What's the Difference Between Calibration and Validation in the Lab?
Calibration and Validation
Calibration and validation are two important processes that are often misunderstood and used interchangeably in the lab. However, they serve different purposes and should not be confused with one another.
Calibration is the process of comparing the measured value of a device or sensor to a calibrated standard in order to determine its accuracy. Equipment manufacturers may test and calibrate equipment on the assembly line and provide a calibration certificate, but this certificate is only valuable if the sensors used can be traced back to a reliable standard such as the National Institute of Standards and Technology (NIST). Without traceability, it is difficult to trust the displayed values and overall operational quality of a device, and ensure that it is fit for purpose.
On the other hand, validation is the process of ensuring that that piece of equipment is capable of performing according to the specified requirements for that equipment. Even if a device or sensor is calibrated and producing accurate measurements, this does not automatically mean that the equipment or room is fit for purpose. Validation however can apply to software, SOP’s or processes. Validation also takes into account other factors, such as the behavior of the system, equipment or environment under different loads, power failures, door openings and myriad other factors.
Let’s dive into these two processes below.
Calibration of Equipment: Accuracy For Your Lab
Proper calibration of lab equipment and sensors is crucial for the accuracy and reliability of results, as well as the safety of the users. If a device is not calibrated correctly, it can lead to incorrect data and decision-making, which can have serious consequences, particularly when dealing with sensitive materials such as blood or medicine. For example, if the temperature of a fridge storing blood is not accurately measured, it can put the lives of patients at risk if the blood is not stored properly.
Calibration is an essential part of any quality management system, including ISO, FDA, CAP, CLIA, and GMP. Ensuring that your equipment is properly calibrated and meets regulatory standards is necessary for the smooth operation of a lab or facility and for maintaining the accuracy and reliability of results. Properly calibrated equipment is also crucial for meeting regulatory requirements and maintaining compliance. Properly calibrated hardware, software and processes will ultimately lead to better science with more predictable results.
While some labs may choose to send their equipment or sensors to be calibrated by a factory, this option can raise concerns about traceability. A factory calibration certificate may not be considered official unless it includes NIST traceability, which verifies the accuracy of the calibration. Without NIST traceability, it may be difficult to determine the value of the factory calibration certificate. It is important to ensure that the calibration of lab equipment can be traced back to a reliable and accurate source in order to maintain the accuracy and reliability of results.
There are two options for calibrating lab equipment. One option is for users to calibrate their own devices using a NIST-calibrated device, which allows for daily control and basic traceability. However, it is important to note that the calibration process can be complex and requires a thorough understanding of the processes. Without proper oversight, the uncertainty of this process may be unknown and if the sensors are calibrated incorrectly, this may lead to even more inaccuracies.
The second option is to hire a professional (e.g. NIST-traceable) calibration company, which can provide trained staff, the right calibration equipment to help reduce uncertainty and ensure compliance. These companies employ trained staff who will use the correct procedures and are less likely to make mistakes during the process. The calibration reports produced by these companies include uncertain values, making them valuable for facilities with high accreditation standards. While this option can provide more accurate and reliable results, it does come with additional costs from hiring a calibration company.
Regardless of who is performing the calibration, the steps involved are always the same. The first step is to decide how many points of calibration are required (usually 1 or 3, but may go up to 9), secondly to create a stable environment where the sensor and standard can be compared. If there is a deviation between the two, it may be necessary to offset the sensor value at a specific point (1, 3 or up to 9). After the sensor has been offset, it is essential to repeat the calibration process to ensure that the offset has correctly adjusted the sensor display readout. This helps to ensure the accuracy and reliability of the calibration process.
In order for the calibration to be considered valid, it is important to properly document and report the process. This includes accurately recording the steps taken, the standards used, and the values recorded during the calibration process. Proper documentation is necessary to accurately report any offsets that were performed and to ensure the accuracy and reliability of the calibration.
Validation: How to Prove Something is Fit For Purpose
Validation ensures the accuracy and reliability of lab equipment and processes. In addition to demonstrating proper calibration, validation also involves evaluating workflows, staff performance, data quality, and other factors. It is a comprehensive process that helps to ensure that the equipment and processes being used are operating correctly and producing accurate and reliable results. Proper validation is essential for maintaining the integrity and quality of the data produced in a laboratory setting.
Validation processes are often specific to each industry, laboratory and their respective business models, as they take into account the unique equipment and processes being used in that particular lab. In contrast, equipment calibration processes are generally the same regardless of the location or specific use of the equipment.
As there is no "one size fits all" approach to lab validation, a customized approach that is specific to the needs and goals of the business should be implemented. In the event of an issue or audit, it is important to have a “paper” trail documenting the validation process to ensure that the equipment and processes used are accurate and reliable.
Validation processes for laboratories typically involve two major components. The first step is to ensure that the equipment and rooms used for example storing samples or producing medicine meet the necessary specifications. While validation processes may be unique to each laboratory, there are still some standards that all labs must follow, such as the IQ (Installation Qualification), OQ (Operational Qualification), and PQ (Performance Qualification) protocols, which apply to equipment and software systems. It is important for laboratories to follow these and any other relevant standards in order to ensure the accuracy and reliability of their equipment and processes.
Briefly, they’re defined as follows:
IQ validates that equipment is correctly installed as per the manufacturer’s instructions (which, naturally, would usually include equipment calibrated as per those instructions as well).
OQ validates that equipment operates as intended within a range of operations specified by the manufacturer or dictated by a compliance standard.
PQ integrates usage into the protocols: is your equipment staying in line with standards as it’s being used?
The OQ and PQ aspects of the validation process can be the most labor-intensive. For example, in the case of a blood fridge, the first step in the validation process is to verify the accuracy of the equipment itself - which may be done by checking the display of the equipment. However, other factors must also be considered, such as the fridge's ability to recover quickly after the door is opened, how the temperature distribution inside the fridge changes depending on how full it is, and the fridge's ability to maintain a stable temperature in the event of a power failure. All of these factors must be carefully evaluated in order to ensure that the fridge is functioning correctly and can provide safe storage for samples.
To perform this type of validation, a multi-sensor mapping of the device (or room) is typically performed, using sensors placed at multiple points throughout the device, such as the corners and center. The temperature at these points, as well as the ambient temperature, is recorded over a predetermined period of time. The results are then compared to the storage criteria to determine if the device is suitable for its intended purpose. If the device passes the validation, it is considered fit for use. If it fails, it may need to be adjusted or repaired before it can be used.
For over 30 years, XiltriX has been dedicated to helping labs ensure the accuracy and reliability of their equipment, processes, and environment. We offer a 24/7 Support team to answer any questions you may have regarding your equipment, environment, and facility monitoring needs. If you would like to learn more about how XiltriX can help you optimize and streamline critical processes, contact us now.