How to Conduct a Biennial Inventory Correctly

A biennial inventory is not a paperwork exercise to complete when a deadline approaches. It is a formal accountability record that establishes what controlled substances were on hand at a specific point in time. Knowing how to conduct a biennial inventory correctly helps a DEA registrant demonstrate control, identify unexplained discrepancies, and prevent small recordkeeping failures from becoming enforcement issues.

For pharmacies, hospitals, clinics, distributors, manufacturers, and other registrants, the quality of the inventory process matters as much as the completed document. An inventory that cannot be tied to purchasing, dispensing, administration, transfer, destruction, and return records provides limited protection during an inspection or investigation.

Start With the Federal Requirement and Your State Rules

Under federal requirements, every DEA registrant must take an initial inventory of controlled substances on hand when first engaging in controlled substance activities. After that, the registrant must take a new inventory at least every two years from the date of the prior inventory. This is commonly called the biennial inventory.

The biennial requirement is based on the date of the previous inventory rather than the calendar year. A new inventory must be taken at least every two years from the date of the previous inventory. For example, if the previous inventory was taken on June 15, the next inventory must be taken no later than two years from that date. Organizations with multiple DEA-registered locations should track the inventory date for each registration separately.

Federal rules establish a baseline. State boards of pharmacy, controlled substance authorities, licensing bodies, and organizational policies may require more frequent inventories, additional documentation, or specific inventory formats. When requirements differ, the more stringent applicable requirement generally controls. Compliance leaders should confirm the rules that apply to the registration, facility type, and jurisdiction before establishing the count process.

How to Conduct a Biennial Inventory Step by Step

A defensible inventory begins before anyone starts counting bottles. The responsible person should establish the inventory date, determine whether the count will be taken at the beginning or close of business, identify all controlled substance storage and use areas, and assign trained personnel to the process.

Define the exact inventory moment

The inventory must reflect controlled substances on hand at one identifiable point in time. The record should state the date and whether it was taken at the opening or close of business. Recording the actual time is also a sound control, particularly in hospitals, high-volume pharmacies, and facilities with around-the-clock operations.

The facility should control controlled substance movement during the count. Depending on operations, this may mean pausing transactions, separating stock received after the count point, documenting doses removed during the count, or conducting a documented cutoff reconciliation. The objective is straightforward: every unit on hand must belong to the inventory snapshot, and no transaction should blur that snapshot.

Identify every location where controlled substances may be held

A common failure is counting only the primary safe or vault. The inventory must include controlled substances wherever they are stored, maintained, or available for use under the registrant’s control. This can include will-call areas, automated dispensing cabinets, emergency kits, anesthesia work areas, satellite pharmacies, refrigerators, secured lockers, reverse-distribution staging areas, and quarantine locations.

The details depend on the operation. A retail pharmacy may need to account for filled prescriptions awaiting pickup and stock in a receiving area. A hospital may need an established method for reconciling cabinet inventory, pharmacy stock, operating room supplies, and controlled substances assigned to patient care areas. Inventory scope should be documented in advance so no area is omitted because staff assumed another department was responsible.

Count schedules accurately

Federal requirements distinguish between Schedule I and II controlled substances and Schedule III through V controlled substances. Schedule I and II substances require an actual physical count or measurement. For Schedule III, IV, and V substances, an estimated count is permitted if the container contains 1,000 or fewer dosage units. If a container contains more than 1,000 dosage units, an actual count is required.

Some organizations choose to perform an actual count of all controlled substances, including Schedule III through V. While this approach may require additional time and staffing, it can strengthen accountability and make discrepancy reviews more meaningful. The appropriate process will depend on the organization's volume, diversion risk, staffing, inventory systems, and applicable state requirements.

Do not rely solely on a perpetual inventory report, dispensing system balance, or automated cabinet screen. These records can support the physical inventory, but they do not replace it. A system balance is only as reliable as the transactions and adjustments entered into the system.

Record the required information clearly

The inventory record should clearly identify and document the controlled substances on hand at the time of the inventory. The record should include the date of the inventory, whether it was taken at the beginning or close of business, the registrant's name, address, and DEA registration number, and the controlled substances inventoried. For each controlled substance, identify the name, dosage form, strength, and quantity on hand. The inventory should also document the number of commercial containers and, as applicable, the number of dosage units or amount of substance contained in each container.

For liquid products and other substances that are not counted as individual dosage units, document the quantity using an appropriate unit of measure. For opened containers, the quantity should be determined and recorded in accordance with the applicable federal requirements. The inventory record should be sufficiently detailed that another reviewer can understand exactly what was counted without having to reconstruct the inventory from a separate system or worksheet.

DEA inventory records must be maintained for at least two years. In practice, longer retention may be appropriate when state law, organizational policy, litigation holds, or other applicable requirements call for it. Records should be organized and retrievable, not stored in a manner that makes prompt production difficult during an inspection.

Reconcile discrepancies before signing off

A count is the beginning of the review, not the end. Compare the physical inventory against expected balances generated from acquisition, dispensing, administration, transfer, return, wastage, and disposal records. Where the organization maintains perpetual inventory records or conducts periodic cycle counts, use those records to identify variance trends.

A discrepancy does not automatically establish diversion. It does, however, require a timely, documented, fact-based review. Possible causes include receiving errors, data-entry mistakes, unrecorded waste, delayed posting, incorrect package conversion, misplaced stock, or inappropriate access. The review should establish what happened, whether the explanation is supported by documentation, and what corrective action, if any, is necessary.

Unresolved losses or thefts may trigger [DEA reporting obligations] (https://www.veritascac.com/post/dea-loss-reporting-deadline-requirements-explained) and, depending on the circumstances, obligations to state regulators, law enforcement, insurers, or other parties. Organizations should not delay appropriate escalation while waiting for a discrepancy to become more significant. A defined decision-making process helps leadership determine the appropriate response, investigate promptly, and meet applicable reporting requirements.

Build Controls Around the Inventory Process

A well-designed inventory process should not depend on one employee's memory or individual recordkeeping practices. Establish clear responsibility for conducting the inventory, documenting the results, and reviewing any discrepancies or exceptions. Written procedures can help ensure the process is performed consistently, particularly when multiple employees or locations are involved.

For higher-risk operations, organizations may consider additional controls such as two-person counts for Schedule II substances, independent recounts when significant variances are identified, and inventory forms that are numbered or electronically protected from unauthorized alteration. These measures are not substitutes for the required inventory; they are additional controls that can strengthen accountability and help identify errors or irregularities.

The person conducting the inventory should complete and sign the inventory record, and an appropriate manager, pharmacist-in-charge, compliance leader, or other authorized individual may review the completed inventory and address identified exceptions.

Training should address more than the timing requirement. Staff should understand why opening-versus-closing designation matters, how to count partial containers, where controlled substances may be stored, how to document movement during the inventory period, and when to report a discrepancy. Clear, consistent instructions help reduce errors, particularly when staff turnover or cross-coverage is common.

Avoid the Shortcuts That Create Inspection Risk

Several shortcuts can weaken an otherwise valid inventory process. Backdating an inventory to address a missed deadline is a serious compliance concern. So is relying solely on a system-generated report without performing the required physical inventory, omitting controlled substances held in other locations under the registrant's control, or recording quantities without sufficient information to identify the specific controlled substance, strength, and dosage form.

Another common problem is treating the biennial inventory as separate from the organization's day-to-day controlled substance controls. A facility may complete an inventory while unresolved perpetual inventory variances, incomplete waste records, or weaknesses in access controls remain unaddressed. During an inspection, those conditions may prompt additional questions about the organization's ability to maintain accurate accountability for controlled substances.

The goal is not simply to complete the inventory by the required date. The process should produce an accurate, reliable record of the controlled substances under the registrant's control at a specific point in time.

A well-run biennial inventory gives an organization an opportunity to evaluate whether its controlled substance controls are working as intended. Use the inventory process to identify recordkeeping gaps, clarify responsibility, and strengthen accountability before a routine inspection, reported loss, or internal concern brings those issues to light.

The goal is more than completing a required count. The organization should be able to demonstrate what controlled substances were on hand at a specific point in time and explain any discrepancy identified during the process. When the inventory process reveals uncertainty or recurring problems, an independent compliance review can help identify gaps and strengthen the organization's overall controlled substance controls.