Why you need a calibration program

Metrology is the scientific study of measurement.

If you make things, you need to calibrate the buildings, equipment, and processes that you use to make things.

If it moves or measures and doesn’t breathe, it might need calibration. Your calibration program identifies the critical items that need calibration, the items that are for information only, etc.

If you can’t measure it, you can’t calibrate it.


Once you decide what needs calibration, you need to determine what measurements you need to make. Your calibration program establishes the tolerances, the calibration interval, and the measurement data that you or your calibration service providers must generate for “it,” whether “it” is your buildings, your equipment, or your process(es).

Whether you do it yourself or have calibration service providers do it for you, your Quality Assurance group is ultimately responsible for your calibrations. If you use a service provider, use one that has current Good Manufacturing Practice (cGMP) experience.

You Might Need Verifications

Once you calibrate, you can perform verifications. Verifications are your in-process checks performed on the floor during the calibration interval to ensure that “it” is still in calibration. Not everything needs verification.

How Do I Decide if I Need Verifications?

Do a criticality assessment of your system to identify which things need verification and which do not. Your criticality assessment should take into account measurement systems that affect Quality Control data or customer requirements. How critical is the parameter, e.g., the temperature, mass/volume, pressure, etc., being measured? Suppose you have determined that the parameter in a step is critical to the quality attributes, perhaps even a Critical Control Point (CCP), of your product or process. In that case, you may want to design a verification for that step.

Calibration versus Verification

Calibration uses a reference standard at least four times, and usually ten times or more, accurate than the tolerance you set for whatever you are calibrating. This ratio of the accuracy of the standard to the working device is the total accuracy ratio or TAR. For example, if your process requires a ± 4 RPM for a mixer or centrifuge, then the reference standard needs to perform at a stated accuracy within ± 1 RPM.  Calibrations are done by members of your Metrology staff or your service provider who are adequately trained via the appropriate procedures.

Verification uses a working standard that is suitably accurate to show that the item you are verifying is within the tolerance that you set for it. You want the verification standard to be accurate, robust, easy to use, and give you a “go-no go” result in a short time so that you can get back to processing. Verifications are done by your production personnel on the floor in the plant and recorded on batch records or similar documentation.


    • Performed at regular intervals as defined in your Quality System
    • Performed for troubleshooting when a measurement is outside of expected operating readings
    • Calibration label on the device states the date of performance and the due date
    • Displays a legible calibration sticker traceable to documentation


    • Designed into the process and performed during manufacturing or periodically
    • Done before use to identify equipment operating outside of expected performance
    • Recorded in pre-operation or batch records
    • Part of the equipment logs, batch record, etc., for the equipment, process, etc.


You need a comprehensive program for calibration and verification of your facility, equipment, and process(es). When deciding how to incorporate equipment into your calibration program, criticality and risk assessments are best practices, especially surrounding attributes critical to quality.

PSC Biotech has years of experience in calibration programs, metrology, criticality analysis, risk assessment, process validation and can provide you with calibrated, validated equipment for your metrology needs. Contact us now! PSC Biotech®

If you found this material relevant, please take a moment to share how you manage calibration at your site(s): Metrology Survey

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