## 4 Research and Project Aimed at Developing Modules of a Classification and Expert System
### Diagnosis of FSGS Module  
The diagnosis module of the expert system (see Figure 2) is designed to provide a structured framework for the accurate and timely identification of focal segmental glomerulosclerosis in patients.  
It integrates various diagnostic elements, including clinical assessment, laboratory results, and histopathological evaluation, to ensure comprehensive disease evaluation. The module's primary function is to assist clinicians in confirming the diagnosis of FSGS, stratifying the disease severity, and identifying any potential secondary causes or associated risk factors:  
Patient history: The first step in the diagnosis process involves a thorough patient history to identify clinical factors suggestive of FSGS. This step is essential as it helps establish a baseline understanding of the patient's overall health and potential underlying conditions that could predispose them to glomerular diseases. Key elements in the history include:  
* Infections: chronic bacterial or viral infections can lead to glomerulopathy and contribute to FSGS.
* Chronic inflammatory diseases: conditions like rheumatoid arthritis can trigger kidney inflammation and glomerular damage.
* Autoimmune disorders: diseases such as systemic lupus erythematosus (SLE) are linked to kidney inflammation and nephritis.
* Cancer: some cancers are associated with secondary glomerulopathies, either through direct kidney involvement or treatment-related nephrotoxicity.
* Diagnostic tests: After gathering a comprehensive patient history, the next critical step involves performing diagnostic tests to confirm the presence of FSGS and assess its severity. The system recommends a set of standard tests to evaluate renal function and detect biomarkers indicative of FSGS. These include:
* Kidney function tests: serum creatinine, eGFR, and urea levels to assess kidney function and any decline in filtration capacity.
* Proteinuria assessment: quantification of proteinuria, which is a hallmark feature of FSGS, through 24-h urine collection or urine protein-to-creatinine ratio (PCR).
* Biomarkers: specific biomarkers such as anti-PLA2R antibodies, which can help differentiate between primary FSGS and secondary forms of glomerulonephritis.
* Kidney biopsy: Kidney biopsy remains the gold standard for diagnosing FSGS. In cases of atypical presentation or when non-invasive tests yield inconclusive results, a biopsy  
Figure 2: Overview of the diagnosis module of a system.  
allows for direct visualization of glomerular changes. The histopathological evaluation typically reveals characteristics such as segmental sclerosis, foot process effacement, and podocyte injury, which are diagnostic of FSGS. The expert system includes guidelines on biopsy interpretation, helping clinicians differentiate between primary and secondary forms of FSGS based on histopathological features, and determining whether further testing for secondary causes, such as viral infections or autoimmune diseases, is warranted.
* Risk assessment: An important aspect of the diagnosis module is the evaluation of the patient's risk for progression to end-stage renal disease (ESRD) or chronic kidney disease stage 5 (CKD5). The system incorporates clinical factors such as proteinuria levels, eGFR, and other relevant biomarkers to assess the likelihood of rapid disease progression.  
The diagnosis module is seamlessly integrated into the broader framework of the expert system, allowing for a smooth progression from initial assessment through to the confirmation of FSGS. One example of the system screens for biopsy decision support is included in Figure 3. The system's modular design ensures that each diagnostic step is logically sequenced, with clear decision points that direct the clinician towards the most appropriate diagnostic test or treatment intervention. The user-friendly interface facilitates the clinician's workflow, providing step-by-step guidance and immediate feedback based on input data.