Managing TB Reference Strains and ATCC Controls
A tuberculosis laboratory needs a controlled system for biological reference strains, quality control organisms and working stocks. These materials support method verification, media checks, identification procedures, antimicrobial susceptibility testing and staff competency assessment. Without clear ownership and traceability, a reliable control can become an unidentified vial with an uncertain passage history.
The system should define which strains are required, why each one is held, who may access them, how they are stored and when they must be replaced. It should also connect strain management with biosafety, purchasing, equipment monitoring, waste disposal, incident reporting and continual improvement.
For Australian laboratories, the design must work across metropolitan services in Sydney, Melbourne, Brisbane, Perth, Adelaide and regional sites with longer freight routes. A practical framework should fit local accreditation expectations, state and territory work health and safety requirements, supplier lead times and the temperature extremes that can affect transport and freezers.
Define The Purpose And Scope
Begin with a written procedure covering reference strains, ATCC controls, proficiency-testing material and any in-house working stocks. State whether the collection supports culture, microscopy, molecular testing, antimicrobial susceptibility testing, media quality control or training. A strain should have a documented purpose; retaining material “just in case” increases inventory, storage and biosafety burdens.
The scope should identify all locations where strains may be received, stored, prepared, used or discarded. This includes the main laboratory, a containment facility, a teaching area and any regional hub. Assign a technical owner, a deputy and an authorised user group. The quality manager should control the document, while the technical lead confirms that the selected organisms remain scientifically appropriate.
Map the procedure against the laboratory’s quality management system and the twelve Quality Systems Essentials. The GLI Quality Tool provides a useful structure for linking personnel, equipment, purchasing, documents, assessment and continual improvement rather than treating strain control as an isolated freezer task.
Select And Identify Each Strain
Create a master register before ordering material. Useful fields include organism name, strain designation, supplier, catalogue number, lot number, certificate details, date received, expiry or review date, storage location, biosafety classification, intended application and authorised disposal method. For an ATCC control, record the exact ATCC number rather than relying on a shortened local nickname.
Define acceptance checks at receipt. The responsible person should compare the consignment with the purchase order, inspect packaging, confirm temperature conditions where applicable and check that the certificate of analysis is present. Damaged, thawed, leaking or incorrectly labelled material should be quarantined and investigated before it enters the controlled collection.
Separate master stocks from working stocks. A master stock is opened as rarely as possible and preserved under validated conditions. Working aliquots are prepared from it for routine testing, reducing repeated thawing, contamination risk and passage drift. Each aliquot should carry a unique identifier linked to the master vial, preparation date, operator and calculated passage number.
Control Storage And Access
The storage map should identify the freezer, rack, box and position for every vial. Use a consistent naming convention, durable labels and an electronic or controlled paper backup. Labels should remain legible at the validated storage temperature and should not depend on ink that fades during condensation or repeated handling.
Monitor freezers with calibrated or verified temperature devices, alarm notifications and documented review. Set an escalation process for power failure, equipment breakdown or an excursion outside the approved range. In a regional Australian facility, a replacement freezer may not be available the same day, so the contingency plan should include backup capacity, dry ice arrangements and approved transport providers.
Restrict access according to competence and role. A sign-out record should capture the user, date, purpose, vial identifier and quantity removed. The laboratory should reconcile inventory at defined intervals and investigate missing, unreturned or unexpectedly depleted stocks. Access logs also support incident review and demonstrate control during an external assessment.
Use Controls In Routine Testing
Each test system should have acceptance criteria stating which control is used, the expected result and the action required when the result is unacceptable. For example, a control may assess growth, staining, extraction, amplification, target detection or susceptibility performance. Controls should be selected to challenge the method appropriately without creating unnecessary exposure or workload.
Avoid using a single control strain for every purpose. A strain suitable for media growth verification may not be appropriate for a molecular inhibition check or an antimicrobial susceptibility panel. The technical procedure should identify the control’s role, frequency of use and interpretation limits. Any change in lot, supplier, medium, instrument, reagent or method should trigger a documented review of control suitability.
Prepare aliquots in a controlled area using approved containment practices and equipment. Record preparation calculations, dilution details, operator competency and any verification results. If a working stock fails its acceptance test, place related aliquots on hold, assess potentially affected patient or quality-control results, and document the decision to release, replace or discard the material.
Review passage number and viability trends. Excessive subculturing can alter characteristics and weaken confidence in the control. Set a maximum number of passages or a defined replacement point, then return to the original reference material or obtain a new lot through an approved supplier.
Integrate Safety And Waste Controls
A strain register should show the risk assessment, containment requirement, personal protective equipment, spill response and decontamination method associated with each material. Staff need practical training in aerosol-generating steps, centrifuge safety, sealed rotor use, transport within the site and response to a dropped or leaking vial.
Australian laboratories should align the procedure with applicable state or territory work health and safety legislation, institutional biosafety rules and relevant laboratory safety standards such as AS/NZS 2243.3. Requirements may differ between jurisdictions, so the responsible officer should confirm local obligations rather than copying a procedure from another state. Importing or receiving biological material may also involve Biosecurity Act 2015 requirements, permits or supplier documentation.
Waste must be segregated at the point of generation and treated by a validated process. Define how unused stocks, contaminated consumables, cultures, spill materials and expired controls are rendered safe. The laboratory can use this practical guidance on TB waste disposal when documenting decontamination steps, verification and final disposal.
Document every exposure, spill, temperature excursion and suspected contamination event. A corrective action should address the immediate risk and the underlying cause, such as an overloaded freezer, unclear labelling, an unsuitable courier route or inadequate competency training.
Verify Performance And Improve The System
Set measurable indicators for the programme. Examples include the percentage of strains with complete certificates, temperature excursions per quarter, inventory reconciliation discrepancies, control failures, time taken to replace depleted stocks and staff competency completion. Review trends at quality meetings and record decisions, owners and due dates.
Before introducing a new strain or supplier, use change control. Compare certificates, verify the organism’s identity or expected performance where appropriate, confirm storage conditions and update procedures, risk assessments, training material and purchasing records. Keep obsolete versions of documents according to the retention policy so the laboratory can reconstruct what was authorised at the time.
Prepare evidence for internal audits and external reviews. Useful records include the master inventory, receipt checks, freezer charts, alarm tests, maintenance reports, preparation worksheets, usage logs, disposal records, deviation reports and corrective actions. The guide on WHO SLMTA assessment can help laboratories organise evidence around quality improvement and assessment readiness.
| Management Element | Minimum Control | Evidence To Retain |
|---|---|---|
| Selection | Approved strain list with a defined testing purpose | Technical review and authorisation |
| Receipt | Package, condition, identity and certificate checked | Receiving record and certificate |
| Storage | Mapped location, validated temperature and alarm response | Inventory, temperature logs and alarm tests |
| Access | Trained, authorised personnel only | Training records and usage log |
| Working Stocks | Linked aliquots with passage limits | Preparation worksheet and vial identifiers |
| Routine Use | Defined expected result and failure action | Quality-control records and investigations |
| Disposal | Approved decontamination and waste route | Disposal log and validation evidence |
| Review | Indicators, audits and corrective actions | Meeting minutes and improvement records |
A well-designed system makes every vial accountable from procurement to disposal. It protects staff, preserves the validity of test results and gives the laboratory confidence that an ATCC control is authentic, suitable and within its approved use period. Build the procedure into the GLI Quality Tool framework, assign ownership, test the contingency arrangements and audit the records regularly so reference strain management remains a working part of quality practice rather than a static document.