The Preferred Reporting Items for Systematic Reviews (PRISMA) was used to guide the reporting of this review.²⁰ This systematic review is registered in PROSPERO with the registration number: CRD42022338151.

For this systematic review, we searched Medline (i.e., PubMed), Web of Science, and Google Scholar in June 2022. The terms ‘ISO 15189 accreditation’, ‘laboratory quality management system’, and ‘medical laboratories’ were used in various combinations with the following words: ‘success’, ‘strengthening’, ‘improvement’, and ‘implementation’. Additional search terms, namely ‘Africa’, ‘Asia’, ‘low-income countries’, and ‘countries with limited resources’ were used to narrow down the search results. The results were cross-referenced with the World Bank’s 2022 list of low-, lower-middle-, and upper-middle-income countries.²¹ The reference lists of all the selected studies were thoroughly inspected to identify additional studies of interest.

Two reviewers screened the titles and abstracts against the eligibility criteria. All the potentially relevant articles were accessed in full-text format. Both reviewers independently made the final decision on whether to include each of the articles in this review, and conflicting decisions were discussed and resolved. The articles were subjected to content analysis by two reviewers, each of whom extracted and documented the key findings of the included studies.

Articles that were published in English between 2012 and 2022 and contained primary data that demonstrated the results of QMS implementation in medical laboratories in LMICs according to the standard’s requirements were included in the review. No restrictions were placed on the research design.

We excluded studies without a direct focus on the implementation of the standard’s requirements, as well as studies whose reports of such implementation did not include information about the immediate evidence of improvement in the quality of laboratory services. We also excluded studies conducted in non-medical laboratories (forensic, research, etc.).

We used the grounded theory to identify the KSFs, with the data analysed using a multistage procedure of open, axial and selective coding.²² Conceptualisation and data categorisation were done by one of the reviewers, after which another reviewer assessed the theoretical relevance of the selected categories. Any discrepancies in the reviewers’ definition, formulation or integration of the categories were resolved through discussions until an agreement was reached.

One reviewer critically evaluated the methodological quality of the papers using the critical appraisal tool described by Hawker et al.²³ According to the tool, studies can be assessed based on nine criteria: abstract and title; introduction and aims; method and data; sampling; data analysis; ethics and bias; results; transferability or generalisability; implications and usefulness. Each criterion was evaluated on a scale of 1 (very poor) to 4 (good) in accordance with the developed protocol.²³ Thus, each article could receive from 9 to 36 points, indicating the methodological rigour of the study. Another reviewer cross-checked 30% of the assessed studies and expressed full agreement with the initial assessment of their quality.

A total of 952 records were identified through databases (n = 880) and citation (n = 72) searching. After removing the duplicates, 753 abstracts were retrieved and screened. After applying the inclusion and exclusion criteria, two independent reviewers narrowed down the references to 59 full-text versions of articles. The analysis of those articles led to 32 of them being included in the final analysis (Figure 1).

Most of the studies included in this review were conducted in Africa: Ethiopia (n = 6), Kenya (n = 4), Tanzania (n = 3), Lesotho (n = 3), Botswana (n = 2), Nigeria (n = 2), Cameroon (n = 2), Mozambique (n = 2), Rwanda (n = 1), Zambia (n = 1), Ghana (n = 1), Zimbabwe (n = 1), and Benin (n = 1).^{24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49} Studies reporting data from the Southeastern Asian countries (Cambodia [n = 2], Vietnam [n = 2]),^50,51,52,53 the Caribbean Region (n = 1),⁵⁴ and Armenia (n = 1)⁵⁵ were also included in the analysis (Supplementary Table 1). We found no relevant studies conducted in Eastern Europe (Ukraine, Belarus, Moldova, Romania, etc.) or Central Asia (Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, Turkmenistan).

The 32 studies included in this review demonstrated the results of successful QMS implementation in 280 medical laboratories; 266 showed quality improvement and 14 met the standard’s requirements and achieved accreditation (Table 1). Two hundred and seventy-eight out of the 280 laboratories were in the public sector. Most (n = 237) of the studies were conducted in laboratories enrolled in the Strengthening Laboratory Management Toward Accreditation programme.

The included studies varied in their methodological quality: two studies received the highest attainable score – 36 points, 13 scored between 33 and 35 points, 16 scored between 29 and 32 points, and just one scored 25 points. Studies lost points mostly due to insufficient presentation of the methods of research (n = 5; 16%) and result bias (n = 22; 69%).

The use of open and axial coding techniques²² allowed the identification of 10 different categories, which represent the necessary activities, conditions, and strategies needed to improve the quality of laboratory services by implementing QMS in accordance with the standard. Those categories were named ‘key success factors’ as they are crucial to the implementation of the standard’s requirements (Table 2). Across the 32 studies, the most frequently identified KSFs were ‘mentorship’ (n = 27; 84%) and ‘trained laboratory staff’ (n = 26; 81%), while the least common factors were ‘personnel management’ (n = 8; 25%) and ‘QMS implementation strategy’ (n = 8; 25%).

Using the selective coding technique,²² the 10 KSFs were integrated based on their properties and paradigmatic connections into a ‘model of success for laboratory QMS implementation’ (Figure 2). This model consists of three underlying factors, namely preparing for change, resource availability, and effective project management, each comprising three separate KSFs. These three underlying factors are united around their own central factor, which serves as a stabilising factor and the core of the model of success, without which other factors are ineffective.

Hospital management dedication to laboratory QMS implementation, laboratory personnel commitment to quality improvement, and trained laboratory staff are the three KSFs that ensure readiness for change among the contributing parties.

A high level of readiness for change is crucial to the implementation of any organisational change,⁵⁶ including in the medical sphere,^57,58 and medical laboratories are no exception. The starting point of QMS implementation and laboratory quality improvement should be sufficient preparation for the implementation initiative. Sufficient preparation means that all stakeholders involved in the process of QMS implementation must agree that there is a need for change and possess the required theoretical and practical knowledge.

Firstly, the need for change must be recognised at the top management level to ensure the provision of essential financial support^{25,28,40,45,52} and organisational conditions.^{29,37,40,44,51,52} Nevertheless, top hospital management can only provide the required assistance when there is a clear understanding of the benefits of effective QMS to the patients and the facility in general.²⁸ The lack of such understanding creates a strong administrative barrier to the laboratory’s quest for accreditation.³¹

At the same time, the rejection of new standards and resistance to change^29,31,39,43 by laboratory personnel could nullify the efforts of senior management aimed at implementing laboratory QMS. Laboratory personnel commitment to quality improvement is thus one of the KSFs for the improvement of laboratory service quality.^{24,26,29,30,34,37,38,39,40,41,43,45,52} However, one must realise that the implementation of the standard’s requirements in medical laboratories often calls for considerable changes in personnel’s daily routines. Reorganising the existing processes and introducing new ones during routine laboratory practice often leads to increases in workload.^{25,29,31,41,42,45,53,55} This could significantly impact personnel’s attitude to change, more so when the personnel do not see the need for organisational changes. Involving personnel in the decision-making process and teaching them the basics of QMS could help overcome the reluctance to change and develop personnel commitment.^{29,30,37,38,40,49}

Staff awareness of QMS is another component of the organisational readiness to implement changes and is also one of the two most common KSFs in the selected studies. Implementing laboratory QMS requires ensuring proper theoretical and practical preparation in advance. Managerial and technical laboratory personnel must be conversant with the standard’s requirements and practical applications.^{24,27,28,29,30,31,34,37,39,40,42,43,44,46,47,48,49,50,51,52,54,55} Technical personnel should also be aware of the standard’s requirements for technical procedures,^22,24 and laboratory management personnel must be familiar with organisational management, leadership, and improvement activities.^26,32,50,51

Physical facilities, staffing and QMS implementation strategy are the three main resources that could either facilitate or inhibit the overall laboratory improvement process.

Physical facilities represented by adequate infrastructure^{26,29,30,31,39,48} and independent financial^{28,29,30,34,35,43,45,48,51,54} and material^{29,31,40,47,48} resources are basic requirements for good laboratory practice. The implementers must understand that substantial investments are necessary to comply with the technical requirements of the standard regarding laboratory and office facilities, environmental conditions, and laboratory equipment, reagents, and consumables.

Adequate staffing is the second valuable resource that greatly affects the QMS implementation process. The lack of human resources^{25,28,29,37,42,55} and employee turnover^{30,31,32,40,41,49,54} can hinder the progress of QMS implementation. Laboratory management should keep this in mind and make appropriate management decisions in hiring the laboratory staff needed to efficiently handle the workload and prevent staff turnover.

The QMS implementation strategy is another essential resource that affects the efficiency of the system’s implementation. It is very important to choose the type of implementation that best fits the laboratory. Our study shows that the use of a gradual, step-by-step QMS implementation approach, such as the World Health Organization’s ‘Laboratory Quality Stepwise Implementation’ tool⁵¹ or the US Centers for Disease Control and Prevention and the World Health Organization – Regional Office for Africa’s ‘Stepwise Laboratory Quality Improvement Process Towards Accreditation’ framework,^{29,44,45,48,54} facilitates a laboratory’s success towards accreditation. For laboratory personnel, the unassisted procedure of creating an implementation plan is often problematic and could lead to demotivation and abandonment of the quality improvement project. The aforementioned tools provide a well-structured roadmap for QMS implementation, thus mitigating the lack of personnel experience in planning. The use of the gradual step-by-step approach of QMS implementation is also one way of dealing with the problem of financial and human resource shortage.^{29,44,45,48,51,54}

Effective project management integrates the KSFs that are directly related to within-laboratory processes of QMS implementation, sustenance, and improvement, including personnel management, personnel motivation, and mentorship.

The implementation of laboratory QMS, as well as any other quality systems, requires effective human resource management and leadership, which requires laboratory leaders to have the appropriate knowledge, skills, and abilities.^{26,28,29,30,34,37,51,52} The establishment of a managerial infrastructure and delineation of management responsibilities increase the efficiency of personnel management and contribute to the success of change implementation in medical laboratories.^{28,29,30,34,37}

Forty-one percent of the analysed studies revealed personnel motivation as key to successful QMS implementation.^{26,28,30,31,37,41,42,44,45,47,48,49,53} Our results correspond to the findings of other studies that have recognised the psychological aspect of organisational changes and individual change acceptance as key components of success in healthcare innovation.^57,58

Motivating and inspiring the personnel to act towards achieving a common goal is the laboratory managers’ responsibility, and this requires strong leadership skills. The problem is that most of the laboratory leaders have not received specific training in this area.⁵⁹ At the same time, our study shows that it is important for laboratory managers to develop their leadership skills^32,52 and demonstrate their commitment to quality by establishing a shared vision and encouraging employees to do their best to improve the quality of laboratory services.^24,26,30 The lack of leadership skills among laboratory managers requires appropriate measures to be taken to solve this problem. One of the possible mechanisms to overcome this shortcoming can be mentorship.

In 27 of the 32 studies included in this review, mentorship was identified as one of the KSFs for executing laboratory service quality improvement projects and receiving accreditation.^{25,26,27,28,30,31,32,33,34,35,36,37,39,40,42,43,44,45,46,47,48,49,50,51,52,53,54} The mentor’s duty is not only to ensure the QMS implementation by planning and monitoring quality improvement activities^27,32,40,50 and increasing the staff awareness of QMS implementation mechanisms,^{27,35,36,40,45,46,50,51,54} but also to influence the attitude of laboratory managers to advocate and support all quality improvement efforts.^{28,32,33,35,46,51,52,54} Thus, the implementers may consider mentorship as one of the additional tools of laboratory QMS implementation, especially when dealing with personnel unpreparedness for change and weak leadership.

Fifty-three percent of the studies included in this review convincingly show that awareness of the essential role of laboratory medicine in a functioning healthcare system at the policy and governmental levels and the appropriate facilitation of the accreditation process of the medical laboratory are crucial factors in improving the quality of laboratory services.^{24,25,26,27,29,31,33,36,38,39,40,41,42,48,51,53,54}

Our study shows that commitment to laboratory quality improvement in LMICs must come from the top down. If the healthcare regulators are not truly dedicated to improving laboratory service quality, any efforts by individual laboratories to achieve ISO 15189 accreditation will fail. Nevertheless, some accreditation requirements could be achieved by the laboratories on their own. For example, all procedures required by the standard can be documented, internal audit processes can be implemented, quality indicators can be established, and the inventory control system for reagents and consumables can be introduced. All of this will undoubtedly lead to some improvements in laboratory quality. However, for full compliance with the standard’s requirements, laboratories are dependent on the government.

The medical laboratories in LMICs are faced with common problems such as shortage of robust supply chains for reagents and consumables,^26,31 deficit of equipment maintenance providers,^{29,31,40,47,48} lack of external quality assurance,^24,40,48 insufficient workforce capacity,^{25,29,31,32,37,40,41,42,49,55} limited number of trained laboratory personnel,^{25,26,29,30,54} etc. These difficulties make it nearly impossible to meet the standard’s requirements. It is important to realise that resolving these issues is not under the control or purview of any single laboratory management team and requires governmental intervention. If these problems are far from being resolved, expecting a laboratory to achieve an internationally recognised accreditation will often be an unreasonable initial goal.

Thus, an understanding of the policy environment would allow the implementers to have realistic expectations about the outcomes of QMS implementation. This understanding is also important to guide the choice of an implementation strategy, the development of effective timetables, and the decisions about the involvement of international or local partners.