Qualifying Visual Inspectors - A Practical Approach

PDA published a presentation on “Qualifying Visual Inspectors - The Benchmarking Process “ in December 2014 describes the objective and training requirements of visual inspectors.

Objective of the Manual Inspection Process is to detect and remove units of drug product with known defects in a reproducible manner hence it is crucial that the visual inspectors are trained and qualified such that they detect maximum no of defects and remove them.

It is ideal but sometimes impractical to expect that every inspector should detect 100% defects from a lot of millions of drug product units. For critical units detecting 100% defects may still be an expectation. For major or minor units qualifying the inspectors with most practical approach for detecting maximum no of defects may be something the regulators want to see during inspections and the practical approach obviously starts from selecting an inspector for manual visual inspection.

Selecting a visual inspector

Following are certain criteria to be kept in mind while selecting a visual inspector for manual inspection of drug products.


He should be aware of the importance of his task and the risk associated with defects in medicinal product.


The inspector should be able to perform repetitive work


Ability to learn and adapt new ideas


The inspector should have good observation skills and should also be patient


Pre-employment Health check

Pre-employment eye test – requirement > 90 % corrected

Training of Visual Inspectors

Eye inspections are performed prior to employment and at least once annually

Training of relevant SOPs and Work-Instructions

Introduction to defects using kits containing samples of different defects.

Learning individual defects using training kits and defect libraries

Basic qualification which should include mixing coded defects with good products and allow inspectors to remove defects.

Requalification once a year

Best inspectors offer 'tricks', methods, advice

Visual inspection under supervision and random checks or AQL checks are introduced.

During qualification the total practice is simulated including light intensity, fatigue levels of inspectors e.g. breaks of 5 minutes after every 30-45 minutes.

Expecting 100% detection of defects in a lot of millions of units may be impractical hence it is very difficult to decide acceptance criteria of visual inspector qualification. However for each inspector we can use qualification data to increase the possibility of detection by selecting inspectors who can detect maximum % of defects. Certain organizations also follow visual inspection twice so as to increase chances of detection. For example if the inspector is able to detect 80% of defects, the Ist level inspection may have chances to pass 20 % defects and re-inspection by same inspector will further reduce chances to pass only 4% defects.

Ideally for critical defects the person should be able to detect 100% defects

It is a good idea to incorporate statistical tools for visual inspectors qualification to detect repeatability and re-producibility of each inspector

Repeatability can be checked by giving the same set of coded defects mixed with good units repeatedly to same inspector and evaluating how closely the inspector agrees with his own results in all replicates.

Reproducibility indicates how closely an inspector agrees with the standard i.e. known number of defects.

If you are facing any challenges associated with Visual inspection and qualification of visual inspectors feel free to reach out Source consulting. This team help our customers to respond to FDA observations. For any queries on visual inspection, FDA expectations, compliance to regulatory inspection Source consulting team of highly experienced pharma professionals is always always available to help our clients.

For more details you may contact Sourceconsulting team.

27th Sept 2017