A controlled-substance count that does not match the log is one of two things: a bookkeeping error or a missing drug. The difference matters, but the investigation workflow is the same either way — and a DEA inspector will want to see that your practice treated the discrepancy as seriously as the regulation requires.

Public DEA actions and veterinary compliance consultants consistently identify controlled-substance recordkeeping and inventory reconciliation as high-risk inspection areas. CUBEX cites a DEA-related finding that 37% of inspected veterinary clinics had controlled-substance inventory discrepancies, while Titan Group's veterinary case analysis reported recordkeeping deficiencies in 94% of the practices it analyzed. Treat those figures as vendor and consultant benchmarks, not national prevalence data.

This article covers what to do when a count does not match the log: how to investigate, what to document, when to escalate, and what the DEA expects to see when they walk in unannounced.

What counts as a discrepancy

A discrepancy is any situation where the physical count of a controlled substance does not match what the daily-use log says should be on hand. This includes:

• A bottle or vial that contains fewer doses than the log records show were dispensed from it.
• A logged waste or destruction entry with no corresponding physical product.
• A receiving-log entry that does not match the wholesaler invoice or the product physically present.
• A biennial inventory count that does not reconcile against the opening balance plus additions minus dispensations, destructions, and losses.

The formula the DEA uses is straightforward:

Opening inventory + receiving-log entries − daily-use-log dispensations − destructions − losses = on-hand count

If the physical count does not match the right side of that equation, you have a discrepancy. The equation is from 21 CFR 1304.11, and it is the first thing a DEA Diversion Investigator will check.

Step 1: Isolate and verify

When a team member identifies a mismatch — whether during a routine count, a shift change, or a scheduled audit — the first action is to stop and preserve the current state.

Lock it down. Do not use, waste, or move any of the drug in question until the investigation is complete. Mark the bottle or log page so other team members know a count is in progress.

Recount. Have a second authorized person perform an independent count. For liquids, this means measuring volume (by syringe or by weight if your practice uses a scale-based reconciliation method). For tablets, count them. For injectable multi-dose vials, check the volume remaining against the log's running total.

Check the math. Pull the daily-use log for that specific drug and container. Verify every addition (receiving entries) and every subtraction (administration, dispensing, waste, destruction). A common source of false discrepancies is a transposition error or a dose that was administered but logged on the wrong date or wrong page.

Check the receiving log. Cross-reference the container's lot number and NDC against the wholesaler invoice. If the receiving log shows a delivery but the invoice shows a different quantity, the discrepancy may predate the container's arrival — which is a receiving-log problem, not a diversion problem.

Step 2: Review access

If the recount and math check do not resolve the gap, move to access review. The goal is to determine who had physical access to the drug during the period in question.

Pull the access record. If your practice uses a digital controlled-substance system (VetSnap, CUBEX, IDEXX controlled-drug management tools, or similar), export the access log for the drug and date range. If you use a paper log, review the signature entries — who checked the drug out, who witnessed, and when.

Review security footage if available. The DEA expects controlled substances to be stored in a "substantially constructed" locked cabinet or safe (21 CFR 1301.71). If your practice has a security camera covering the controlled-drug storage area, pull footage for the window between the last confirmed correct count and the discovery of the discrepancy.

Check key and access-code records. Who has a key or code? Has anyone been added or removed recently? Was a key lost? The DEA expects practices to limit access to the smallest number of authorized personnel necessary for operations. A VGP Veterinary compliance guide recommends maintaining a controlled-drug key authorization form that documents who has access and when access was granted or revoked.

Look for patterns. Is this the first discrepancy for this drug, or has this drug had repeated mismatches? Is the discrepancy tied to a specific shift, day of the week, or person? Titan Group DEA compliance specialists flag repeated discrepancies involving the same staff member, shift, or drug as a primary diversion red flag.

Step 3: Document the investigation

Every step of the investigation must be documented in writing. If the DEA arrives and asks, "What happened when you found the discrepancy?" you need a paper trail that shows the practice took it seriously.

Create a discrepancy investigation record that includes:

• Date and time the discrepancy was discovered.
• Drug name, strength, dosage form, lot number, and NDC.
• Expected count (from the log) and actual count (from the recount).
• Names of the team members who discovered the discrepancy and who performed the independent recount.
• Receiving-log reconciliation — did the invoice match?
• Access-log review — who accessed the drug between the last confirmed count and discovery?
• Root cause, if identified — e.g., "Dose administered at 14:30 on 3/5 was logged on the wrong drug page," or "No root cause identified after full review."
• Resolution — e.g., "Log corrected with explanation and supervisor signature," or "Unresolved — escalation initiated."
• Supervisor sign-off — the practice manager, medical director, or DEA registrant should review and co-sign the investigation record.

The University of Illinois Veterinary Teaching Hospital maintains a formal Controlled Substance Discrepancy Resolution SOP (SOP-005-CS, reviewed January 2026) that requires a standardized investigation form, an audit trail for every resolution, and a quarterly review of all discrepancies by a compliance officer. A general practice does not need this level of institutional formality, but the same principles apply: document the investigation, record the outcome, and make the records readily retrievable.

Step 4: Resolve or escalate

Not every discrepancy is reportable. A resolved discrepancy — one where the root cause is identified as a documentation error and the count is corrected — stays internal. But the resolution must be documented well enough that a DEA inspector could read it and agree that the explanation is plausible and supported.

When the discrepancy resolves

Common resolvable causes include:

• A dose was administered but logged on the wrong page or wrong drug.
• A waste entry was not recorded (drug was drawn up, not all was used, remainder was wasted but the waste was not logged).
• A receiving entry was recorded incorrectly (e.g., 10 vials were received but only 9 were logged).

In each case, correct the log with a dated, signed annotation explaining the error. Do not erase or overwrite — the DEA requires a clear audit trail.

When the discrepancy does not resolve

If the investigation does not identify a documentation or math error, you must assume the drug is unaccounted for. At this point the discrepancy becomes a potential theft or significant loss, and federal reporting obligations begin.

The reporting process is a two-step requirement established by a June 2023 DEA final rule (88 FR 40707):

Step 1 — One-business-day notification. The DEA registrant must notify the local DEA Field Division Office in writing (email or fax is acceptable) within one business day of discovering a theft or significant loss of any controlled substance. This is a preliminary notification — it does not need to be a complete investigation, but it does need to say what is missing and that an investigation is underway.

Step 2 — DEA Form 106 within 45 days. After the initial notification, the registrant has 45 calendar days to complete and submit DEA Form 106 electronically through the DEA Diversion Control Division's secure online portal. Paper submissions are no longer accepted as of July 24, 2023. The form requires detailed information: drug name, schedule, strength, quantity, NDC, lot number, and a narrative of the investigation. If the investigation is still ongoing at 45 days, submit the form with what you know and update it if more information becomes available.

You are not required to report every single missing tablet. The DEA uses the term "significant loss," and the agency has intentionally not defined a specific threshold — what is significant for a Schedule II opioid in a two-doctor practice may be different from what is significant for a Schedule V product. However, the safest approach is to report any unresolved discrepancy. A pattern of unreported small losses looks worse in an inspection than a pattern of promptly reported ones.

State requirements may be stricter. Many states have their own reporting timelines and forms. Texas, for example, requires veterinarians to comply with both federal and state controlled-substance recordkeeping rules (Texas Veterinary Board Rule 573.50). Check your state board's requirements before relying solely on the federal timeline.

Step 5: Corrective action

After the investigation — whether it resolved internally or was escalated — the practice should take corrective action to prevent recurrence. This is what distinguishes a compliant practice from one that the DEA will cite.

Process changes. If the discrepancy was caused by a logging error, change the workflow: require same-day logging (real-time is preferred), add a second-person verification step for Schedule II drugs, or switch from paper to a digital system that auto-populates fields and timestamps entries.

Training. If the discrepancy was caused by a training gap, document the retraining. The DEA expects practices to maintain a team training log documenting that all personnel with controlled-substance access have completed training upon hire and annually thereafter.

Access review. If the discrepancy suggests diversion, restrict access immediately. Remove the individual(s) from the authorized access list pending the outcome of the investigation. Document the change.

Audit cadence. If the discrepancy was caught late, increase the frequency of counts. The DEA mandates a biennial inventory (21 CFR 1304.11), but best practice — recommended by IDEXX, CUBEX, and multiple DEA compliance consultants — is weekly or even daily counts for high-use Schedule II drugs. CUBEX's cycle-counting guidance emphasizes that frequent, small counts catch problems when they are still small enough to investigate accurately.

The documents a DEA inspector will ask for

When a DEA Diversion Investigator arrives at your practice, they will typically request the following records:

1. DEA registration — current, not expired, address matching the practice location.
2. Biennial inventory — the most recent complete inventory of all controlled substances on hand, conducted on the inventory date required by 21 CFR 1304.11.
3. Receiving log and wholesaler invoices — for every Schedule II–V drug received since the last inventory. These must reconcile line by line.
4. Daily-use logs — separated by drug, showing every administration, dispensing, and waste event. Logs must be kept for at least two years and must be "readily retrievable" — meaning accessible and separated from non-controlled-drug records.
5. Destruction records — DEA Form 41 for reverse-distributor returns, or documented on-site destruction with two witnesses.
6. Any DEA Form 106 filings — theft and loss reports submitted since the last inspection.
7. Security documentation — evidence that controlled substances are stored in a substantially constructed, locked cabinet or safe, with access limited to authorized personnel.

If a discrepancy investigation record exists, the inspector will want to see it. A well-documented investigation — even one that ended in a Form 106 filing — demonstrates that the practice takes its obligations seriously. The absence of any investigation documentation is itself a citation risk.

Common investigation failures to avoid

Based on DEA enforcement actions and veterinary compliance consultants' reports, the most common mistakes practices make during discrepancy investigations are:

Waiting too long to investigate. The longer the gap between the discrepancy and the investigation, the harder it is to trace the cause. DEA inspectors will note whether the practice investigated promptly or let a mismatch sit in the log unresolved.

Investigating alone. A one-person investigation has no credibility. Always involve at least two authorized team members — the person who discovered the discrepancy and an independent reviewer.

Erasing or overwriting log entries. The DEA requires a clear audit trail. If a log entry was incorrect, draw a single line through it, write the correction, initial, and date it. Never use correction fluid or remove pages.

Failing to report an unresolved discrepancy. An unresolved discrepancy is an unaccounted-for controlled substance. The DEA does not distinguish between "we think it was a paperwork error but we are not sure" and "drugs are missing." If the count does not match and you cannot explain why, the reporting clock starts.

Not documenting the investigation itself. Even if the discrepancy resolves as a bookkeeping error, the investigation record should exist. Without it, an inspector sees only a log that was changed with no explanation.

Sources

• CUBEX, "DEA Controlled Substance Logging: A Guide for Veterinary Practices" — https://www.cubex.com/news/dea-controlled-substance-logging-a-guide-for-veterinary-practices
• CUBEX, "Veterinary DEA Controlled Substance Laws Explained" — https://www.cubex.com/news/understanding-dea-regulations-for-veterinary-controlled-substance-management
• University of Illinois Veterinary Teaching Hospital, "Controlled Substance Discrepancy Resolution SOP" (SOP-005-CS, reviewed January 2026) — https://answers.uillinois.edu/illinois.vetmedvth/132802
• Federal Register, "Reporting Theft or Significant Loss of Controlled Substances" (88 FR 40707, June 22, 2023) — https://www.federalregister.gov/documents/2023/06/22/2023-13085/reporting-theft-or-significant-loss-of-controlled-substances
• DEA, "Dedham Veterinarian Agrees to Pay $15,000 Settlement to Resolve Allegations of Inadequate Recordkeeping of Controlled Substances" (September 2022) — https://www.dea.gov/press-releases/2022/09/21/dedham-veterinarian-agrees-pay-15000-settlement-resolve-allegations
• Titan Group DEA, "How to Prevent Drug Diversion in Veterinary Practices: Compliance Strategies That Work" — https://titangroupdea.com/blog/how-to-prevent-drug-diversion-in-veterinary-practices-compliance-strategies-that-work
• Titan Group DEA, "Learn From Their Mistakes: Titan Case Analysis Is a Wake-Up Call to Veterinary Practices" — https://titangroupdea.com/blog/learn-from-their-mistakes-titan-case-analysis-is-a-wakeup-call-to-veterinary-practices
• Titan Group DEA, "The Role a Practice Manager Plays in Adhering to DEA Regulations" — https://titangroupdea.com/blog/the-role-a-practice-manager-plays-in-adhering-to-dea-regulations
• VGP Veterinary, "Paws, Don't Panic: Your Vet Clinic's Guide to DEA Compliance" — https://www.vgpvet.com/blog/paws-don%E2%80%99t-panic-your-vet-clinic%E2%80%99s-guide-dea-compliance
• IDEXX Software, "Controlled Drug Management Best Practices" — https://software.idexx.com/resources/blog/controlled-drug-management-best-practices
• Texas Veterinary Board, "Compliance Inspections" — https://veterinary.texas.gov/enforcement/compliance-inspections
• Missouri Department of Health and Senior Services, "Controlled Substance Guidelines" — https://health.mo.gov/safety/bndd/doc/vetguidelines.doc
• 21 CFR 1304.11 — Inventory Requirements
• 21 CFR 1304.21 — Records for Dispensers and Practitioners
• 21 CFR 1301.71 — Physical Security Controls for Practitioners