BACKGROUND: This study was designed to increase the precision and clinical significance of serum creatinine (Cr) measurements by refining the detection methodology through comprehensive laboratory automation and by employing the urea/creatinine ratio(UCR) to detect and mitigate drug interference. METHODS: We measured the serum Cr concentration via the Siemens sarcosine oxidase enzymatic (SOE) assay. A substantial dataset comprising nearly 2 million records from 98,377 individuals was extracted to form the foundational database for serum UCR analysis. Using the Refine R package, we delineated the reference intervals for UCR. Our laboratory's automated system adeptly identified samples exhibiting aberrant UCR values, prompting a re-evaluation of Cr levels via the Siemens Jaffe (improved alkaline picrate) assay. These Cr measurements were subsequently corroborated against Beckman and Ortho SOE assays and benchmarked against liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS), the reference standard. RESULTS: The reference interval for the serum UCR ranged from 0.047 to 0.143(90% CI 0.046-0.048, 0.135-0.148).Among the 58 abnormal samples assessed, the mean deviation in Cr detection for the Siemens, Beckman, and Ortho SOE assays relative to the LC-IDMS/MS results were -61.05%,-53.97%, and -17.18%, respectively. The Siemens Jaffe (improved alkaline picrate) assay revealed a mean deviation of -3.10% compared with that of LC-IDMS/MS. These findings indicate that the improved alkaline picrate assay can accurately reflect the true Cr levels in serum samples affected by calcium dobesilate or etamsylate interference. CONCLUSION: The implementation of an automated UCR-based screening protocol has been shown to efficiently pinpoint samples with drug-related interference. This strategic approach not only decreases clinical risk but also guarantees the fidelity of serum Cr measurements without undermining the overall productivity of the laboratory's automated workflow.