.svg)
When an employee needs time away from work — for surgery, a chronic condition, pregnancy complications, a mental health episode — the request almost always comes with a question HR has to answer: What documentation can we actually require?
It sounds like a straightforward question. It isn't. The laws governing what you can and can't ask a healthcare provider to certify are layered, overlapping, and increasingly state-specific. Ask for too little and you're exposed. Ask for too much and you're exposed differently. Ask for the right thing at the wrong time and you're still exposed. Getting this wrong can mean discrimination claims, retaliation complaints, or leave-law violations — and it happens more often than most HR teams want to admit.
This post covers the four federal laws that shape medical certification requirements, what each one actually allows (and limits), and what HR teams in benefits, leave, accommodations, and compliance need to keep on their radar.
One thing before we start: nothing here is legal advice. Please loop in your employment counsel for anything specific to your organization or jurisdiction.
1. The Family and Medical Leave Act (FMLA)
Enacted: 1993 | Enforcer: U.S. Department of Labor | Employer threshold: 50+ employees
The FMLA is the foundation — the law most HR teams learn first and reference most often. It gives eligible employees up to 12 weeks of unpaid, job-protected leave per year for qualifying reasons: their own serious health condition, caring for a family member, or the birth or placement of a child.
You may (but aren't required to) ask for medical certification from the employee's healthcare provider. The DOL provides standardized forms — WH-380-E for the employee's own condition, WH-380-F for a family member — and using them is broadly considered best practice. One thing the forms won't ask for, and that you can't require: a diagnosis. Certification confirms a serious health condition exists. That's the limit.
If you do require certification, employees get at least 15 calendar days to return it. If what they submit is incomplete or insufficient, you have to tell them in writing and give them at least 7 days to fix it before you can deny leave. No shortcuts there.
Recertification is generally permitted no more than every 30 days — though sooner is allowed if there's a significant change in the employee's condition. And when someone returns from FMLA leave taken for their own health condition, you can require a fitness-for-duty certification confirming they can perform the essential functions of the job, as long as you stated that requirement upfront in the designation notice and apply it consistently.
A few things that catch employers off guard: second and third opinions are only permitted for initial certifications (at the employer's expense), not for recertifications or fitness-for-duty. All FMLA medical records belong in a separate, confidential file — not the personnel file. Supervisors can be told about work restrictions and necessary accommodations, but they don't get access to the underlying medical information.
2. The Americans with Disabilities Act (ADA)
Enacted: 1990, significantly amended 2008 | Enforcer: EEOC | Employer threshold: 15+ employees
The ADA is where things get complicated — especially for teams that treat it as a separate track from leave management. It isn't. The ADA governs the broader obligation to accommodate employees with disabilities, and that often includes leave as a form of accommodation. The two laws run concurrently more often than people expect.
Under the ADA, you can request medical information only when the disability and the need for accommodation aren't obvious, and only to the extent necessary to confirm the disability exists, understand what functional limitations are at play, and identify possible accommodations. You can't demand a specific diagnosis, and documentation requests should be narrow. If your form is asking for more than you actually need to make an accommodation decision, you're probably asking for too much.
Here's the part that gets employers into trouble most often: ADA obligations don't stop when FMLA leave runs out. An employee who has exhausted 12 weeks may still be entitled to additional unpaid leave as a reasonable accommodation — unless you can show it creates an undue hardship. Courts have generally found that indefinite leave (no clear return-to-work date) isn't reasonable, but a fixed extension of a few additional weeks often is. Automatically terminating employees when their FMLA runs out, without stopping to evaluate what the ADA requires, is one of the most common and costly mistakes in this space.
The interactive process isn't optional. When an employee requests an accommodation — including leave — you're expected to engage in a good-faith, documented dialogue about effective options. “We don't have a process for that” isn't a defense.
3. The Pregnant Workers Fairness Act (PWFA)
Enacted: 2023 | Final EEOC rule effective: June 18, 2024 | Enforcer: EEOC | Employer threshold: 15+ employees
The PWFA is the biggest addition to this compliance landscape since the 2008 ADA amendments, and a lot of HR teams are still catching up to what it actually requires. It mandates reasonable accommodations for employees and applicants with limitations related to pregnancy, childbirth, or related medical conditions — unless doing so would cause undue hardship.
What's different here is how the law treats documentation. The EEOC’s final rule takes a notably more restrictive stance than either the FMLA or ADA: you should only request supporting documentation when it's reasonable to do so given the circumstances. That's a higher bar than many teams realize.
Documentation generally isn't reasonable when the limitation is obvious or already known, when the employee is asking for one of several “predictable assessments” — things like carrying water, extra restroom breaks, or a stool to sit on — or when your own internal policies would give any employee the same adjustment anyway. When documentation is appropriate, you can only request what's minimally necessary to confirm a condition exists, that a workplace change is needed, and what kind of adjustment is involved.
The covered conditions are also broader than people assume. The PWFA covers miscarriage, postpartum depression, lactation, prenatal care, C-section recovery, and conditions exacerbated by pregnancy like carpal tunnel, migraines, and incontinence — not just the pregnancy itself.
Worth flagging: if you request documentation and your request wasn't reasonable under the PWFA, you can't use an employee's failure to provide it as grounds to deny the accommodation. Unreasonable documentation requests can themselves support an interference or retaliation claim. And because the PWFA doesn't replace the FMLA or ADA, all three may apply to the same situation at the same time.
4. The Genetic Information Nondiscrimination Act (GINA)
Enacted: 2008 | Enforcer: EEOC | Employer threshold: 15+ employees
GINA tends to get overlooked in leave and accommodation conversations, but it creates real risk whenever you're collecting medical documentation — and it's worth understanding exactly why.
GINA prohibits employers from requesting, requiring, or purchasing genetic information about employees or their family members. Genetic information includes family medical history, which shows up in certifications more often than people realize — sometimes explicitly, sometimes implied.
The practical issue: even though you're legitimately requesting certification under the FMLA or ADA, that certification form might elicit genetic information. The protection GINA gives you is a safe harbor: if your forms include language expressly instructing healthcare providers not to provide genetic or family medical history information, you're generally protected if a provider includes it anyway.
The DOL-issued FMLA forms include this recommended language. Make sure your forms — including any custom forms you've built — do too. If you ever receive genetic information inadvertently, don't use it in any decision, for any reason.
Federal law sets the floor, but an expanding and increasingly complex body of state and local law often goes further. A few things worth watching:
State paid family and medical leave (PFML) programs
As of 2026, more than a dozen states have active paid family and medical leave programs — California, New York, New Jersey, Massachusetts, Connecticut, Washington, Oregon, Colorado, and others, with Delaware and Minnesota recently coming online or in transition. More are in progress.
Each has its own certification requirements that sometimes conflict with FMLA standards. Washington accepts FMLA forms, a doctor's note, or its own state form. Colorado's FAMLI program offers up to 12 weeks, plus an additional 4 for pregnancy complications. Massachusetts covers up to 20 weeks for an employee's own condition — significantly more than federal FMLA.
If you have employees in multiple states, you need to know which certification process applies to which leave program — and make sure employees are getting accurate information about their rights under each.
State accommodation laws
Many states have disability accommodation laws that are broader than the ADA: lower employer thresholds, wider definitions of disability, and tighter documentation restrictions. California's FEHA applies to employers with 5 or more employees and has its own interactive process requirements. Some states enacted pregnancy accommodation laws before the federal PWFA existed. A jurisdiction-by-jurisdiction review is worth doing if you haven't recently.
Paid sick leave and documentation restrictions
A growing number of states and municipalities explicitly restrict when employers can ask for documentation at all. In many jurisdictions, requiring a provider's note for absences under three days is prohibited. It's a compliance issue and — maybe more practically — a quick way to damage trust with employees who are already dealing with something hard.
That's the core framework. The laws themselves aren't going to get simpler, and the state layer keeps expanding. But knowing where the lines are — and where the common missteps happen — puts HR teams in a much better position to handle these situations well.
Sources:
