JUZGADO CUARTO MERCANTIL DEL PRIMER DEPARTAMENTO JUDICIAL DEL ESTADO

testing laboratories

Robert W. Góra Institute of Physical and Theoretical Chemistry Wrocław University of Technology

Quality management systems Robert W. Góra Introduction and Historical Outline From Statistical Process Control to Total Quality Management ISO 9000 standards Conformity Assessment QMS in Calibration and Testing Laboratories Technical requirements for calibration and testing laboratories

Personnel and Environmental Conditions Test and Calibration Methods Equipment and Measurement Traceability Sampling and Handling of Test and Calibration Items Quality Assurance of tests and calibrations. Reporting the results Key factors determining correctness and reliability of the

results

ISO/IEC 17025 standard identifies the key factors that determine the correctness and reliability of the tests and/or calibrations performed by a laboratory. These include:

• technical competence of personnel,

• accommodation and environmental conditions,

• validation of the methods,

• traceability of measurements,

• calibration and maintenance of the test equipment,

6.89 Personnel

• The laboratory management shouldensure the competenceof all its personnel performing specific tasks. Competence of staff should bereviewed and re-assessedon a regular basis.

• The laboratory should have apolicy and procedures for identifying training needsand providing training of personnel. The goals in this respect should be clearly formulated.

• The laboratory should use personnel who areemployed by, or under contract to, the laboratoryand maintain current job descriptions for managerial, technical and key support personnel involved in tests and/or calibrations.

• Staff should be qualifiedon the basis of appropriate education, training, experience and/or demonstrated skills, as required.

• Personnel should be authorizedto perform particular types of sampling, test and/or calibration, to issue test reports and calibration certificates, to give opinions and interpretations and to operate particular types of equipment.

• When using staff who are undergoing training or are contracted, appropriatesupervisionmust be provided.

• The laboratory should ensure that theenvironmental

conditions do not invalidate the resultsor adversely affect

the required quality of any measurement.

• The laboratory shouldmonitor, control and record

environmental conditionsas required by the relevant

specifications, methods and procedures or where they influence the quality of the results.

• Depending on the technical activities concerned, due

attention should be paid, for instance, to:

• biological sterility,

• dust,

• electromagnetic disturbances and electrical supply,

• radiation,

• humidity and temperature,

• sound and vibration levels.

• There must beeffective separationbetween neighboring

areas in which there are incompatible activities toprevent

cross-contamination.

6.91 Some Specific Considerations for Chemical and

Microbiological Testing26

In the case of chemical analysis, thecross contamination

between samples and possible environmental contamination of

samplesare likely to be the key concern – particularly for the

substances which are being tested for at trace levels. Although, it is quite common to monitor the temperature of

chemistry laboratories, this is rarely necessary.In practice, the

variations in modern borosilicate volumetric glassware over a temperature range in which personnel will be comfortable is negligible relative to other sources of uncertainty of

measurements.

The only reason for monitoring the temperature is that data will be affected if a specific range of temperature is not observed. This might be the case for some precision scientific instruments. For instance the ICP-MS environment must be free of dust, corrosive vapors and vibration, and maintained at a cool and stable

temperature (typically 18-23◦C with less than 2◦C drift per hour).

26_{Complying with ISO 17025. A practical guidebook. United Nations}

Microbiological Testing27

The following general rules should be observed for good practice in general chemical testing work:

• Only very diluted solutions of standards necessary for the equipment calibration should be ever introduced into areas where the samples are being handled and processed.

• Precautions should be taken to avoid spillage of standards.

• The preparations (and possibly testing) of samples containing high levels and low levels of the same targets should be carried out in well separated rooms with their own glassware.

• Enforce good housekeeping and tidiness by general management pressure.

6.93 Some Specific Considerations for Chemical and

Microbiological Testing28

In the case of microbiological laboratories, the potentialspillage should also be easily contained and thoroughly cleaned up. Impervious bench tops with good seals against walls and floor and around fittings such as sinks are expected and floors should be continuous sealed surfaces.

Microbiology laboratories will often need to beair-conditioned

with split type units and all windows sealed to prevent opening.

Entry to the laboratory should always bedouble doored with a

vestibuleand changing/washing area.

28_{Complying with ISO 17025. A practical guidebook. United Nations}

Microbiological Testing29

The laboratory must keep the reference cultures of organisms for control purposes. The following precautions help to avoid contamination:

• Clear segregation of samples, references and media storage.

• Segregated area for handling the references, ideally with a laminar flow cabinet.

• Dedicated laboratory coats and footwear with a changing area where staff can wash.

• A planned cleaning regime for the laboratory, covering benches, floors, windows, light fittings, ventilation grills, air conditioners, water baths and autoclaves.

• Documented procedures for dealing with spillages and records of spillages and action taken.

• Monitoring temperature and humidity: limits need not be stringent but humidity above 50% and temperatures above 25◦C can lead to problems of mould growth.

6.95 Test and calibration methods and method validation

Selection of Methods

• The laboratory should use appropriate test or calibration

methods (including methods for sampling)which meet the

requirements of the clientand, where possible,methods

published as national, regional or international standards, by reputable technical organizations or in relevant

scientific texts or journals.

• If it is necessary to employ non-standard methods, these

should be fullyvalidated and documentedto show that

they are appropriate and fit for purpose. These must be also agreed with the client.

For new methods, procedures should be developed containing at least the following information:

• appropriate identification and scope,

• description of the type of item to be tested or calibrated,

• parameters or quantities and ranges to be determined,

• apparatus and equipment, including technical performance requirements,

• reference standards and reference materialsrequired,

• environmental conditions required and any stabilization period needed,

• description of the procedure, including preparation of items, calibration and adjustment of the equipment before the use and the methods of recording the results,

• criteria and/or requirements for approval/rejection, data to be recorded and the method of analysis and presentation,

6.97 Validation of methods

• Validation is the confirmation by examination and the

provision of objective evidence that the particular requirements for a specific intended use are fulfilled.

• In order to confirm that the methods arefit for the intended

use, the laboratory must validate:

• non-standard methods,

• laboratory-designed/developed methods,

• standard methods used outside their intended scope, and amplifications and modifications of standard methods

• Although it is not necessary for the laboratory to validate

standard methods used within their intended scope,the

laboratory must confirm that it can properly operate

standard methodsbefore introducing the tests or

calibrations. If the standard method changes, the confirmation should be repeated.

• The validation should be as extensive as it is necessary to

meet the intended requirements. Generally it should demonstrate:

• the scope of applicability in terms of samples and numerical range,

• selectivity,

• robustness in use,

• accuracy, precision and bias,

• linearity, detection limit (LOD), and limit of quantitation (LOQ)

• limit of repeatability and/or reproducibility,

• the expanded uncertainty for a specified level of confidence.

• The laboratory shouldrecord the results and the

procedureused for the validation, and astatement as to

6.99 Estimation of measurement uncertainty

• Calibration and testinglaboratories should have and apply procedures for estimating uncertainty of measurements.

• However, in certain cases the nature of the test method may preclude rigorous, metrologically and statistically valid, calculation of measurement uncertainty. In these cases the

testing laboratory should at least attempt to identify all the components of uncertainty and make a reasonable estimation.

• When estimating the uncertainty of measurement, all uncertainty components which are of importance in a given situation should be taken into account usingappropriate methods of analysis.

The Guide to the Expression of Uncertainty in Measurement

(GUM)30_{is recognized by EA as the master document on}

measurement uncertainty.31_.

30_{Guide to the Expression of Uncertainty in Measurement. BIPM, IEC, IFCC,}

ISO, IUPAC, IUPAP, OIML. International Organization for Standardization, 1995.

31_{EA-4/16 (rev.00), EA Guidelines on the Expression of Uncertainty in}

• All calculations and data transfers in the laboratory must be subject to appropriate checks in a systematic manner.

• Anyin-house softwarefor acquisition and processing of data (including spreadsheets)must be documented and validatedfor the intended use.

• Procedures forprotecting the datashould be established and implemented.

6.101 Equipment

ISO 17025 requires a complete history of each piece ofequipment, understood to encompass any items which may affect the validity of measurements or calibrations. This includes the detailed records of the following activities required by this standard:

• Checks and calibrationscarried out before the equipment is placed in

service and its unique identification.

• Checks carried out tomaintain confidence in the calibration statusof the

equipment, according to a defined procedure.

• Authorization of personneland provision of any relevant instructions and

manuals which should be readily available for use.

• Documentation and implementation of theprocedures for handling, use

and maintenance of the measuring equipment.

• Service of the equipmentthat has been shown to be defective or outside

the specified limits and analysis of the potential influence on previous

tests and/or calibrations (control of nonconforming work).

• Indication of the status of calibration.

• The equipment should be under permanent control of the laboratory.

When, for whatever reason, it goes outside its direct control it must be

ISO 17025 specifically requires maintenance of the following records for each item of the equipment and its software:

• the identity of the item of equipment and its software,

• the manufacturer’s name, type identification, and serial number or other unique identification,

• checks that the equipment complies with the specification,

• the current location, where appropriate,

• the manufacturer’s instructions, if available, or reference to their location,

• dates, results and copies of the reports and certificates of all calibrations, adjustments, acceptance criteria, and the due date of the next calibration,

• the maintenance plan, where appropriate, and maintenance carried out to date,

• any damage, malfunction, modification or repair to the equipment.

6.103 Metrological Traceability

“Metrological traceability is property of a

measurement result whereby the result can be related

to a reference through adocumented unbroken chain

of calibrations, each contributing to the measurement uncertainty.”a

a_{VIM, International vocabulary of metrology — Basic and general concepts}

and associated terms. Joint Committee for Guides in Metrology (JCGM).

Measurement traceability in Testing and Calibration Laboratories

Laboratories are required to implement a calibration system which ensures that the results of any tests or calibrations performed are comparable with those of any other laboratory.

The key element of such a system is themetrological

traceabilityof any measurement through anunbroken chain of

comparisonsto a recognizedinternational standard for the

measurandin question which, wherever possible, is required to

There is an establishedcalibration hierarchy.32

At theinternational level, decisions concerning theInternational System of Units (SI)and the realization of the primary standards are taken by theConférence Générale des Poids et Mesures (CGPM).

The Bureau International des Poids et Mesures (BIPM)is in charge of coordinating the development and maintenance of primary standards and organizesintercomparisonson the highest level.

TheNational Metrology Institutes (NMI)are the highest authorities in metrology in almost all countries (in Poland GUM). In most cases they maintain thenational standardsof the country which are thesources of traceabilityfor the associated physical quantity in that country.

TheAccredited Calibration Laboratoriesprovide calibration services according to their scope of accreditation, identifying the specified measurands and theirbest measurement capabilityi.e. the smallest uncertainties that can be achieved with the suitable measuring devices. Theirreference standardsare compared, at appropriate intervals, with reference standards of NMI.

Quality management systems Robert W. Góra

In document -SUMARIO- GOBIERNO DEL ESTADO PODER EJECUTIVO CONSEJERÍA JURÍDICA DIRECCIÓN DEL DIARIO OFICIAL ORGANISMO PÚBLICO DESCENTRALIZADO (página 41-49)