To assess the performance of the Nova Max Creatinine and eGFR assay in the hands of CLIA-Waived Point-of-Care users in at least three (3) distinct Point-of-Care clinical settings on venous, and capillary blood and compare the performance characteristics to a traceable laboratory reference method (the Siemens EXL creatinine determination).

To assess the Ease of Use of the Nova Max Creatinine and eGFR Meter System in the hands of the intended CLIA-Waived Point-of-Care users.

This study is designed to evaluate the performance of the NM Meter when used by CLIAW operators in terms of both accuracy to an established reference method and precision. CLIAW operators will receive no training or prompting on how to use the NM Creatinine and eGFR Meter, operating only using the instructions found in printed labeling materials (IFU, QRG, packaging).

In determining the accuracy of the device, subjects will be tested using the NM Creatinine and eGFR Meter alongside a central laboratory reference method and the results will be compared to one another. This portion of the study is referred to as Method Comparison.

In determining the precision of the device, multiple creatinine determinations will be made with the NM Creatinine and eGFR meter using both stabilized control materials (testing over the course of 20 days) and venous whole blood specimens (tested over the course of a single day). The difference between the multiple test results will determine the device's level of precision. This portion of the study is referred to as Precision.

Inclusion Criteria:

1. Adult males or females (≥ 18 years of age)
2. CKD Stage 1 (healthy)
3. CKD Stages 2-4
4. Subjects willing and able to consent to participating in the study.
5. Subjects whose pre-screen creatinine and eGFR value, if performed, is deemed valuable to the study.

Exclusion Criteria:

1. Subjects unable to consent to participating in the study.
2. Subjects possessing a cognitive disorder or other condition, which, in the opinion of the investigator, would put the person at risk or seriously compromise the integrity of the study.

Subjects will be identified via medical records for history of CKD or compromised kidney function and contacted to participate in this study. Study site personnel will provide details regarding the study (requirements, test procedure, subject rights) to obtain informed consent from the subject.

Potential subjects will be screened using the protocol inclusion and/or exclusion criteria. Adult subjects (≥ 18 years of age) with creatinine levels spanning the entire AMR of the NM Creatinine and eGFR Meter will be recruited for the study.