ISO 17025:2017 sets the standard for testing and calibration laboratories to ensure they offer services that meet the technical and quality requirements of their customers. A critical aspect of this standard involves the selection of test and calibration methods. This article will discuss how laboratories should choose methods to comply with ISO 17025 and ensure customer satisfaction.
Understanding the Customer’s Requirements
The cornerstone of ISO 17025 is the alignment of laboratory procedures with customer needs. When a customer approaches a laboratory, they may specify a method for testing or calibration. The laboratory must evaluate this request against current industry standards to ensure the method is appropriate and up-to-date. If the customer’s suggested method is outdated or unsuitable, the lab is responsible for informing the customer and recommending a more current or appropriate alternative.
Selection of Methods
When the customer does not specify a method, the laboratory has the responsibility to select an appropriate method. The selection is typically based on the following criteria:
- Standards Compliance: The method should comply with international, regional, or national standards.
- Technical Organizations: Methods recommended by reputable technical organizations should be considered.
- Scientific Literature: Methods published in scientific texts or journals offer a peer-reviewed basis for selection.
- Manufacturer Specifications: For equipment-specific procedures, the manufacturer’s specified method is often the most suitable.
- Laboratory-Developed Methods: These can be used provided they have been verified for the intended use.
Ensuring the Use of Current Methods
In adherence to ISO 17025:2017, laboratories must use the latest valid version of the method. However, there may be situations where the latest method is not applicable or possible to use. In such cases, the laboratory must provide a clear rationale for this choice. For methods that are sufficiently detailed and unambiguous, further documentation is not required unless there are optional steps or additional details necessary for the lab’s specific application.
Verification of Method Performance
Prior to introducing a new method, the laboratory must perform a verification process. This process ensures the laboratory can achieve the required performance and produce reliable and accurate results. Verification includes a robust evaluation of the method’s suitability under the laboratory’s specific conditions. Records of this verification must be maintained.
Method Revision and Re-verification
When a standard method is revised by the issuing body, the laboratory must re-verify the method to the extent necessary. This ensures that any changes in the method do not adversely affect the lab’s ability to achieve the desired performance.
Conclusion
The selection and verification of test and calibration methods are fundamental to a laboratory’s compliance with ISO 17025:2017. By following these guidelines, laboratories not only meet the standard but also uphold the trust and confidence of their customers. This commitment to quality and continuous improvement positions the laboratory as a reliable partner in the scientific and industrial community.
Here’s a hypothetical scenario from a chemical testing laboratory:
Scenario: Determination of Lead Content in Drinking Water
Test Parameter Range:
- Acceptable lead concentration in drinking water: less than 10 µg/L (micrograms per liter)
Available Methods:
- Atomic Absorption Spectroscopy (AAS)
- Range: 1 – 100 µg/L
- Precision: ±0.5 µg/L
- Sample Throughput: 5 samples/hour
- Cost: High
- Anodic Stripping Voltammetry (ASV)
- Range: 0.1 – 50 µg/L
- Precision: ±0.1 µg/L
- Sample Throughput: 20 samples/hour
- Cost: Moderate
Customer’s Requirements:
- The customer, a bottled water company, requires the lead content to be measured with high precision to ensure compliance with stringent safety standards.
- They need to test multiple samples daily due to high production volume.
- Cost-effectiveness is also a concern since the testing will be a routine procedure.
Selection Justification: While AAS is a well-established method with a suitable range for detecting lead in water, it is less cost-effective and has a lower throughput compared to ASV. For the customer’s needs, ASV is the more appropriate method because:
- Precision: ASV offers a high level of precision (±0.1 µg/L), which is suitable for ensuring compliance with safety standards.
- Throughput: ASV can process more samples per hour, aligning with the need for high-volume testing.
- Cost: The moderate cost of ASV is more in line with the customer’s requirement for a cost-effective routine testing procedure.
Therefore, we recommend using Anodic Stripping Voltammetry (ASV) for the customer’s lead content analysis in drinking water to meet their requirements for precision, volume, and cost.
Here’s a hypothetical scenario from a geochemical testing laboratory focused on mineral ore analysis:
Scenario: Quantification of Gold Content in Ore Samples
Test Parameter Range:
- Detection range for gold in ore samples: 0.5 – 100 ppm (parts per million)
Available Methods:
- Fire Assay with Atomic Absorption Spectroscopy (FA-AAS)
- Range: 1 – 50 ppm
- Precision: ±0.2 ppm
- Sample Throughput: 10 samples/day
- Cost: High
- Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
- Range: 0.01 – 1000 ppm
- Precision: ±0.05 ppm
- Sample Throughput: 30 samples/day
- Cost: Moderate
Customer’s Requirements:
- The customer is a mining company that requires analysis of gold content across a wide concentration range due to the varying quality of ore from different mining sites.
- They need a method that can accommodate low-grade to high-grade ore analysis.
Selection Justification: Fire Assay with AAS is a traditional method for gold quantification, known for its high precision. However, its narrower detection range limits its application for samples with very high gold content.
On the other hand, ICP-MS offers a much broader detection range, which is crucial for this customer’s requirements, as it can measure both low-grade and high-grade ores with great accuracy. The advantages of ICP-MS for this scenario are:
- Range: ICP-MS’s broad detection range (0.01 – 1000 ppm) means it can accurately measure gold content across all expected levels found in the customer’s ore samples.
- Precision: While both methods offer high precision, ICP-MS provides sufficient accuracy for the purpose of ore grading.
- Throughput: ICP-MS has a higher sample throughput, beneficial for a mining company that likely needs to process a large volume of samples.
Given the need for a wide detection range and high throughput, ICP-MS is the recommended method for the customer’s gold quantification needs, enabling them to efficiently assess the value of their mineral resources.
In this example, the selection of ICP-MS is clearly justified by the customer’s requirement for a wide-range detection method capable of handling high throughput, which is crucial for a commercial mining operation.
About the author
Dr. Sambhu Chakraborty is a distinguished consultant in quality accreditation for laboratories and hospitals. With a leadership portfolio that includes directorial roles in two laboratory organizations and a consulting firm, as well as chairmanship in a prominent laboratory organization, Dr. Chakraborty is a respected voice in the field. For further engagement or inquiries, Dr. Chakraborty can be contacted through email at director@iaqmconsultants.com and info@sambhuchakraborty.com. Additional resourcesand contact information are available on his websites, https://www.quality-pathshala.com and https://www.sambhuchakraborty.com, or via WhatsApp at +919830051583