GLI GLI Quality Tool
GLI Quality Tool — Version 2.0

Protocol design for TB laboratory stock rotation and expiry control

Reagent and consumable management is one of the quiet chores that keeps a tuberculosis laboratory running smoothly. When stock is well managed, specimens arrive in good condition, results are trustworthy, and clinicians act on them without delay. When it is poorly managed, the cracks show up as expired buffers, contaminated batches, or interrupted testing during a remote outreach.

A written protocol turns ad-hoc habits into a controlled process. Within the GLI Quality Tool framework, stock rotation and expiration management sit naturally inside the Equipment and Process Control Quality System Essential. The protocol becomes a living document that links day-to-day bench practice to the broader quality management system.

Australian laboratories carry additional obligations under NPAAC standards, NATA accreditation expectations, and the Therapeutic Goods Administration where applicable. A TB stock protocol needs to reflect those local requirements while remaining practical for the bench scientist in Broome, Cairns, or a regional hospital in the Top End.

The aim of this guide is to walk through the elements of a clear, usable protocol covering inventory mapping, risk-based categorisation, rotation mechanics, documentation, and staff training. It complements the phase-specific checklists already available through the GLI Quality Tool.

Regulatory and accreditation context in Australia

TB laboratories in Australia typically seek accreditation through the National Association of Testing Authorities against ISO 15189 and the National Pathology Accreditation Advisory Council requirements. Both expect demonstrable control of reagents and consumables, including lot numbers, receipt dates, expiry dates, and evidence of appropriate storage.

The Therapeutic Goods Administration oversees many in-vitro diagnostic products used in TB work, particularly those with a notified or registered status. Where reagents arrive under special access schemes, the documentation path lengthens, and the protocol should reflect that added layer.

State health frameworks add their own expectations. Queensland Health, WA Health, and the Northern Territory Department of Health each issue procedural directions that touch on pathology supply chains, and a well-designed protocol references local standard operating procedures rather than treating the laboratory as if it stands alone.

Mapping your reagent and consumable inventory

A protocol begins with an accurate picture of what the laboratory actually uses. List every reagent, medium, antibiotic supplement, stain, cartridge, and consumable that supports TB diagnostics, including smear microscopy, MGIT culture, Xpert MTB/RIF, and any line-probe assays performed on site. For each item, capture the manufacturer's recommended storage temperature, the shelf life as supplied, and any post-opening stability claims.

Group items by storage requirement and hazard class. Sodium hydroxide solutions, corrosive stains, and flammable solvents each have handling rules that affect storage layout, while cold-chain reagents, including some PCR mixes and certain fluorescent stains, require temperature monitoring with calibrated devices. Mapping these groupings early prevents the common error of storing a flammable solvent next to a heat-producing incubator or blocking airflow to a refrigeration unit.

In remote settings, the inventory map should also flag items that take longer to replenish. A laboratory relying on weekly freight into Kununurra or the Torres Strait needs different minimum stock levels than a metropolitan lab with same-day courier access. The map feeds directly into the ordering rules described in later sections, and it pairs neatly with the fluorescent microscopy training guide when inducting new staff.

Risk-based stock categorisation

Not every item carries the same consequence when it expires. Risk-based categorisation allows the laboratory to focus effort where it matters. Critical reagents are those whose failure would directly compromise a TB result: MGIT growth supplements, Xpert cartridges, primary culture media, and quality control strains. Their expiry dates demand the closest attention.

Semi-critical items include stains, buffers, and general consumables, where failure may produce ambiguous results rather than a complete failure but the impact on patient care is still meaningful. Non-critical items are general laboratory supplies such as disposable pipettes or cleaning agents, where expiry has a smaller effect on the diagnostic result.

Assign each category a review frequency, a minimum stock level, and a rotation rule. Critical reagents might warrant weekly checks and a one-month reserve, while non-critical items can be reviewed monthly. Documenting these thresholds removes guesswork that often plagues busy laboratories and gives locum or weekend staff a clear guide.

Storage conditions and the cold chain reality

Storage conditions are where many protocols become purely theoretical. Across Australia, ambient temperatures range from sub-zero in southern winters to sustained 35°C across northern summers. A protocol must spell out how the laboratory maintains manufacturer-specified storage conditions, including in facilities with limited climate control.

Refrigerators and freezers used for TB reagents need continuous temperature monitoring with a calibrated data logger or chart recorder. Records are reviewed at defined intervals, and excursions are investigated promptly. The protocol should describe what happens when a temperature is breached: who is notified, how the affected stock is quarantined, and when the supplier is contacted.

Ambient storage areas also need attention. Stains stored in direct sunlight degrade faster, and humidity in tropical zones can compromise packaging integrity. Where possible, store light-sensitive reagents in closed cabinets and use desiccants where appropriate. The protocol can specify storage locations by function rather than by person, which keeps things consistent during staff changes.

Rotation procedures and quarantine triggers

Stock rotation is the operational heart of the protocol. The principle is simple: items with the earliest expiry are used first, and any item approaching expiry is either consumed in routine work, redirected to a lower-volume site, or quarantined for assessment. The protocol should describe each of these actions clearly.

Define a quarantine trigger period, often three months before expiry for critical reagents and one month for semi-critical items. Quarantined stock is physically separated, ideally in a clearly labelled bay or shelf, and is not issued for patient testing. A short review meeting each month decides what to do with quarantined items: issue, transfer, or discard.

Disposal must follow local waste management regulations, particularly for chemical and biological waste. Sodium hydroxide, concentrated stains, and culture-positive material each have specific disposal pathways, and the protocol should reference the relevant Australian Standard and the laboratory's waste contractor arrangements so the reasoning is transparent to any auditor.

Documentation, records, and audit-ready evidence

A protocol is only as strong as the records it generates. The protocol must list the documents required for each stage: purchase orders, delivery receipts, temperature logs, expiry registers, quarantine records, and disposal certificates. Each record needs an owner, a storage location, and a retention period that aligns with NPAAC and jurisdictional requirements.

Electronic systems work well where available, but many Australian laboratories still keep paper registers at the bench. Either approach is acceptable provided data is captured consistently and can be retrieved quickly, and audit trails that link a reagent lot to a patient result are particularly valuable when investigating an unexpected finding.

Version control is often overlooked. The protocol itself should carry a version number, an approval date, and the names of those who reviewed and authorised it. Superseded versions are archived, not deleted, so the laboratory can demonstrate how its practice has evolved over time. A review cycle of one to two years keeps the document current without becoming a burden.

Training, competency, and continuous improvement

The final element of the protocol addresses people. New staff need a structured induction covering the receiving procedure, rotation rules, quarantine triggers, and documentation expectations. Refresher training keeps experienced staff current and is particularly important after a protocol revision or following an incident involving expired or compromised stock.

Competency assessments confirm that training has been absorbed. A short practical assessment, covering receipt of a delivery and update of the expiry register, is usually sufficient, and records of training and competency are kept in personnel files and referenced during annual performance reviews.

Continuous improvement closes the loop. The protocol should describe how the laboratory captures feedback from staff, audits, near-misses, and supplier performance, and that feedback feeds into the next revision. Embedding stock management within the wider quality system helps the laboratory mature, with each improvement cycle raising the bar slightly.

Practical recommendations for a robust stock protocol

Take the next step by mapping your current inventory against the categories described here, then draft a single-page rotation procedure your team can actually use. Walk it through with the bench scientists who will live with it every day, refine the wording, and lodge the final version with your quality manager. Once approved, schedule the first stock huddle within the fortnight and link the protocol to your training plan so new starters are inducted from day one.