Result card

  • ORG11: What kind of quality assurance is needed and how should it be organised?
English

What kind of quality assurance is needed and how should it be organised?

Authors: Principal investigators: Valentina Prevolnik Rupel, Nika Berlic Investigators: Dominika Novak Mlakar, Taja Čokl, Plamen Dimitrov, Marta López de Argumedo

Internal reviewers: Americo Cicchetti, Daniela D'Angela, Marco Marchetti

Acknowledgments: /

Analysis of selected studies extracted from the basic literature search. One article, one report and one document with guidelines were found to be relevant to this question.

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Adequate quality assurance requires substantial efforts, due to the complexity of the screening process which extends from identification and invitation of the target population, to performance of the screening test and, if necessary, diagnostic work-up and treatment of screen detected lesions; and aftercare {5}.

According to the European guidelines {4}, European external quality assessment scheme should be developed to facilitate Europe-wide quality assurance of occult blood testing and enhance the reproducibility of testing within and between countries providing population screening.

Rigorous analytical quality assurance procedures must be adopted by laboratories providing gFOBT and FIT analysis for population screening. To minimise analytical and procedural variability, the number of laboratories used for population screening should be small {4}.

All laboratories providing screening services should be associated with a laboratory accredited to ISO 15189:2007, Medical laboratories - Particular requirements for quality and competence. The laboratory should be led by a qualified clinical chemist who is trained and experienced in the techniques used for analysis and in clinical quality assurance procedures. The laboratory staff should be appropriately trained and competent in the use of the analytical device/ instrumentation, quality control and assessment procedures and associated information technology {4}.

Quality assurance of FIT testing

Consistency in analytical performance must be assured by the adoption and application of rigorous quality assurance procedures. Manufacturer’s Instructions for Use must be followed. Laboratories should perform daily checks of analytical accuracy and precision across the measurement range with particular emphasis at the selected cut-off limit. Rigorous procedures need to be agreed and adopted on how internal quality control data is interpreted and how the laboratory responds to unsatisfactory results. Performance data, both internal quality control and external quality assessment data, should be shared and reviewed by a Quality Assurance team working across the programme. Sufficient instrumentation should be available to avoid delays in analysis due to instrument failure or maintenance procedures {4}.

Nevertheless prevention of delays of return samples to laboratory is one of the factors that contributes to quality assurance of FIT testing, Roon et al. (2011) in their study indicated that both positivity rate and detection rate of FITs do not decrease with prolonged sample return times up to 10 days. This means that a delay in sending the FIT back to the laboratory, of ups to at least 1 week, does not necessitate repeat sampling in case of negative result. this data also supports the use of FIT-based screening as a reliable tool for nationwide CRC screening programs {45}.

Quality assurance of gFOBT testing

Whilst an immunochemical test is recommended, programmes that adopt a traditional guaiac test need to apply additional laboratory quality procedures. To minimise variability and error associated with visual test reading, including manual results input, the following procedures should be considered {4}:

•             Use of appropriate temperature for artificial lighting and neutral-coloured walls in the reading laboratory;

•             Use of a national laboratory training programme to prosper consistency of interpretation;

•             A blinded internal QC check each day for each analyst prior to commencing testing;

•             Adoption of a monitoring programme to identify operator related analytical performance (e.g. positivity variability and bias); and

•             Double entry of test results.

 

Analytical quality assurance – Internal Quality Control (IQC) and External Quality Assessment Schemes (EQAS)

For those laboratories using visually read gFOBTs, the design of the test kit will influence the reliability of analysis. Reproducibility in detecting the blue gFOBT colour in the presence of dark faecal pigments depends on good staff training and experience but can be improved by other factors. The visual acuity and colour perception of the reader should be professionally checked and monitored. The colour of the test card surrounding the sample, the colour of surrounding walls and the colour temperature and brightness of artificial lighting all should be considered. The opportunity for errors due to operator fatigue should be minimised by enforcing periodic work breaks. The competence of staff to perform visual tests should be checked before they commence each batch of analysis, typically using preloaded test kits with known positivity that is hidden from the operator. A rigorous monitoring system should be adopted to identify staff, who has spot positivity rates which are markedly different to the mean or who exhibit marked variability {4}.

Most gFOBTs and point-of-care FIT devices have a means of checking the integrity of the device and reagents by way of a quality control check integral to the device. For gFOBT, this control can check whether guaiac has been applied across the whole of the test area and whether the hydrogen peroxide reagents are working correctly. Point-of-care FIT devices provide a similar check of reagent integrity but are unsuitable for population screening {4}.

The case for automation in population screening programmes is a strong one, and should significantly influence the choice of an acceptable occult blood testing system. Automated FIT analysis will require internal quality control procedures appropriate to the chosen technique and instrument. As a minimum, laboratories should adopt the manufacturers’ instructions for use, and give consideration to what additional internal quality control measures can be used to check instrument accuracy and imprecision throughout the period of analysis. Good analytical performance is particularly important at the selected cut-off concentration, and quality control measures should reflect that requirement {4}.

Participation in an external quality assessment scheme (EQAS) is seen as mandatory for tests performed in a clinical laboratory. Participation in an EQAS enables assessment of bias between participating laboratories, and is particularly important for a national screening programme utilising several laboratories. The availability of an EU-wide EQAS is desirable. National population screening programmes should have quality assurance procedures that enable oversight of the analytical performance of all screening laboratories. Satisfactory performance in an EQAS provides an objective criterion of competence {4}.

Quality assurance and staff

The prime importance of quality assurance should also be included in basic training of other staff involved in screening process, not just those in laboratories: public health specialists, administrative and clerical staff, general practitioners, nurses, endoscopists, who must be strongly engaged in quality assurance, and also radiologist. In addition, quality control of surgery is particularly important within a screening programme, as it is essential that individuals with lesions detected at screening are afforded the highest possible standards of care. The pathologist has an essential role in the quality assurance of surgery by assessing the completeness of tumour excision in surgical resection specimens {4}.

Achieving and maintaining high quality at every step in the screening process requires an integrated, population-based approach to health service delivery. This approach is essential in order to make screening accessible to those in the population who may benefit and in order to adequately monitor, evaluate and continuously improve performance {5}.

In the case of positive FOBT result the follow-up phase is necessary. Participants with positive feedback require further assessment (colonoscopy). Usually information about colonoscopy is notified at the same time as positive results. The information provider is usually so called patients navigator (PN). This is an individual whose role has been described as providing individualized assistance (by telephone and/or by direct contact) to a patient to both educate and help them overcome healthcare system barriers related to, for example, doctors’ offices, clinics, hospitals, outpatient centres, payment systems. Social and logistical services provided by patient navigators could be for example facilitating communication among patients/family members/survivors/healthcare providers, coordinating care among providers, facilitating appointments and follow-up appointments, and facilitating access and transportation to services facilities. Patient navigators could be trained community health workers/advisors who have close ties to the local community or trained social workers/health professional/volunteers or belong to a specific organization {4}.

According to the manufacturer’s information on the FIT technology (FOB Gold/ SENTiFOB analyser), the FOB Gold® NG assay is a IVD laboratory test for professionals use, so a simple training is required in order to inform the users about the use of the product and results interpretation. The typical professional laboratory operator is able to use the test in a very short time.

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Critical
Partially
Rupel P et al. Result Card ORG11 In: Rupel P et al. Organisational aspects In: Jefferson T, Cerbo M, Vicari N [eds.]. Fecal Immunochemical Test (FIT ) versus guaiac-based fecal occult blood test (FOBT) for colorectal cancer screening [Core HTA], Agenas - Agenzia nazionale per i servizi sanitari regionali; 2014. [cited 21 June 2021]. Available from: http://corehta.info/ViewCover.aspx?id=206

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