Are Low-Volume PEG Preps Covered by Medicare? A 2025 Guide

Preparing for a colonoscopy is a critical step for a successful screening, but the process has long been a source of dread for patients, primarily due to the large volume of laxative fluid required. Newer, low-volume preparations have made this process much more tolerable. However, for Medicare beneficiaries, accessing these patient-friendly options often comes with a frustrating and unexpected price tag.

While the colonoscopy itself is typically covered as a preventive screening, many find themselves paying out-of-pocket for the necessary prep kit. This guide synthesizes the latest research and insurance data to explain why this happens, quantify the costs, and provide actionable steps to help you get your low-volume PEG prep covered by Medicare.

The Colonoscopy Prep Dilemma: Why Low-Volume is Preferred

Effective bowel preparation is essential for a clear view of the colon, allowing doctors to detect and remove precancerous polyps. For decades, the standard has been a high-volume solution containing polyethylene glycol (PEG), requiring patients to drink up to four liters—more than a gallon—of liquid.

Due to the unpleasant taste and sheer volume, poor preparation occurs in at least 20% of colonoscopies, often because patients cannot tolerate drinking the full amount. This can lead to missed polyps or the need for a repeat procedure.

Low-volume preps have emerged as a game-changer. These solutions, which include brands like Plenvu®, Suprep®, and Clenpiq®, require drinking only one to two liters of liquid, making the process significantly easier to complete. Improved tolerability leads to better patient compliance, which in turn results in a cleaner colon and a more effective screening.

A graphic comparing a large 4-liter jug for a high-volume prep next to a smaller 1-liter bottle for a low-volume prep, highlighting the difference in patient experience.

Caption: Low-volume preparations significantly reduce the amount of liquid patients need to consume, improving tolerance and adherence.

Understanding Medicare Coverage for Colonoscopy Preps

The main source of confusion and frustration for patients is the separation in how Medicare covers the procedure versus the prep kit. This creates what many call a "coverage loophole."

The "Medicare Loophole": Part B vs. Part D Coverage

• The Procedure (Medicare Part B): A screening colonoscopy is considered a preventive medical service. As such, it is covered by Medicare Part B. If you see a provider who accepts Medicare, the procedure itself often has a $0 cost-sharing for you.
• The Prep Kit (Medicare Part D): The bowel prep kit, however, is classified as a prescription drug. This means it is covered under a Medicare Part D prescription drug plan or a Medicare Advantage (Part C) plan that includes drug coverage.

Because Part D plans are administered by private insurance companies, each has its own formulary (list of covered drugs), tiers, and cost-sharing rules (deductibles, copayments). This is where the out-of-pocket costs originate.

The Cost Disparity: Low-Volume vs. High-Volume Preps

According to a 2023 study published in Gastroenterology that analyzed millions of insurance claims, Medicare beneficiaries face a steep financial penalty for choosing more tolerable low-volume preps.

A study highlighted by the American Journal of Managed Care® found that a staggering 83% of Medicare beneficiaries paid out-of-pocket for their bowel prep, a clear contradiction of the Affordable Care Act's (ACA) mandate for no-cost preventive care. The cost difference between prep types is stark:

Prep Type	Medicare Claims with OOP Costs	Median OOP Cost (for those who paid)
Low-Volume Prep	90%	$55.99
High-Volume Prep	75%	$8.00

Source: AJMC®, Colon Cancer Coalition

This disparity exists because high-volume PEG solutions (like GoLYTELY®) are often available as inexpensive generics and are placed on the lowest, most affordable tiers of a drug plan's formulary. In contrast, low-volume preps are typically newer, brand-name products placed on higher tiers, which come with higher copayments.

Common Low-Volume PEG Preps: What to Know

While many low-volume preps are available, some of the most common ones that use PEG or similar osmotic laxatives include:

• Plenvu®: A 1-liter PEG-based prep, one of the lowest volumes available.
• MoviPrep®: A 2-liter low-volume PEG solution.
• Suprep Bowel Prep Kit®: Uses sodium sulfate, potassium sulfate, and magnesium sulfate in a 2-dose, low-volume regimen.
• Clenpiq®: A ready-to-drink, low-volume prep that comes in two small bottles.
• Sutab®: A tablet-based option, for those who have extreme difficulty with liquid preps.

Coverage for these specific brands varies dramatically between Medicare Part D plans.

A collage of different low-volume colonoscopy prep kit boxes, like Plenvu, Suprep, and Sutab.

How to Get Your Low-Volume Prep Covered by Medicare

If your doctor recommends a low-volume prep, don't assume you'll have to pay the full price. Be proactive. Here is a step-by-step process to help you secure coverage.

Step 1: Check Your Plan's Formulary

Before your appointment, contact your Medicare Part D or Medicare Advantage plan provider, or check their website for the plan's drug formulary. See if your prescribed prep is on the list and what tier it falls under. This will give you an idea of your expected copay.

Step 2: Request a Formulary Exception

If the prescribed prep is not on the formulary, you are not out of options. Your doctor can request a "formulary exception" from your insurance plan. This is a formal process to get a non-covered drug approved.

The key to a successful exception is a strong supporting statement from your physician. The doctor must explain to the plan why the non-formulary low-volume prep is medically necessary for you. This could include reasons like:

• You have a history of intolerance to high-volume preps.
• You have a medical condition (like kidney issues or dysphagia) that makes a high-volume prep unsafe or impossible.
• Formulary alternatives have been tried and were ineffective.

Once the request is submitted, the plan must typically make a decision within 72 hours.

Step 3: Appeal a Denial

If your plan denies the exception request, you have the right to appeal. The first step is to request a redetermination from the plan. Your plan's denial letter will include instructions on how to file an appeal.

Alternative Strategies

If the exception process is unsuccessful, consider these other options:

• Ask for Alternatives: Talk to your doctor about other low-volume preps that are on your plan's formulary.
• Look for Assistance: Some drug manufacturers offer coupons or patient assistance programs that can lower costs. Check the manufacturer's website for your prescribed prep.
• Switch Plans: During Medicare's annual Open Enrollment Period (October 15 - December 7), you can compare Part D plans and switch to one that offers better coverage for the medications you need.

The Bottom Line: Advocating for Your Health

The financial barriers to accessing more tolerable low-volume colonoscopy preps under Medicare are real and well-documented. However, understanding the system is the first step toward overcoming them.

Have an open conversation with your doctor about both the clinical need for a low-volume prep and the potential costs. By working together, you can navigate the formulary exception process and advocate for the preparation method that gives you the best chance of a comfortable and effective life-saving screening.

References

• Cost of colonoscopy prep kits with Medicare - Medical News Today
• Many Still Pay for Colonoscopy Prep Despite ACA Coverage Mandate - The American Journal of Managed Care®
• Medicare Coverage for Colonoscopy Prep Kits - Healthline
• Medicare Coverage for Colonoscopies - Official U.S. Government Site for Medicare