Why the Importance of Pipette Calibration Should Be on Your Radar

Defining Pipette Calibration

So what is pipette calibration?

Calibration of a pipette is the process of verifying and adjusting the accuracy and precision of a pipette to ensure it dispenses the correct volume. This is typically done by comparing the volume a pipette delivers against a known standard, often through gravimetric testing, which involves weighing the dispensed liquid. 

This process helps detect and correct any deviations in pipetting performance, ensuring the reliability of your experiments. Calibration should be conducted on a regular basis to account for wear and tear, environmental conditions, or any unintentional misuse- those simple slips and drops - even onto your benchtop - can be enough to take a low volume instrument out of range.

What is metrology?

Metrology is the science of measurement, and it plays a critical role in ensuring accuracy and precision across various industries, including laboratory sciences. It focuses on the establishment of measurement standards, methods, and systems to guarantee that measurements are consistent and reliable.

In the context of pipette calibration, metrology is essential because it ensures that pipettes and micropipettes deliver accurate and precise volumes as intended. 

Pipettes must be calibrated regularly to meet standardized metrological requirements, which involve checking the instrument's performance against known reference standards to ensure it is delivering the correct volume.

In short, principles of metrology are given higher levels of quality and lower levels of uncertainty - which is why we maintain the highest level of accreditation - ISO17025, via A2LA.

So, why should I calibrate my pipette?

Why Calibrate? The Importance of Pipette Calibration

There are many reasons why you should regularly calibrate your pipettes and micropipettes. To put it simply, accurate pipetting is the foundation of good science, and calibration is how a high level of accuracy and low level of uncertainty is maintained. To put it in more technical terms, we have outlined some key reasons to calibrate your pipettes regularly.

Top 4 Reasons to Calibrate Your Pipettes

1. Accuracy and Precision

The most important reason for calibrating your pipette is to maintain accuracy and precision. Pipettes are designed to transfer precise volumes of liquids, and even small deviations in volume can lead to significant errors in your experiment, assay, or process. 

For instance, in experiments that require reagents to be mixed in exact proportions, an uncalibrated pipette could lead to flawed data, compromising the validity of the results. Calibration ensures that your pipette works as expected, delivering exact volumes consistently.

2. Data Integrity

Inaccurate pipetting directly impacts data integrity. Inconsistent or inaccurate volumes can lead to erroneous results, which in turn may affect the interpretation of an entire experiment. 

For example, in drug development, an incorrectly calibrated pipette can lead to dosage miscalculations, skewing the outcome of clinical trials. Proper calibration helps maintain the reliability of your results and supports the reproducibility of experiments, which is crucial in scientific research - and lowering critical measures such as consumer risk.

3. Regulatory Compliance

In many regulated industries, like pharmaceuticals, diagnostics, and food safety, laboratories are required to follow strict guidelines that often include regular calibration of equipment. 

Organizations such as the ISO and FDA require documentation proving that pipettes are calibrated regularly. Failure to comply can lead to penalties, fines, or disqualification of your research. The calibration of micropipettes ensures that your lab stays compliant with industry standards.

4. Cost Efficiency

Regular calibration of pipettes can lead to significant cost savings in the long run. By ensuring that your pipette is accurate, you reduce waste caused by inaccurate liquid transfers. 

More importantly, it prevents costly mistakes that may arise from flawed experimental results. In the worst-case scenario, repeated errors due to inaccurate pipetting can lead to the complete failure of a study, resulting in a productivity and financial impact.

How Often Should Pipettes Be Calibrated?

The frequency of calibration depends on the pipette's usage and the critical nature of the experiments being performed. As a general rule, pipettes should be calibrated at least once a year. 

However, if you use your pipettes frequently, or in applications where precision is critical, more frequent calibrations are recommended, such as every 3-6 months. Additionally, if your lab operates under strict regulatory standards, you may be required to follow a specific calibration schedule.

Ultimately, the best way to determine how often pipettes should be calibrated is to assess the usage intensity and critical nature of your experiments. High-precision environments often require stricter calibration schedules to maintain compliance and accuracy.

Additionally, there are methods of interval analysis that can be performed managing the balance between cost and quality. 

While companies typically default to the bias of three-month intervals set on calibration, your organization may find that utilizing software and statistical analysis, such as the asset and lab management tool that operates our service business, can help make these determinations between reliability and failure rate of your instruments.

How is Calibration Performed? The Pipette Calibration Process 

The calibration of pipettes is a straightforward but meticulous process. It generally involves dispensing a specific volume of liquid and weighing it to verify accuracy, using gravimetric testing. Here's an outline of the process:

1. Pre-check: Before calibration, the pipette is inspected for physical damage, dirt, or other issues that could affect performance. Taking extra effort to perform cleaning, preventative maintenance, check and replace common pipette parts is a frequently overlooked step to save time and labor - but can be detrimental to driving long-term cost of operating your instrument program.
2. Testing: The pipette is used to dispense a set volume of liquid, usually specialized water. The dispensed liquid is then weighed on a precision balance. This weight is compared to the expected value based on specification provided by manufacturer, ISO 8655 or custom specification based on internal SOP
3. Adjustment: If the dispensed volume is outside the acceptable range, the pipette is adjusted to correct any deviation.
4. Post-test: After adjustment, the pipette is tested again to ensure it meets the required standards for accuracy and precision.

A balance is the cornerstone piece of equipment for pipette calibration. Having a proper balance that is adequately calibrated is imperative. An inadequate balance, even under the right environmental conditions will prevent the best technicians from calibrating pipettes correctly. 

The following chart from ISO 8655:2022 shows what type of balance is needed for the different sizes/types of pipettes:

An ultra microbalance is needed for the 2μl to 50μl micropipettes because it reduces the margin of error. Ultra microbalances display a more accurate volume the pipette dispensed by showing the microgram volume. 

An analytical balance will display a volume of 2μl by only displaying the milligram volume. For example, an Eppendorf Research® plus pipette at the volume of 2μl at minimum needs a balance that shows 7 decimals. 

What to Look for In Pipette Calibration Services

There are many factors to consider when choosing a pipette calibration service provider including cost, convenience, and friendly customer service. However, when it comes to the quality of the calibration service being performed here are the top 5 things to think about. 

1. Appropriate Accreditation
   It is strongly recommended and in many cases required that each pipette be serviced by an ISO 17025-accredited laboratory. ISO 17025 accreditation complies with the International Organization for Standardization (ISO) criteria.
   
   ISO 17025 “specifies the general requirements for the competence to carry our tests and/or calibrations, including sampling. It covers testing and calibration performed using standard methods, non-standard methods, and accredited laboratory-developed methods.” Pipette.com is proudly an ISO 17025-accredited calibration lab.
2. Controlled Environment
   Pipettes should be calibrated in a controlled environment with specific attention to factors such as temperature, humidity, and atmospheric pressure. These conditions are important because they directly affect the accuracy and precision of liquid measurements. 
   
   Stone work tables also ensure there are no vibrations affecting calibration Pipette.com ensures that all pipettes being calibrated in our lab are held to these controlled conditions.
3. Proper Equipment
   Off-site calibration facilities, such as Pipette.com, have the correct balances and their balances are checked for calibration verification on a weekly basis and calibrated to NIST standards once a year. This ensures that Pipette.com is able to provide the most accurate and precise calibration results for all models and sizes of pipettes.
4. Access to Spare Parts
   If repairs are required during the calibration process, it is essential to work with a service provider who has access to spare parts on site to avoid delays. Pipette.com has the largest inventory of spare parts in the industry.
5. Comprehensive Pipette Management Software
   Working with a calibration lab that provides access to a top tier data management system ensures that all pipette data is synced, making your job much easier. Qualer asset management software provides you with excellent data management that makes calibrating with us all the more simple and convenient. 

Calibrate Your Pipettes With the Experts

Are you ready to start discussing how Pipette.com can provide you with excellent calibration service? Let’s connect today!

Give us a call at 800-243-3232, send an email to service@pipette.com, or schedule a meeting with an account manager through the link below!