Differences between Verification, Calibration and Validation

Data Scrutiny is important before reporting

You have perhaps come across these terms in laboratory documents and wondered that they convey the same meaning so where is the need for different terminology. A little insight will help you understand the fine differences between them. Giving their concise definitions may suffice to gain a basic understanding but to help you get a clearer understanding I have attempted to offer clarity on the terms in context of routine activities in analytical laboratories as I believe that giving real life examples rather than recalling definitions serves the purpose better and makes you remember what is being conveyed longer.

Verification

In simple terms verification means confirming the authenticity of activities or data before communication to concerned parties. It is important that the results communicated by you are free from errors. Essentially verification comprises of multiple checks on supplies, samples and data before forwarding the results of your testing activities. Majority of the checks can be carried out by you but it is advised that independent assistance be taken for rechecking the data before submission.

Self Checks

• Correct sample was taken up for analysis.
• Sample description, analysis instructions were verified before start of analysis
• Equipment and glassware used was calibrated
• Recommended grades of chemicals from reliable sources were used
• Weight readings were correctly recorded and entered in calculations
• Recommended environmental conditions were maintained throughout the analysis.

Independent checks

It is strongly recommended that independent rechecking be carried out by a set of trained individuals before the analysis results are consolidated for report generation.

• Sample is analyzed as per the customer’s requirements. As an example in pharmaceutical analysis the tests are conducted in compliance with USP, BP, IP, etc.
• If sample information such as name, batch number, date of manufacture, date of expiry, sample source, etc are entered correctly or not in reports.
• Entered data matches with the data in the work sheets, for example, weight slips, spectra, chromatograms, etc
• If correct formulae have been used in calculations and a re-check on calculations.

All the steps covered above constitute verification before the results are entered for generation of the certificate of analysis.

Calibration

Calibration of laboratory instruments and glassware at stipulated intervals is mandatory for preserving the integrity of reported data. It helps in making suitable corrections on observed values .Such deviations result from normal wear and tear of instrument components and limitations due to useful life of instrument components. Calibration is carried out using a standard reference material. The observed values should lie within acceptable range. Periodic calibration is an absolute must for both highly sophisticated instruments as well as for routine instruments such as pH meters, moisture titrators, refractometers, analytical balances, etc. Volumetric glassware needs to be calibrated at least once before being put in routine use.

Validation

The term validation is used mainly with reference to test methods and analysis instruments. It is a documented process which establishes and assures that the method or instrument will provide consistent results within the prescribed acceptance criteria. Validation is different from calibration as it does not require comparison with a standard reference material. It is not require to be performed periodically as prescribed in standard operating procedures on calibration but it is sufficient to validate a method at the stage of adoption. A new instrument, on the other hand is validated at time of installation and commissioning or when important changes are made, for example, addition of a major accessory, relocation to a new premises or when analysis is required under a changed set of environmental conditions.

It is hoped that the concepts provided through routine daily laboratory activities will help you appreciate the differences between the terms Verification, Calibration and Validation which are the three cornerstones that define the parameters for sustained growth of laboratories.