1. Introduction

Laboratory diagnostics is one of the key components of the modern healthcare system, providing up to 60-70% of objective information necessary for diagnosing, choosing treatment tactics, and evaluating the effectiveness of therapy [1,2]. The quality of laboratory tests directly affects the patient's safety, clinical effectiveness, and economic feasibility of medical care [3]. In the Republic of Uzbekistan, within the framework of the implementation of the Healthcare Development Strategy for 2021-2025 and subsequent stages of reform (including Presidential Decree No. PP-311 dated 05.09.2024 and measures to create 198 centralized inter-district laboratories by 2030), special attention is paid to the modernization of laboratory diagnostic services (LDS), the transition to centralized models, and the introduction of unified quality management standards [4,5]. The Khorezm region is characterized by a number of specific features that significantly affect the organization and quality of laboratory diagnostics: - a significant share of the rural population (about 75%) and the concentration of medical institutions; - high workload on district laboratories in conditions of limited access to modern equipment and reagents;

- climatic factors (high temperature and humidity in the summer period), increasing the risk of pre-analytical errors during the transportation of biomaterial; - persisting fragmentation of the laboratory network, especially in the northern districts of the region;

- Shovot, Khankin (Khonka), Gurlen, and Yangiarik.

Despite positive trends (implementation of laboratory information systems in a number of quality assessment departments, participation in external quality assessment programs), significant problems remain in the indicated districts: - high percentage of pre-analytical defects (from 2.5 to 4.5% depending on the district); - insufficient participation in external quality assessment programs (EFA) - from 68% to 92% in 2024-2025; - uneven equipment and personnel training; - lack of a unified regional quality indicator monitoring system. International standards (primarily ISO 15189:2022 "Medical Laboratories. Quality and Competence Requirements") and WHO recommendations emphasize the need for a comprehensive approach to quality management covering all aspects of the laboratory process - pre-analytical, analytical, and post-analytical [6,7]. At the same time, regional adapted quality assessment systems that take into account local logistics, personnel, and climate characteristics are gaining special value.

Research objectives

Develop and scientifically substantiate a system for assessing the quality of the laboratory diagnostic service of the Khorezm region based on international standards and quality indicators adapted to regional conditions.

2. Materials and Methods

The quality assessment system is developed based on: international standard ISO 15189:2022 "Medical Laboratories.

Requirements for quality and competence"; WHO recommendations on the laboratory quality management system; the concept of a complete laboratory process (Total Testing Process) with an emphasis on the pre-analytical (up to 68% of errors), analytical, and post-analytical phases.

Research methods

Ø Adaptation of IFCC WG-LEPS quality indicators;

Ø External Quality Assessment (QQA) through interlaboratory comparison;

Ø Calculation is sigmo-metric (σ = (TEa - Bias) / CV);

Ø Descriptive Statistics and Trend Analysis (Excel, SPSS).

Object and scope of research. Analysis of the work of 12 clinical and diagnostic laboratories of the Khorezm region (including CROs of the Shavatsky, Khankinsky, Gurlensky, Yangiaryk districts) for 2024-2025. Data obtained by:

- audit according to the checklist ISO 15189;

- monthly monitoring of 24 quality indicators;

- results of participation in VOC programs;

- analysis of reports from the regional health department.

Observation periodJanuary 3, 2024 - December 2025. The study was conducted in accordance with the requirements of the reform of the laboratory service of Uzbekistan (PP-311 dated 05.09.2024 and others) and national adaptations of quality standards.

3. Results and Discussion

Results of the assessment of the quality of laboratory diagnostic services in the Shavatsky, Khankinsky, Gurlensky, and Yangiaryk districts (2024-2025).

Table 1. Economic indicators (2025 compared to 2024)

A comparative analysis of the activities of central district hospitals (CRS) in four districts of the northern part of the Khorezm region was conducted (the sample covered 100% of CRS laboratories in these districts). The data were obtained as a result of audits, monthly monitoring of quality indicators, and participation in external quality assessment programs (EFA) for the period from January 2024 to December 2025.

Table 2. Comparative indicators of the quality of laboratory services in selected districts (average values for 2025)

The Shavatsky district showed the best results (92% participation in the VOC in 2025, an increase of 19 percentage points since 2023) thanks to a higher level of equipment and regular training of personnel.

The lowest indicator (71%) is in the Yangiaryk district, which is due to problems with the logistics of sample delivery in conditions of remoteness from the regional center and the shortage of thermal containers.

Scientific justification: a low level of participation in the VOC directly correlates with an increased percentage of pre-analytical defects (r = -0.87, p < 0.01) and lower values of the sigma metric. Districts with ≥ 85% participation in VOC demonstrate a sigma level ≥ 4σ on key tests, which complies with CLSI and IFCC recommendations.

Economic efficiency of implementing a quality assessment system

According to preliminary calculations (based on data on the quantity of research and the cost of reagents in 2025):

A 1% reduction in pre-analytical defects allows saving an average of 8-12 million soums per year per district (through reduction of repeated sampling and consumables).

In the Shovot district, savings amounted to ≈ 18.4 million soums in 2025.

In the Yangiarik district - only 6.2 million soums (due to high marriage rates).

Total potential effect for 4 districts when bringing all indicators to target values: 42-56 million soums per year.

Implementation mechanism

1. Stage 1 (Diagnostics): audit of the current state of laboratories according to the checklist for compliance with the requirements of ISO 15189;

2. Stage 2 (Standardization): development of unified pre-analytics protocols for nurses of polyclinics and hospitals of the region;

3. Stage 3 (Monitoring): monthly data collection on indicators through a digital platform with trend visualization;

4. tage 4 (Feedback): quarterly meetings with laboratory managers to analyze deviations and corrective actions.

Adaptation to the regional conditions of the Khorezm region

Taking into account the specifics of the region (rural distribution of the population, hot climate affecting sample stability), the system includes additional indicators:

- Temperature regime of sample transportation (thermocontainer control);

- Delivery time of samples from remote districts (Shavatskiy, Khazarasp) to the central laboratory of the city of Urgench;

- Training of medical personnel in pre-analytical procedures (at least 8 hours per year).

4. Conclusions

1. A quality assessment system for the laboratory diagnostic service of the Khorezm region, integrating the requirements of the ISO 15189 standard, quality indicators by phases of the laboratory process, and a methodology for quantitative assessment through sigma metrics, has been scientifically substantiated.

2. The proposed model of 24 indicators allows for the identification of bottlenecks in laboratory work, especially in the pre-analytical phase, where up to 68% of errors are concentrated.

3. The system is adapted to the regional conditions of the Khorezm region and can serve as a basis for creating a unified digital register of the quality of laboratory services within the framework of the national reform of the laboratory service of Uzbekistan.

4. For successful implementation, it is necessary: to create a regional center for external quality assessment on the basis of the Republican Emergency Medical Center in the city of Urgench, to train personnel according to pre-analytics standards, and to implement a unified information system for monitoring indicators.