Preventing Reagent Expiration in TB Laboratory Inventory
Reagent expiration can interrupt tuberculosis testing, increase operating costs, and compromise confidence in laboratory results. The risk is especially high when supplies arrive in large shipments, testing volumes change, or storage conditions are difficult to maintain. A reliable inventory system helps the laboratory use materials in the right order and identify problems before they affect patient services.
Inventory control is more than counting boxes. It connects procurement, receiving, storage, testing schedules, quality control, documentation, and waste management. When these activities follow a consistent process, staff can see what is available, what must be used soon, and what should not be issued for testing.
The GLI Quality Tool provides a practical framework for organizing these controls within a broader laboratory quality management system. Its guidance can help TB laboratories adapt inventory practices to their staffing, equipment, workload, and available resources.
Build a reliable inventory picture
Begin with a complete inventory of reagents, kits, stains, culture media, molecular consumables, calibrators, controls, and other materials with a shelf life. Record the product name, manufacturer, catalogue or lot number, quantity, unit size, date received, expiry date, storage requirement, and current location. Include opened products, because their usable life may be shorter than the printed expiry date.
A spreadsheet may be sufficient for a small laboratory, while a stock management application can support larger services. The format matters less than the consistency of the records. Every item should have a clear status, such as available, quarantined, opened, expired, damaged, or reserved for a specific testing activity.
Assign responsibility for maintaining the register. One person may manage daily entries, but another staff member should periodically review the records. Separating routine recording from verification reduces unnoticed errors, such as duplicated entries or incorrect quantities.
Set stock levels around real use
A laboratory prevents waste more effectively when it orders according to consumption rather than habit. Review previous testing volumes, quality control use, repeat testing, referrals, seasonal changes, and expected campaigns. Calculate average monthly consumption for each important reagent and compare it with supplier lead time.
Set a minimum stock level that allows testing to continue while a new order is processed. A maximum level should prevent excessive purchasing, especially for products with short expiry periods or strict storage requirements. These limits should be reviewed when the laboratory introduces a new platform, loses testing capacity, or experiences a sustained change in demand.
Consider the smallest practical order quantity. Buying several large kits may appear economical, but savings disappear when unused materials expire. Procurement staff should receive information about current stock, upcoming expiries, and estimated consumption before placing an order.
Receive and store materials correctly
Inventory control begins when supplies arrive. Check the delivery against the purchase order and packing list before placing anything into storage. Inspect packaging for damage, verify the quantity and lot number, and confirm that the remaining shelf life is acceptable for the laboratory’s expected rate of use.
Temperature-sensitive reagents require particular attention. Record the condition of cold-chain shipments when applicable, document delivery temperatures, and quarantine items if transport conditions are uncertain. Do not mix newly received materials with active stock until acceptance checks are complete.
Storage areas should be clean, organized, secure, and easy to inspect. Separate reagents from chemicals or specimens that could cause contamination or damage. Keep materials off the floor, avoid overcrowding refrigerators, and label shelves or bins. A visible location system reduces the time staff spend searching and makes expiry checks more dependable.
Use expiry dates to guide daily issue
The first-expiry-first-out method is a simple way to reduce losses. Place products with the earliest expiry date at the front and newer stock behind them. This system should be adjusted when a product has a shorter in-use stability period after opening. Staff must know which date applies and should follow the manufacturer’s instructions.
Mark items that will expire soon with a clear, controlled label or electronic alert. The warning period should reflect consumption. A reagent used every day may need a 30-day alert, while a low-volume item may require three or six months of notice. Avoid handwritten changes that could obscure the original expiry date or create uncertainty about product status.
Issue materials in quantities that match planned work. Opening several kits at once can shorten their useful life and increase contamination or handling risks. Where manufacturer instructions allow, coordinate opening with scheduled testing and quality control activities.
| Inventory control | What to record or check | Suggested response |
|---|---|---|
| Receipt | Quantity, lot, expiry, packaging, transport condition | Accept, quarantine, or report the shipment |
| Storage | Temperature, location, security, separation | Correct conditions and document deviations |
| Daily issue | Item, lot, quantity, user, date | Apply first-expiry-first-out |
| Opened product | Opening date and in-use expiry | Label clearly and discard when stability ends |
| Monthly review | Near-expiry stock, consumption, discrepancies | Reallocate, adjust orders, or dispose safely |
| Disposal | Product, lot, quantity, reason, date | Follow biosafety and waste procedures |
Connect inventory records with testing records
Reagent traceability is essential for tuberculosis testing. Record the lot number of critical kits, reagents, controls, and media in worksheets, worksheets systems, or laboratory information systems as appropriate. If a quality control failure or unexpected result is investigated, these records help determine whether a reagent lot contributed to the problem.
A stock card or electronic record should be updated whenever material is received, issued, transferred, opened, discarded, or adjusted after a physical count. Record corrections transparently rather than deleting the original information. Differences between the recorded balance and the physical quantity should be investigated promptly.
Monthly reconciliation is a practical minimum for high-use items, while more frequent checks may be needed for expensive molecular kits or materials vulnerable to theft and misuse. A supervisor can compare inventory records with testing logs, procurement documents, and waste records to identify unusual consumption.
Make expiry review a routine quality activity
Expiry monitoring should be included in the laboratory calendar rather than treated as an occasional cleanup task. A designated staff member can complete a weekly visual check of active shelves and a more detailed monthly review of the full inventory. Findings should be documented, including actions taken and unresolved risks.
The phase one guidance is useful when a laboratory is establishing basic processes for documentation, equipment, supplies, and safe operations. Starting with a simple, controlled register is often more effective than introducing complex software without clear responsibilities or review practices.
Use these controls to make the process dependable:
- Keep a current inventory list for every reagent and consumable with an expiry date.
- Apply first-expiry-first-out when arranging and issuing stock.
- Set near-expiry alerts based on the product’s use rate and lead time.
- Compare physical quantities with records on a scheduled basis.
- Document quarantine, disposal, temperature excursions, and corrective actions.
Staff training should cover the meaning of expiry dates, opened-product stability, storage requirements, lot traceability, and procedures for damaged or questionable materials. New employees should demonstrate the process during orientation, and experienced staff should receive refresher training when procedures or products change.
Act before reagents become unusable
A near-expiry report is valuable only when it leads to a decision. First determine whether the product can be consumed safely before the expiry date. If demand is too low, consider transferring unopened stock to another approved laboratory, subject to national requirements, transport conditions, and traceability rules.
Do not extend an expiry date based on appearance, past experience, or pressure to reduce waste. Use only an authorized manufacturer extension or a formally approved national procedure. Expired, damaged, contaminated, or temperature-compromised materials should be clearly identified and removed from usable stock.
Disposal should follow laboratory biosafety and environmental requirements. Record the product, lot, quantity, reason for disposal, and date. These data can reveal recurring purchasing errors, unreliable suppliers, storage failures, or overestimated testing demand.
Use trends to improve procurement
Track the value and quantity of expired materials over time. Separate losses caused by over-ordering from those caused by poor storage, delivery delays, abrupt testing interruptions, or changes in diagnostic policy. A short review after each disposal cycle can identify preventable causes.
Procurement decisions should use actual consumption and expiry data. If one kit repeatedly expires while another is used quickly, adjust order quantities or delivery schedules. If a supplier routinely delivers stock with insufficient remaining shelf life, document the issue and include shelf-life requirements in future orders.
Inventory indicators can be discussed during quality meetings. Useful measures include stock-out events, expiry-related waste, inventory record accuracy, temperature excursions, and the percentage of critical items reviewed on schedule. These indicators turn reagent management into a measurable part of continual improvement.
A disciplined inventory process protects testing continuity and preserves scarce laboratory resources. Start with accurate records, clear storage, regular expiry checks, and decisions based on real consumption. Then integrate the findings into procurement, staff training, quality review, and corrective action. Visit the GLI resources and put a documented expiry-control routine into practice at the next inventory review.