Over time, medical devices can drift away from producing accurate measurements because of their internal components. This is common among all manufacturers, even the most trusted. As with all hardware, through frequent use their mechanical and electronic components wear and tear.
Instrument calibration is therefore an essential part of any measurement system, as it makes sure equipment is working properly and giving accurate readings.
In essence, it's the process of comparing the readings from an instrument to those given by a reference instrument or calibrator to ensure accuracy, reliability, safety, and compliance with industry standards.
Why calibrate equipment?
Calibrating equipment is vital for ensuring complete accuracy of test results. Once the type of instrument you're using has been calibrated, you can be more confident in the output.
Hearing test specialists must have a valid calibration certificate to make sure their audiograms are accurate. Without this, results might be questionable and not upheld in a legal context.
Inaccurate results can also lead to patients being incorrectly referred to occupational health physicians or general practitioners, which can cause inefficiencies that cost time and money.
Calibration vs verification
Calibration, validation and verification all share the common goal of ensuring a process is working as expected, but there's a difference between them. At a basic level, they can each be defined as below:
| Validation |
Verification |
Calibration
|
| Validation ensures a system delivers against its functional intent. |
Verification ensures a process or piece of equipment operates according to its stated specifications. |
Calibration ensures the measurement accuracy of an instrument meets a known standard. |
Verification typically involves using an electro-acoustic ear simulator to compare it with a previous reading. No absolute measurement exists, just a reference point. Verifications are usually completed daily or weekly.
Most PC-based audiometers offer calibration program options to update the date of calibration. If these updates aren't made, and users opt for verification only, subsequent audiogram results might display the original date, which can lead to liability problems.
What are the benefits of regular equipment calibration?
Completing regular medical equipment calibration checks provides several benefits:
- Accurate test measurements
- Complete confidence in the efficacy of your equipment
- Standardisation of measurements and the ability to replicate results
- No downtime or interruptions to your testing programme
- Regulatory compliance
How often should equipment be calibrated?
Medical devices should be calibrated according to specific manufacturer instructions and legal standards, which can differ by country. You should generally calibrate a piece of equipment when:
- The user instructions states it's time to calibrate - usually once or twice a year
- When using a pre-owned instrument from a company that doesn't specialise in calibration or servicing
- A specific amount of usage hours have elapsed (refer to instructions for specifics)
- An instrument vibrated or sustained damage that may have caused it to go out of calibration (especially important for portable devices)
- The observations raise questions or surprises, indicating possible damage to the equipment
ISO standards for medical devices
The International Organization for Standardization (ISO) is an international non-governmental organisation that develops and publishes proprietary, industrial, and commercial standards. ISO standards establish credibility and trust among consumers, clients and business partners.
In today's international marketplace, it ensures organisations adhere to global standards of safety, quality assurance and manufacturing operations. In the case of medical equipment, it's important that the following standards are observed:
| ISO 13485:2016 |
ISO 389-1:2017 |
IEC 60645-1:2017 |
ISO 13485:2016 is a standard for making medical devices, based on the ISO 9001 management system.
Having this standard demonstrates a company's ability to produce medical devices and services that consistently meet customer requirements and regulations. |
ISO 389-1:2017 is a standard for comparing populations globally when calibrating devices, like for mild hearing loss or normal hearing. |
IEC 60645-1:2017 specifies the general requirements for audiometers. This standard helps measure how well someone can hear compared to established reference levels using psychoacoustic tests. |
Equipment calibration services
Product accuracy and reliability is a crucial part of Amplivox’s commitment to excellence. Working with carefully selected partners, engineers and technicians, we deliver a state-of-the-art calibration and repairs service. We also hold full certification to the latest ISO 13485:2016 standard and are UKAS accredited where required.
To maximise the life of an instrument, we always check accuracy of measurements as well as compliance to manufacturer and international standards. We offer return-to-base calibration, and an on-site calibration service in the UK, to provide customers with full support.
Choose Amplivox for your medical equipment calibration to ensure your devices meet international standards and are fully traceable. If you want to know more about our calibration service, you can visit our calibration and repairs webpage. You can also contact our customer support team at +44 (0)1865 880 846. Alternatively, you can email us for more information.
References
International Organization for Standardization (ISO). Accessible at: https://www.iso.org/home.html
United Kingdom Accreditation Service (UKAS). Accessible at: https://www.ukas.com/