When a Natural Health Product (NHP) batch fails quality testing, manufacturers and importers must investigate the result, assess its potential impact on product safety and quality, and determine whether the batch meets Canadian regulatory requirements. A failed test, commonly referred to as an out-of-specification (OOS) result, does not automatically mean the product must be destroyed. However, the affected batch cannot be released for sale unless the investigation establishes an acceptable basis for release.
Under Canada’s Natural Health Products Regulations, finished products must comply with established specifications and receive approval from a qualified Quality Assurance Person (QAP) before sale. Health Canada’s Good Manufacturing Practices Guide for Natural Health Products (GUI-0158), Version 4, implemented March 4, 2026, provides detailed expectations for investigating OOS results, evaluating affected batches, managing corrective and preventive actions (CAPA), and maintaining appropriate documentation.
Where testing identifies a problem after a product has entered the Canadian market, the investigation may also require assessment of previously distributed lots, examination of retained batch samples, and consideration of market actions or product recalls.
For NHP manufacturers, importers and distributors, an effective response to failed quality testing depends on documented procedures, scientifically justified investigations and appropriate QAP oversight. Understanding these requirements is essential to preventing non-compliant products from reaching consumers and demonstrating ongoing GMP compliance.
A batch failure occurs when testing or examination identifies a result that does not meet an established product specification or acceptance criterion. Under Section 44 of the Natural Health Products Regulations, NHPs available for sale must comply with the specifications established for the product, including requirements relating to purity, medicinal ingredient identity and quantity, and applicable potency.
Quality testing may identify deficiencies involving medicinal ingredient content, microbial contamination, chemical contaminants, product identity or other attributes relevant to the finished product’s specifications. A failure may arise during routine finished-product testing, stability studies, investigations of consumer complaints or testing of previously retained batch samples.
For example, an NHP containing a standardized botanical extract may fail testing because the measured quantity of a medicinal ingredient falls outside the established acceptance range. Alternatively, a finished product may exceed an applicable microbial limit, raising concerns about manufacturing controls, contamination or storage conditions.
Health Canada’s NHP GMP Guide (GUI-0158) classifies an out-of-specification result as a type of deviation requiring appropriate investigation. The organization must determine whether the result reflects a laboratory error, a manufacturing or processing deficiency, product deterioration or another issue affecting quality.
Importantly, the initial test result does not independently establish the cause of the failure. An investigation must evaluate the available evidence before a decision can be made concerning product release, rejection or further corrective action.
When an NHP batch produces an OOS result, the organization must prevent the affected material or product from being released while the result is investigated. Health Canada’s GMP guidance identifies quarantine, documentation and quality assessment as important controls for managing potentially non-compliant products.
The first priority is to ensure that the affected batch is appropriately identified and controlled. This may involve physically segregating the product, restricting its movement within an inventory system or applying other documented quarantine measures that prevent unintended distribution.
For example, if finished-product testing identifies an unacceptable microbial result, the affected batch should remain under quarantine while the laboratory data, manufacturing records and other relevant information are reviewed. The organization should also consider whether other lots manufactured under similar conditions may be affected.
The investigation must be conducted according to an established Standard Operating Procedure (SOP), with the QAP responsible for overseeing the assessment and determining whether additional controls are necessary.
Health Canada’s guidance emphasizes that a product should not be released until the organization has confirmed that the deviation does not adversely affect its safety, efficacy or quality. This requires an evidence-based assessment rather than relying on an assumption that the original test result was incorrect.
An OOS investigation must establish the likely cause of the failure and determine whether the affected product meets applicable quality requirements. Health Canada’s GUI-0158 quality assurance guidance describes the importance of reviewing laboratory data, manufacturing processes, equipment, materials and other factors that may have contributed to the result.
The initial investigation should determine whether the OOS result could have arisen from an identifiable laboratory error. This assessment may involve reviewing analytical procedures, sample preparation, instrument performance, calibration records, calculations, reference standards and laboratory documentation.
For example, an incorrect dilution calculation or documented instrument malfunction may explain an unexpected analytical result. Where a laboratory error is clearly established and supported by appropriate evidence, the original result may be invalidated and testing repeated according to an approved procedure.
However, a result cannot be dismissed simply because it differs from historical data or because a subsequent test produces a passing result. The investigation must establish a scientifically justified reason for invalidating the original result.
Where no identifiable laboratory error is found, the investigation must extend to manufacturing processes and other factors that could have affected the product.
A manufacturing investigation examines whether deficiencies in materials, equipment, procedures or processing conditions contributed to the OOS result. The QAP and relevant technical personnel may review batch records, production parameters, raw material information, equipment logs, environmental controls and previous deviations.
For example, a product that fails medicinal ingredient content testing may require investigation of ingredient weighing, blending procedures, material uniformity or manufacturing controls. A microbial failure may require examination of sanitation procedures, environmental conditions, equipment cleaning and contamination controls.
The investigation should also consider whether similar issues could affect other batches manufactured using the same materials, equipment or processes.
Health Canada’s guidance recommends evaluating the scope and severity of deviations according to their potential impact on product safety, efficacy and quality. This assessment informs the urgency of the investigation and whether additional controls, corrective actions or market measures are necessary.
Retesting may be appropriate during an OOS investigation, but it must be scientifically justified and performed under an approved procedure. Health Canada’s GMP guidance requires the QAP to approve retesting or resampling in advance, including the number of tests to be performed.
Retesting generally involves additional analysis of the original sample, while resampling involves obtaining another sample from the batch. The distinction matters because a new sample may introduce additional variability or fail to represent the material originally tested.
For example, where an analytical investigation identifies a documented laboratory error, repeat testing may help establish the correct result. Where no such error is identified, retesting alone does not resolve the underlying quality concern.
Health Canada specifically cautions against repeatedly testing or sampling until a passing result is obtained, a practice commonly described as testing into compliance. The guidance also states that averaging compliant and OOS results is not an appropriate means of resolving a failure.
All valid results, including suspect and passing results, must be considered when determining whether a batch can be released. The QAP must ensure that the investigation and any additional testing provide sufficient evidence to support the final quality decision.
The QAP is responsible for overseeing the quality decisions associated with an OOS investigation and ensuring that the affected product is appropriately controlled. Under Section 51 of the Natural Health Products Regulations, each batch must receive QAP approval before it is made available for sale.
Health Canada’s GUI-0158 guidance describes QAP responsibilities that include evaluating deviations, investigating OOS results, approving appropriate retesting, assessing affected batches and determining whether products should be released, rejected or otherwise controlled.
For example, when an imported NHP fails finished-product testing, the Canadian importer’s QAP may need to review the foreign manufacturer’s investigation, assess additional laboratory results and determine whether the evidence supports release under Canadian requirements.
The QAP must also evaluate whether the failure indicates a broader quality system deficiency requiring corrective action. This may involve reviewing supplier controls, testing procedures, manufacturing processes or documentation practices.
The independence of the quality function is particularly important when commercial considerations create pressure to release delayed inventory. Health Canada’s guidance emphasizes that quality decisions should be made independently of production, sales, marketing and other areas where conflicts of interest may arise.
For a detailed discussion of the role, see dicentra’s companion article, What Does a Quality Assurance Person Do for Natural Health Products?
When an investigation confirms that a batch does not meet applicable specifications, the organization must determine an appropriate disposition. A batch that remains non-compliant cannot be released for sale merely because the failure creates a commercial or logistical difficulty.
Depending on the nature of the failure, the product may require rejection, destruction or another disposition permitted under applicable requirements and approved procedures. In some circumstances, reprocessing or reworking may be considered, provided the activity is scientifically justified, appropriately controlled and approved through the quality system.
For example, a manufacturing deviation involving an incomplete processing step may require evaluation of whether an approved corrective process can produce a compliant finished product. By contrast, a product with an unresolved contamination issue may not be suitable for recovery and may require destruction.
The QAP must assess the potential impact of any proposed action on product safety, efficacy and quality. Reprocessed or reworked products must still meet applicable specifications and receive the required quality approval before release.
Health Canada’s GMP guidance requires organizations to document deviations, investigations, disposition decisions and related corrective actions. These records provide evidence that the organization identified the failure, evaluated its consequences and prevented non-compliant products from being released.
A failed retention sample presents a different compliance concern because the original batch may already have been released and distributed. Retention samples are representative finished-product samples maintained to support subsequent testing, identification and investigation of quality issues.
Section 61 of the Natural Health Products Regulations allows Health Canada to request samples of a lot or batch already made available for sale where the Minister has reasonable grounds to believe that the product may cause injury to a purchaser or consumer.
Health Canada’s GUI-0158, Section 6.13 — Lot or Batch Samples explains that retained samples may be used to investigate quality complaints, product licence compliance, labelling concerns and adverse reaction reports.
For example, a consumer complaint concerning product deterioration may prompt the manufacturer or importer to test a retained sample from the affected lot. If the sample fails an established specification, the investigation must determine whether the failure reflects a broader problem affecting products already distributed to Canadian consumers.
The investigation may need to consider product stability, storage conditions, manufacturing records, distribution history and the possibility that other lots are affected. Depending on the findings, the organization may need to implement market controls or initiate a recall.
Health Canada’s GMP guidance requires manufacturers, importers and distributors to maintain representative finished-product retention samples under documented procedures. These samples must be sufficient to support duplicate testing against the finished-product specifications and product licence requirements.
Samples must be retained for at least one year after product expiry in their original packaging and stored in a temperature- and humidity-monitored area under the labelled storage conditions, consistent with the product licence. Where multiple containers are needed for duplicate testing, Health Canada permits containers of the same material and construction, supported by documented evidence, with at least one bearing the Canadian market label. Where a batch undergoes multiple packaging or labelling operations, representative samples must be retained from the relevant operations.
For example, an NHP manufactured as one bulk batch but packaged through two separate packaging operations should have appropriate retention samples representing each operation. This allows subsequent investigations to evaluate potential differences in packaging, labelling or other activities affecting the finished product.
Where samples are stored at another facility, including a foreign site where necessary, the arrangement must be supported by an appropriate written quality agreement. Health Canada’s guidance also expects samples to remain accessible within a reasonable timeframe, giving 72 hours as an example.
Retention samples must not be confused with stability samples. Stability samples are collected for scheduled testing intended to support product shelf life, while retention samples are maintained separately for identification, investigation and potential regulatory examination.
Health Canada has authority under Section 61 to request samples of NHPs already made available for sale when there are reasonable grounds to believe that a lot or batch may result in injury to consumers.
The sample must be sufficient to determine whether the product complies with its established specifications. Section 61 also provides that the Minister cannot require a sample under this provision once more than one year has elapsed after the product’s expiry date.
For example, where Health Canada receives information suggesting that a particular lot may contain an unacceptable contaminant, it may request an appropriate sample from the manufacturer, importer or distributor for examination.
The organization must be able to identify and retrieve the relevant retention samples and provide supporting documentation. This makes sample traceability, storage conditions, retention records and quality agreements important elements of inspection readiness.
Health Canada’s GMP Guide, Section 6.13 identifies sampling procedures, retention records and documented storage arrangements as examples of evidence organizations should maintain to demonstrate compliance.
A failed batch does not automatically require a product recall. The need for a recall depends on whether affected products have entered the market, the nature of the non-compliance and the potential risk to consumers.
Where a batch fails testing before release and remains under effective quarantine, the organization may be able to resolve the issue through investigation and appropriate product disposition without a market recall.
However, where testing identifies a quality defect in products already distributed, the organization must assess the potential impact on consumers and determine whether a recall or another market action is necessary.
For example, a retained sample that fails microbial specifications may indicate that distributed products could present a health risk. The investigation may require examination of other lots, distribution records, complaints and the circumstances surrounding the original product release.
Under Section 62 of the Natural Health Products Regulations, a manufacturer, importer or distributor that initiates an NHP recall must provide the required information to Health Canada within three days after commencing the recall.
Health Canada’s Recall Policy for Health Products (POL-0016) and Drug, Natural Health Product and Biocide Recall Guide (GUI-0039) provide additional direction on recall assessment, classification, procedures and reporting.
Organizations should therefore ensure that their quality systems allow them to trace affected lots, identify distributed quantities, communicate with relevant parties and implement recall procedures when necessary.
An OOS investigation should not end with determining whether the affected batch can be released. Where the investigation identifies a quality system deficiency, the organization must consider whether corrective and preventive actions are necessary to address the cause and reduce the likelihood of recurrence.
Health Canada’s GUI-0158 guidance on CAPA and quality risk management describes a structured approach involving problem identification, documentation, root-cause investigation, corrective action, implementation and effectiveness monitoring.
For example, repeated failures involving inconsistent medicinal ingredient content may indicate a deficiency in blending procedures, equipment performance or supplier controls. Correcting the immediate batch issue may not be sufficient if the underlying cause remains unresolved.
A CAPA plan may therefore require revisions to manufacturing procedures, additional personnel training, supplier qualification activities, equipment adjustments or enhanced process monitoring.
The QAP must ensure that appropriate actions are documented and that their effectiveness is evaluated. The investigation should also consider whether similar deficiencies could affect other products or processes.
For importers, CAPA may involve foreign manufacturers or testing laboratories. Although corrective activities may be performed outside Canada, the Canadian importer remains responsible for maintaining appropriate oversight of the products it imports.
Reducing the likelihood of OOS results requires a quality system capable of identifying and controlling risks throughout manufacturing, testing, importation and distribution. Finished-product testing is an important control, but it cannot substitute for appropriate procedures and quality oversight during earlier stages of production.
For manufacturers, effective controls may include qualified suppliers, approved raw materials, suitable manufacturing procedures, equipment maintenance, validated or otherwise suitable analytical methods, personnel training and appropriate environmental controls.
For importers, additional attention is required to ensure that foreign manufacturing activities are supported by acceptable GMP evidence and that imported products meet Canadian specifications before release.
For example, an importer that relies on a foreign manufacturer’s Certificate of Analysis must ensure that the testing performed addresses the applicable Canadian specifications. Where additional testing is required, arrangements should be established before commercial importation rather than after a batch arrives in Canada.
Organizations should also evaluate trends involving deviations, complaints, OOS results and stability data. Identifying recurring issues early can help prevent isolated quality failures from developing into broader compliance concerns.
Understanding how to investigate failed batch testing, manage out-of-specification results and document corrective actions is an important part of maintaining GMP compliance. dicentra’s Natural Health Product GMP Training provides practical instruction based on Health Canada’s latest GMP guidance, including the requirements governing quality assurance, product specifications, testing, stability, records and lot or batch samples.
Designed for current and prospective Site Licence holders, Quality Assurance Persons (QAPs) and personnel involved in NHP operations, the online course covers the broader GMP framework and its application to manufacturing, importation and distribution. Participants who successfully complete the training and assessment receive a certificate with a unique serial ID, which can be maintained as part of their organization’s training records.
When an NHP batch fails quality testing, identifying the cause and determining an appropriate corrective action may require specialized regulatory and technical expertise. With more than two decades of experience, dicentra supports manufacturers, importers and distributors with GMP compliance assessments, deviation and OOS investigations, corrective and preventive actions (CAPA), quality system development and inspection readiness.
For companies importing NHPs into Canada, dicentra also offers NHP Importation Services through its established Canadian Site Licence. These services include foreign-site GMP assessments, product documentation review, QAP oversight and finished-product release for eligible products, helping importers meet their Canadian quality assurance obligations.
Whether you’re addressing a failed batch, investigating an out-of-specification result orstrengthening your quality assurance procedures, dicentra can help. Contact our regulatory experts to discuss your GMP compliance challenges and determine the next steps for your organization.