What Companies Need to Know about GMP Measuring Instrument Calibration

Pharma manufacturing standards tend to be higher than many other sectors, and every process is heavily regulated by the Regulatory Authorities. According to pharmaceutical cGMP (current Good Manufacturing Practice) guidelines, pharma companies need to conduct regular instrument calibration as part of their validation and qualification activities.

What is Calibration and How Is It Different from Adjustment?

Calibration is the process of comparing measurements taken from an instrument under test against a known value or highly accurate standard, to determine the accuracy, reliability and traceability of the former. It is usually conducted under specific conditions (e.g. operating conditions), with procedures that can easily be reproduced.

Adjustment is the process of making changes to a faulty instrument so that it “reads true”, but this can invalidate a previous calibration. In case of any deviations, equipment needs to be re-calibrated after it’s adjusted or aligned, to ensure that incorrect measurements do not affect product quality or production efficiency.

Why is Calibration Important for Measuring Instruments?

The process of measurement is conducted to check whether something is accurate within a set of specified limits. The results are displayed as a numerical value and a standard unit, where the latter is a defined quantity based on a recognised system of metrology, e.g. Fahrenheit, inch, kilogram, bar, ounce, etc.

The standard unit may differ based on the system (metric or imperial, for instance), and devices used for this process include everything from simple gauges and thermometers to complex laser-based measuring systems, electronic weighing scales, etc. All these devices need to function perfectly, which is where calibration comes in.

Measuring instrument calibration helps pharmaceutical companies with Quality Assurance and cGMP compliance, in 3 main ways:

1. Traceability – Measurement results from a certain instrument need to be consistent with similar measurements taken from others, regardless of differences in the location, operators or even the instrument itself. This allows for greater control at any stage of the manufacturing, testing or validation process.

In order for these readings to be related to standard measurements, they need to follow a recognized national or international system of metrology. If a certain machine displays readings in “inches” or “oC”, the value of each “inch” or “oC” should be the same as any other machine using the same metrological system.

2. Accuracy – The accuracy of instrument readings affects the decision-making process for any production stage, and incorrect measurements can lead to quality, safety and compliance issues. Accuracy can be determined through “uncertainty”, a numerical estimate that is used to calculate the quality of any measurement.

This estimate is usually a spread of values that can reasonably be applied to a certain quantity. The stated uncertainty of a measurement allows it to be compared to others and reduces the risk of poor decisions made due to errors in measurement, as well as potential consequences of these decisions.

3. Reliability – As part of the validation programme for pharmaceutical products, the reliability of measuring instruments also needs to be established. Few devices have a higher accuracy than required for common tasks, and the cost, quality or complexity of the instrument rarely have an effect on its reliability.

By calibrating instruments regularly, it’s possible to maximize the reliability of their measurements by locating and correcting faults in time. Adjustments can be made before measurement errors affect the quality of the product, or are discovered during a regulatory inspection/internal audit.

Improving the Traceability of Measurements

According to pharmaceutical cGMP guidelines, companies need to show traceability for any measurement that determines the quality of the finished product. Traceability can be broken down into 3 main elements, which need to be followed during the measurement procedure:

  • A definition of how the quantity needs to be measured, based on recognized standards.
  • A measuring device that has been properly calibrated as per the manufacturer’s instructions.
  • An operator (or operators) properly trained in the use of the measuring device, procedure and standard.

Instrument calibration is an important maintenance requirement that must be performed by any business using measuring devices. Whether you outsource calibration services or choose to perform them in-house, a regular calibration schedule will help reduce risks and improve both quality and performance.

Guest Author Bio: Edward Simpson is a seasoned Calibration and Technical Engineer working for RS Calibration Inc. Edward has a knack for finding faults in machines and does not rest until they are rectified to perfection. He lives in Pleasanton, CA and can be contacted anytime for matters related to machines. He also invites people to visit his company www.rscal.com to learn more about the type of calibration work he does.

If you have any comments on this post then please feel free to comment.