Pharmacy & Part D

PDE (prescription drug event)

~8 min readBy Pelica Health teamPublished August 28, 2026Updated August 28, 2026Reviewed by Catherine Zhao

Short answer

A Prescription Drug Event, or PDE, is the record a Medicare Part D sponsor sends CMS for every prescription a member fills. It is not the pharmacy claim itself. It is a summary of one adjudicated claim, listing the drug, the fill, the pharmacy and prescriber, and every dollar split by who paid it. CMS requires the initial PDE within 30 calendar days of the date the sponsor or its PBM received the claim, which is the first reason a PDC number built on PDE data sits behind the pharmacy counter.

What a PDE is

A Prescription Drug Event is the record a Part D sponsor submits to CMS for each prescription drug transaction covered under the benefit. Prescription drug plans and Medicare Advantage prescription drug plans both submit them, one PDE per adjudicated claim.

A PDE is not a copy of the NCPDP transaction the pharmacy sent. It is a summary written after the fact, once the plan or its PBM has adjudicated the claim and knows what everyone paid. That gap between adjudication and reporting is the whole story of PDE lag.

CMS uses accepted PDE data for two things that matter to a health plan: settling what the plan is owed for the coverage year, and calculating the Part D quality measures the plan is rated on.

30 days

Deadline for the initial PDE, counted from the date the sponsor or its PBM received the claim. 7 days for drugs selected for Medicare price negotiation.

90 days

Window for adjustments and deletions, and the interval at which a rejected PDE must be resubmitted until CMS accepts it.

Part D adherence measures built on PDE data: diabetes medications, RAS antagonists, and statins. All triple-weighted.

What is on a PDE record

The record layout runs to several dozen fields. They fall into four groups.

Who. Beneficiary identifier, contract and plan benefit package ID, the pharmacy's NPI as service provider, and the prescriber's NPI.
What was dispensed. Date of service, product service ID (the NDC), quantity dispensed, days supply, fill number, prescription service reference number, dispense as written code, and compound code.
What it cost. Ingredient cost paid, dispensing fee paid, sales tax, and the two gross drug cost fields that split the total at the out-of-pocket threshold: GDCB below it and GDCA above it.
Who paid. Patient pay amount, other true out-of-pocket amount, the low-income cost-sharing subsidy amount, and the plan-paid amounts.

The days supply and date of service fields are the two that drive every adherence measure. A wrong days supply does not fail any CMS edit and does not affect payment, and it silently moves a member's PDC.

How a PDE gets to CMS and back

The sponsor transmits PDE files through the Prescription Drug Front-End System, and they land in the Drug Data Processing System (DDPS). DDPS checks enrollment and eligibility, runs duplicate detection, then applies logic edits that compare fields on the record against each other. The detail cost fields have to sum to the payment fields, allowing for rounding.

Every submitted PDE comes back accepted or rejected, with an error code on the rejects. CMS also delivers monthly PDE reporting to sponsors, including an Immediately Actionable PDE errors report listing the records CMS expects the sponsor to correct and resubmit right away.

Rejects, adjustments, and the deadlines that govern them

42 CFR 423.325 sets four clocks, and they are the ones to know cold.

Record type	Deadline	Counted from
Initial PDE	30 calendar days	The date the sponsor, or a contracted first tier, downstream, or related entity, received the claim
Initial PDE for a selected drug	7 calendar days	Same. Claim receipt date is day zero, and the transmission date to the front-end system is the submission date
Adjustment or deletion	90 calendar days	Discovering, or being notified of, the issue that requires the change
Rejected PDE	At least every 90 calendar days	Receipt of the rejection, repeating until the record is accepted

The 7-day rule is the newest of the four. It applies to drugs selected under the Medicare Drug Price Negotiation Program, whose maximum fair prices took effect January 1, 2026 for the first ten Part D drugs. The tighter deadline exists so manufacturers can refund dispensing pharmacies quickly enough that pharmacies keep stocking the drugs.

A rejected PDE is worth more attention than it usually gets. The fill happened, the member has the drug, and the pharmacy was paid. But CMS has no record of it, so it does not count toward the member's true out-of-pocket total, does not enter the plan's reconciliation, and does not appear in the denominator or numerator of any adherence measure. A rejected PDE that nobody resubmits is a fill that, as far as CMS is concerned, never occurred.

Why PDC and adherence dashboards trail the pharmacy counter

The pharmacy learns the outcome of a claim in seconds. The PBM adjudicates in real time and tells the pharmacist what the member owes. CMS learns about the same fill considerably later, and four separate delays stack up.

The submission window. The sponsor has 30 days from claim receipt to send the initial PDE, and many send in scheduled batches rather than continuously.
DDPS processing. Records are edited on CMS's cycle, and the response comes back after that.
Rejects. A rejected record is not in the data at all until it is corrected and accepted, which the regulation allows to take another 90-day cycle, repeatedly.
Reversals and adjustments. A fill reported in week one can be reversed in week six. Adjustment and deletion records rewrite history, so a member's PDC for a period you already reported can move after you reported it.

The consequence is specific: the adherence number a plan reports internally off PBM data and the number CMS calculates from accepted PDEs will not match at any given moment, and the CMS number is the one that becomes a Star Rating. Teams that only watch the CMS-derived reports are working from a picture that is weeks old, which on a triple-weighted measure is the difference between an intervention that lands and one that arrives after the member has already missed the days.

The practical answer is to run interventions off pharmacy and PBM data in near real time and reconcile against PDE-derived reports, rather than waiting for the PDE view to tell you a member has slipped. By the time it does, the days are already gone.

PDE in payment reconciliation and DIR

Part D pays sponsors prospectively based on their bids, then settles up. After the coverage year closes, CMS reconciles those prospective payments against the plan's actual experience, and that experience is summarized on PDE records: reinsurance, the low-income cost-sharing subsidy, and risk corridors all run off accepted PDE data.

PDE dollars are point-of-sale dollars, so they do not tell the whole story. Compensation that changes hands after the sale, which CMS calls direct and indirect remuneration, is reported separately. Sponsors file DIR reports for a coverage year in June of the following year, and CMS factors that reporting into final payment. The two data sets have to agree, which is why a PDE with the wrong ingredient cost is a reconciliation problem long before anyone notices it is also a quality problem.

Common mistakes with PDE data

Counting the 30 days from the fill date. The clock runs from the date the sponsor or its PBM received the claim, not the date the member picked up the prescription.
Letting rejects sit for a full 90-day cycle. The regulation sets a floor of resubmitting at least every 90 days. Nothing stops you from fixing a reject the week it arrives, and the fills sitting in that reject queue are missing from your adherence measures the entire time.
Ignoring days supply accuracy. It clears every payment edit and it drives PDC directly.
Reconciling PDE to PBM data annually. Once the coverage year closes and reconciliation runs, a missing PDE is a payment you did not collect.
Waiting for PDE-derived reports to trigger outreach. Adherence is won in the days between fills, and the PDE view of those days arrives after they have passed.

How Pelica handles the PDE lag

Pelica's Pharmacy and Part D Copilot reads pharmacy and PBM fills as they land rather than waiting for the CMS-derived view, so the days-covered clock on every member is current. Members drift out of adherence gradually, and the copilot works the gap while there are still days left to recover: refill outreach, prescriber follow-up when the fill is not authorized, and escalation to a pharmacist when the barrier is clinical. Rejected and unadjusted PDEs are reconciled against the fills the plan can see, so a member is not counted as non-adherent because a record failed an edit. Customers hold 96%+ adherence on the triple-weighted measures.

Related terms

PDC is the measure calculated from these records and the reason days supply accuracy matters. Medication adherence covers the three triple-weighted Star measures built on PDE data. SUPD is the statin-use measure that reads the same fills, and MTM is the Part D program whose eligibility runs partly off drug spend visible in PDE data.

Sources

Frequently asked questions

Common questions about PDE records, submission deadlines, rejects, and the lag between a fill and an adherence number.

What is a PDE in Medicare Part D?

A Prescription Drug Event is the record a Part D sponsor submits to CMS for each prescription drug transaction covered under the benefit. It is not the pharmacy's NCPDP claim. It is a summary written after the plan or its PBM adjudicated that claim, carrying the drug, the fill, the pharmacy and prescriber, and every dollar broken out by who paid it. CMS uses accepted PDE data for Part D payment reconciliation and for the Part D quality measures.

When must a Part D sponsor submit a PDE?

Under 42 CFR 423.325, an initial PDE record is due within 30 calendar days of the date the sponsor, or a contracted first tier, downstream, or related entity, received the claim. For drugs selected under the Medicare Drug Price Negotiation Program the deadline is 7 calendar days. Adjustment and deletion records are due within 90 calendar days of discovering the issue, and rejected records must be resubmitted at least every 90 calendar days until CMS accepts them.

What happens when CMS rejects a PDE?

The fill still happened and the pharmacy was still paid, but CMS has no record of it. The transaction does not count toward the member's true out-of-pocket total, does not enter the plan's payment reconciliation, and does not appear in any adherence measure. The sponsor has to correct and resubmit, at least every 90 calendar days until the record is accepted, unless the claim was reversed or the record was submitted in error.

Why does my PDC number lag the pharmacy counter?

Four delays stack up. The sponsor has 30 days from claim receipt to submit the initial PDE and often submits in batches. CMS then edits the record on its own processing cycle. Rejected records are absent from the data until they are corrected and accepted, which the regulation allows to take another 90-day cycle. And reversals and adjustments rewrite history after the fact, so a member's PDC for a period you already reported can change later.

What is on a PDE record?

Roughly four groups of fields: the beneficiary and plan identifiers plus the pharmacy and prescriber NPIs; what was dispensed, including date of service, NDC, quantity, days supply, fill number, and dispense as written code; what it cost, including ingredient cost paid, dispensing fee, sales tax, and the gross drug cost fields split above and below the out-of-pocket threshold; and who paid, including patient pay amount, other true out-of-pocket amount, the low-income cost-sharing subsidy, and plan-paid amounts.

How is PDE data used in Part D payment reconciliation?

CMS pays Part D sponsors prospectively based on their bids and then settles up after the coverage year closes. Reinsurance, the low-income cost-sharing subsidy, and risk corridors are all calculated from accepted PDE records. Post point-of-sale compensation is reported separately as direct and indirect remuneration, with DIR reports for a coverage year due in June of the following year, and CMS factors that into final payment.

By the time a PDE-based report shows a member slipping, the days are already gone.

Pelica reads pharmacy and PBM fills as they land, keeps the days-covered clock current on every member, and works the gap while there is still time to recover it. Customers hold 96%+ adherence on the triple-weighted measures.

Book a Demo → See the Pharmacy & Part D copilot