What to do when a controlled drug stock balance does not match the register

When the physical controlled drug quantity and the recorded balance differ, the team needs a safe, documented route to verify the count, protect patients and stock, escalate an unresolved concern, correct records and prevent recurrence. This guide describes England healthcare and GP practice arrangements, but the local standard operating procedure governs an actual incident.

The first response is to preserve the facts

A shift handover or routine stock check finds a difference between the physical controlled drug quantity and the balance recorded in the register. Do not quietly rewrite the balance or assume theft. Secure the stock, preserve the register and promptly involve the person named in the local controlled drug procedure. Record the time, product, form, strength, batch where relevant, expected balance, actual count, who counted and any immediate patient care concern. A second competent person should verify the count when available. The team must investigate the discrepancy and escalate it if it cannot be explained.

NICE guideline NG46 recommends that organisations have a standard operating procedure for stock checks against the controlled drug register and for reporting and managing discrepancies. It says the frequency should reflect use, incidents and risk, with at least weekly checks suitable for most organisations but not a universal interval for every setting. The process should record checks, and two people should be present where possible. An unexpected difference is therefore an event that the procedure must manage, not a number to reconcile by guesswork.

The response has two parallel aims. One is medicines and patient safety, which is to confirm whether a dose was missed, duplicated, supplied incorrectly or administered without a complete record. The other is stock security, which is to determine whether medicine is misplaced, unrecorded, lost or potentially diverted. Do not let a purely accounting investigation delay clinical review where a patient may have been affected. Equally, do not make an unsupported allegation about a colleague from an unexplained count. Keep evidence secure and use a fair incident process.

Confirm the product and the count

Check that the physical stock and register line refer to the same preparation. A medicine may have different strengths, formulations, pack sizes or presentations with similar names. Count unopened containers, part-used containers and patient-specific stock according to the local procedure. Check whether a liquid’s apparent remaining volume differs from its expected running balance because of measurement or residual loss, and follow the relevant procedure rather than inventing a correction. Verify that the count was performed by authorised people with the cupboard or storage area controlled during the check.

Record the observed count before recounting so there is a trace of what triggered the investigation. A second count can reveal an arithmetic or selection error, but it should not erase the first finding. If stock is stored in more than one authorised location, check all locations, including doctors’ bags or satellite areas where the service policy permits them. A stock transfer may be physically complete but awaiting a register entry. The investigation must confirm the supporting record, not merely accept a verbal explanation.

The CQC GP controlled drugs guidance advises practices to keep running balances, check stock regularly and identify out-of-date stock. It says that when the actual and recorded levels differ and the discrepancy cannot be immediately resolved, an entry must be made in the controlled drug register and the NHS England lead controlled drugs accountable officer for the area informed. That is a specific England GP-practice route. A trust or independent hospital with its own accountable officer should follow its internal governance and current reporting arrangement.

If an item appears missing, avoid a chaotic search that destroys the chain of custody. Assign who will inspect storage, returns, waste, prescription or administration records and transfer paperwork. Note who had access and when, without treating access alone as evidence of misconduct. The goal is to establish the facts and protect stock. If theft is suspected, the accountable officer and security or police route may be involved under the local procedure. Do not wait for proof beyond doubt before escalating a serious unresolved concern.

Reconstruct the movement of stock

Review receipts, supplies, administrations, returns, transfers, wastage, destruction and corrections since the last verified balance. Match each movement to a dated record and, where required, signatures or electronic audit trails. Check whether a dose was prepared but not administered, whether a partial dose was discarded, whether a patient brought in their own medicine, and whether a supply went to another department. A register entry may be missing, duplicated, put on the wrong page or written for a different strength. Preserve each source document while comparing it.

A useful reconciliation table lists date and time, event type, quantity in or out, person or destination, supporting record, expected running balance and any unresolved difference. It helps separate arithmetic mistakes from an unexplained physical shortage. If one transaction explains the difference, record exactly which evidence supports the conclusion. Do not state “book error” without identifying the entry, correction and person who authorised it. If no transaction explains the gap, the investigation remains open.

For medicines given to patients, involve the clinical team. Review administration records to see whether a patient received the intended dose and whether a dose was documented against the right person and time. Keep patient-identifiable details in the clinical record and place only the necessary cross-reference in the stock investigation. A stock shortage may reflect a documentation failure with no direct patient harm, or it may reveal a serious medicines incident. The physical count alone cannot tell you which.

Look beyond the one cupboard if the pattern suggests a broader system problem. Repeated discrepancies at handover, an unusual number of corrections, incomplete waste witnessing or poor segregation of patient-owned stock may indicate a weak process. NICE recommends that audit procedures cover the person responsible, audit frequency and management of discrepancies. The incident should test whether those controls worked, not just whether the immediate balance can be made to agree.

Escalate an unexplained difference through the right route

The local controlled drug standard operating procedure should name the accountable person and escalation route. For an England GP practice, the CQC GP guidance says an unresolved discrepancy should be entered in the register and the NHS England lead controlled drugs accountable officer informed. NHS England regional controlled drugs guidance says controlled drug incidents should be reported to the accountable officer so risks can be mitigated and themes learned from. Organisations with their own CQC registered accountable officer use internal reporting and quarterly occurrence processes, while others use the regional route described there. Confirm the current local contact and portal at the time of the event.

The CQC controlled drugs accountable officer page says NHS trusts and independent hospitals in England must appoint a controlled drugs accountable officer. That role manages controlled drug governance within the organisation. A small clinic or social care provider may not have its own officer. The same response template cannot assign every organisation an internal accountable officer. Identify the provider’s status before publishing a reporting instruction or building a software workflow.

Other notifications depend on the facts. A suspected theft may need police involvement. A patient safety incident may need local incident reporting and, if criteria are met, a CQC statutory notification. Professional conduct concerns may require employer and regulator processes. Do not assume a stock discrepancy automatically meets every notification threshold, or that one report to the accountable officer satisfies all other duties. Document who assessed each route and why. If immediate risk exists, act before the full investigation is complete.

Escalation should preserve fairness and evidence. Record facts, not speculation about motive. Limit access to allegations and staff information. Keep original register entries intact and make any corrections through the approved method so an auditor can follow the history. A manager who rewrites a page to “make it balance” may destroy the very evidence needed to explain the event. If the difference is resolved by an arithmetic correction, record the correction, rationale, date and authorisation rather than hiding that a discrepancy occurred.

Protect the service while the investigation runs

Decide whether the affected stock can still be used safely and whether access should be restricted. The answer depends on the nature of the discrepancy. A missing entry for a verified administration is different from an unexplained shortage, compromised storage or suspected diversion. The pharmacy and clinical leads should decide what stock, if any, needs to be quarantined or independently checked, and how patients will receive necessary treatment. A blanket instruction to stop all controlled drug use can itself harm patients.

Check other preparations and storage points where a process failure could extend beyond one item. If a shift handover omitted several entries, the team may need a broader reconciliation. If a supplier delivery was recorded incorrectly, confirm the invoice, packaging and receipt. If an administration error is suspected, review the patient record and clinical consequences promptly. Each additional check should have a reason and an owner, because an indefinite audit of every cupboard can obscure the urgent question.

Make sure staff know the interim process. Who may access the cupboard? Is an extra witness required under local policy? Who approves new supplies? How are stock movements recorded while an investigation is open? The accountable officer or pharmacy lead may set temporary controls, but the service must keep legitimate treatment available. Record the start and end of any restriction. A dashboard warning is helpful only if the clinical team knows what it means today.

Resolve the balance without erasing the event

A resolved discrepancy needs a documented explanation and a correct current stock record. If a register entry was omitted, the authorised correction should identify the source transaction and preserve the chronology. If stock was found in another authorised location, record how it moved there and whether the transfer process failed. If product was lost or destroyed, record the evidence and required reporting. If the cause remains unknown, do not mark it resolved because the next delivery restores the physical quantity. A new stock receipt can make a total look correct while the original loss remains unexplained.

Closure should be reviewed by someone with the authority and competence required by the local procedure. They should confirm the original count, investigation scope, patient impact assessment, reporting, correction, current balance and prevention actions. If an accountable officer has been notified, record any advice and whether follow-up information was sent. If police or another body is involved, do not interfere with their investigation. The local incident record can contain a status such as “balance corrected, cause still under investigation” rather than forcing one final green label.

NICE NG46 supports risk-based stock checks and audits. After a discrepancy, review whether the checking frequency, two-person practice where possible, storage access, handover and training remain appropriate. A one-off arithmetic error may call for a focused correction and briefing. Repeated missing entries may require a process redesign, electronic audit controls or management oversight. Suspected diversion requires a different response. A useful close-out explains why the chosen action addresses the cause.

Worked example: an omitted administration entry

A clinic’s weekly check finds one ampoule fewer than the running balance. Two authorised staff recount and confirm the difference. The responsible clinician reviews the administration record and finds that a dose was given to a patient, but the controlled drug register entry was omitted during a busy emergency. The team verifies the patient record, amount used, any waste and the staff involved. It checks that the patient received the intended dose and that there was no duplicated administration. The register is corrected through the approved process with a dated explanation and authorisation. The event remains in the local incident log for learning.

The review finds that emergency use often separates administration and register completion. The clinic changes handover so a second person confirms the register is updated before stock is returned. It checks the next several stock balances to see whether the change worked. The outcome is not merely “count fixed”. The clinical and stock records now agree, and the process gap has a tested correction. If the initial discrepancy could not have been promptly explained, the practice would also follow the unresolved-discrepancy escalation route.

Worked example: unexplained shortage across a ward

A hospital ward finds that two packs are missing from a controlled drug cupboard. The recount confirms the shortage. The team secures the cupboard, records access and checks receipts, issue records, patient administration, returns and waste. No documented movement explains the difference. The ward informs pharmacy and its controlled drugs accountable officer under the internal procedure. Clinical leads check that patients have not missed treatment and arrange safe supplies while the inquiry continues. The accountable officer decides whether additional security, police, professional or statutory routes are needed based on the emerging facts.

The organisation does not accuse a named worker because they had access, and it does not wait for certainty before controlling stock and reporting the unresolved loss. The investigation identifies weaknesses in transfer records between pharmacy and ward, but that alone does not prove where the packs went. The event stays open until the factual account, reporting and prevention plan are reviewed. Future audits compare transfer records and physical balances at both ends of the handover.

FAQs

Sources

• NICE: NG46 controlled drugs recommendations
• CQC: GP mythbuster 28, management of controlled drugs
• CQC: controlled drugs accountable officers
• NHS England: regional accountable officer guidance
• CQC: reporting medicine-related incidents in adult social care

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