Glossary term

True Out-of-Pocket (TrOOP)

True out-of-pocket, or TrOOP, is the Medicare Part D measure of spending that counts toward a beneficiary's annual prescription drug out-of-pocket threshold.

Updated

May 19, 2026

Read time

3 min read

What Is True Out-of-Pocket (TrOOP)?

True out-of-pocket, or TrOOP, is the Medicare Part D measure of spending that counts toward a beneficiary's annual prescription drug out-of-pocket threshold. It is used to track covered Part D drug costs that count toward the point where the enrollee reaches the plan's out-of-pocket limit or later coverage stage.

TrOOP is not simply every dollar a person spends on health care. It is specific to Medicare drug coverage and depends on whether the cost is for covered Part D drugs and whether the payment counts under Medicare rules.

Key Takeaways

  • TrOOP is used in Medicare Part D prescription drug coverage.
  • It tracks qualifying out-of-pocket spending on covered Part D drugs.
  • Payments by the enrollee and certain payments made on the enrollee's behalf may count.
  • Premiums, non-covered drugs, and costs outside Part D rules generally do not count.
  • TrOOP matters because it affects when an enrollee reaches the annual out-of-pocket threshold.

How TrOOP Works

Medicare Part D plans track qualifying prescription drug spending during the year. When covered drug costs paid by the enrollee or certain eligible third parties count toward TrOOP, they move the enrollee closer to the annual out-of-pocket threshold.

The exact threshold and benefit structure can change by year. The concept stays the same: TrOOP determines which drug costs count toward the Medicare Part D out-of-pocket calculation.

What May Count Toward TrOOP

Cost or Payment

Typical Treatment

Deductible paid for covered Part D drugs

May count

Copays or coinsurance for covered Part D drugs

May count

Payments by certain assistance programs

May count under Medicare rules

Monthly Part D premiums

Generally do not count

Non-covered drugs

Generally do not count

Part D Cost Planning

TrOOP can affect how someone plans for expensive prescriptions. A person with high drug costs may reach the out-of-pocket threshold faster than someone with low-cost generics. But the calculation depends on plan coverage, formulary status, pharmacy network, assistance programs, and current-year Medicare rules.

Because Part D rules change, beneficiaries should review the current Medicare plan materials, formulary, and pharmacy cost estimates instead of relying on a prior year's threshold.

What Can Create Confusion

TrOOP can be confusing because several dollar amounts may appear in Part D materials: premiums, deductible, retail drug cost, plan-paid amounts, pharmacy payments, and member cost sharing. Only some of those amounts move the TrOOP calculation. A beneficiary may spend money during the year and still find that not all of it counts toward the Part D out-of-pocket threshold.

The Bottom Line

TrOOP is the Medicare Part D measure of qualifying prescription drug out-of-pocket spending. It helps determine when a beneficiary reaches the annual Part D out-of-pocket threshold, but not every health cost counts.

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