The goal of this clinical performance study is to evaluate the accuracy and usability of the Eaglenos Creatinine Test System（referred to as EG）, a point-of-care testing (POCT) system that consists of a handheld device and its associated creatinine test strips, intended for home use by laypersons with non-dialysis-dependent kidney disease.

The main questions it aims to answer are:

1. How consistent are creatinine measurements from the investigational creatinine test system compared with the clinical standard method?
2. How usable is the Creatinine Monitoring System for laypersons in a home setting?

Researchers will compare creatinine results obtained with the investigational creatinine test system (fingerstick capillary whole blood) to those from a Cobas biochemical analysis system（referred to as Cobas) (venous plasma) to determine whether the investigational device provides accurate and reliable measurements.

Participants will:

1. Provide a venous blood sample for comparative testing.
2. Perform self-testing using the Creatinine Monitoring System without prior training.
3. Complete a usability questionnaire about their experience with the investigational creatinine test system.

This clinical performance study is designed to evaluate the accuracy and usability of the Creatinine Monitoring System under controlled conditions. Prior to study initiation, the investigational device, comparator device, and associated instruments will be verified to ensure calibration and proper function. All study personnel will undergo training on the protocol, informed consent procedures, and case report form (CRF) completion, and a kick-off meeting will be held to clarify roles and responsibilities.

Participants will be enrolled strictly according to the predefined inclusion and exclusion criteria. Each subject will be assigned blinded identification numbers, including subject numbers, tester numbers, and venous blood sample numbers, to minimize bias. Venous blood will be collected for hematocrit testing and comparator analysis. Following blood collection, layperson participants will receive the complete investigational device package, including the instructions for use (IFU) and relevant labeling, and will perform self-testing without any prior training or assistance. Self-testing will take place in a separate room to avoid influence from previous participants. Disinfection of the handheld electrochemical meter will be performed using CLOROX HEALTHCARE Bleach Germicidal Wipes as specified in the user manual.

After completing self-testing, layperson participants will assess the usability of the device by filling out a structured questionnaire, focusing on IFU readability and ease of use. In parallel, trained observers will complete an observer questionnaire to document any operational errors or deviations during the testing process.

Once all testing is complete, results will be unblinded. Study data will be collected and verified by the clinical research associate (CRA) for completeness and accuracy of the CRFs. Statistical analyses will then be performed by qualified statisticians on the finalized dataset, and findings will be summarized in a clinical performance study report.

Importantly, this study is observational in nature. The investigational and reference creatinine measurements are performed for research purposes only. Clinical diagnosis, treatment, and patient management are not affected by the investigational device results, and all medical care is provided according to routine clinical practice.

Inclusion Criteria:

• Abnormal creatinine levels or suspected kidney disease;
• Aged 18 and above, gender is not limited;
• Voluntarily participate in this clinical study by signing the informed consent form.

Exclusion Criteria:

• The HCT range is not within 25-65%;
• Severe mental illness or other conditions that make the patient unable to cooperate;
• Inability to read or write in English language;
• Incomplete subject information (including but not limited to gender, age, education level, clinical diagnosis information; etc.);
• Previous experience with this creatinine monitoring system or similar self-monitoring devices (including but not limited to those for glucose, ketones, total cholesterol, etc.);
• Other conditions that, in the opinion of the investigator, make participation in this clinical trial inappropriate.

Include at least 80% patients with varying stages of non-dialysis dependent kidney disease, as well as a small group (e.g.<20 %) of healthy volunteers and dialysis-dependent kidney disease patients, to cover the reference interval of the creatinine concentration. All subjects should be naive to this creatinine monitoring system and the similar self-monitoring devices (including but not limited to glucose, ketone, total cholesterol, etc.).

All collected lPD

Starting 6 months after publication

Data will be made available to qualified researchers upon submission of a research proposal and executionof a data use agreement. Data access will be granted after the final study results are published and after anethical review by the institution's ethics board. Data sharing will be coordinated via email. Qualifiedresearchers can contact xu_tingting@eaglenos.com to request access to the data.