. 

Jackson v. United States Postal Service at a Glance 

The plaintiff, a longtime USPS employee, lives with sickle cell anemia: a chronic illness characterized by random and sometimes severe pain crises. These flare-ups occur without warning and often prevent affected individuals from performing basic daily activities, let alone attending work. As required under the FMLA, the employee obtained a medical certification from his nurse practitioner. The certification estimated that he would likely experience approximately two flare-ups per month requiring intermittent leave. 

USPS, like many employers, interpreted this projected frequency as a strict maximum. Over time, when the employee experienced months with more than two flare-ups, he was disciplined and ultimately separated from employment for “excessive” absences beyond the certified estimate. 

A lower court sided with USPS, accepting the view that the number on the certification effectively defined the outer limit of the protected leave. But, the Sixth Circuit sharply disagreed, concluding that the employer had fundamentally misunderstood the nature of medical certifications in cases involving unpredictable conditions. 

Why the Estimate Is Not a Cap 

In its opinion, the Sixth Circuit made clear that FMLA medical certifications are intended to inform employers of the employee’s likely needs, not impose an absolute ceiling. Healthcare providers are required to supply their best estimate of the frequency and duration of episodes, but when a condition is inherently erratic, these estimates cannot function as hard limits. 

The court emphasized that chronic conditions often worsen or fluctuate due to countless variables, such as stress levels, weather changes, physical exertion or even no identifiable cause. Expecting employees to adhere strictly to a projected frequency disregards medical reality and undermines the protective purpose of the FMLA. The court also noted that penalizing an employee for experiencing flare-ups beyond an estimated amount effectively punishes them for the severity of their condition, which directly contradicts the statute’s intent. 

By treating the certification estimate as the final word, USPS imposed restrictions that the FMLA simply does not support. The Sixth Circuit’s ruling clarifies that the law protects leave needed due to the medical condition, not merely the amount anticipated by a provider. 

What Employers Can Still Do 

Although the ruling limits the use of certification estimates as strict caps, the court acknowledged that employers must still be able to manage their workforce effectively. The decision reinforces several tools employers may use to ensure that intermittent leave is legitimate, necessary and manageable.  

Request Recertification 

When an employee’s leave usage significantly exceeds the estimate in the certification, the employer may request recertification from the healthcare provider. The threshold for “significant change” is not rigid, but the Department of Labor and multiple courts have interpreted it broadly enough to give employers meaningful oversight. Recertification may reveal that the employees’ condition has worsened, that their needs have changed or that prior estimates were too conservative. 

Requesting recertification is distinct from disciplining the employee. It allows employers to reconfirm the legitimacy of the absences without violating FMLA protections. 

Seek Clarification or Authentication 

If the medical certification contains unclear, incomplete, or confusing information, employers may seek clarification or authentication through HR- not through the employee’s direct supervisor- to ensure the form is accurate and complete. This safeguard helps prevent misunderstandings and allows employers to manage intermittent leave appropriately. 

Continue Enforcing Neutral Attendance Policies

Absences not covered by the FMLA may still be subject to the employer’s attendance and corrective action policies. The key is ensuring that protected leave is not improperly categorized as unprotected simply because it exceeds an estimate. 

What Employers May Not Do 

The Sixth Circuit drew firm lines around employer behavior likely to violate the FMLA: 

• Employers may not treat the provider’s estimate as an entitlement limit or quota. 

• Employers may not automatically discipline employees for exceeding an estimated frequency when the underlying medical condition is unpredictable. 

• Employers may not assume abuse or misuse based solely on the number of occurrences. Evaluating FMLA misuse requires evidence, not mathematical deviation. 

This distinction is crucial: employers may regulate conduct, patterns and compliance, but not the natural variability of a chronic medical condition. 

What This Means for Employers Nationwide 

While this ruling is binding only in the Sixth Circuit, FMLA cases often influence one another across jurisdictions. The decision aligns closely with Department of Labor interpretations, meaning other courts are likely to adopt similar reasoning. Employers operating nationally should consider this ruling a signal to harmonize their FMLA practices with this more flexible interpretation of certification estimates. 

Relying on strict numerical limits is increasingly risky, and HR leaders should treat this ruling as guidance for modernizing compliance. 

Looking Ahead: Building a Smarter, More Compliant FMLA Strategy 

The Jackson decision reinforces a central principle of the FMLA: the law is designed to accommodate the realities of serious health conditions, not force them into predictable patterns. For employers, this ruling encourages a more nuanced, medically informed approach to intermittent leave: one that emphasizes documentation, recertification and fair application of policy rather than rigid reliance on estimated numbers. 

For more insights or assistance with your organization’s HR strategy, handbooks or compliance efforts, contact MyHRConcierge today at ccooley@myhrconcierge.com, 855-538-6947 ext. 108. Or, schedule a free consultation below:

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