To evaluate the application of a self-prepared diluent in automated fecal analysis and assess the consistency of its detection results with those of the manufacturer′s original diluent.

A total of 4 127 stool specimens were collected from inpatients at the First People′s Hospital of Tianmen between December 2023 and January 2024. Parallel testing was performed using the self-prepared and commercial diluents on the same automated fecal analyzer. Performance validation of the self-prepared diluent, including the blank test, repeatability, carryover rate, fecal occult blood (FOB) test, homogeneity, and stability was conducted according to industry standards. Differences in the detection of stool physical appearance, FOB, red blood cells (RBCs), white blood cells (WBCs), parasites, fungi, and fat globules were compared between the two diluents.

The self-prepared diluent complied with all industry standards for the evaluated performance indicators. The sensitivities for detecting stool physical appearance, FOB, WBCs, RBCs, parasites, fat globules, and fungi were 97.25%, 99.63%, 89.96%, 87.38%, 94.55%, 96.02%, and 92.86%, respectively. The specificity and accuracy both exceeded 95.00% across these parameters. High consistency was observed between the two diluents (> 95.00%), with all Kappa values > 0.850. Additionally, the self-prepared diluent reduced the reagent cost by 85 CNY per liter.

The self-prepared diluent demonstrates satisfactory homogeneity, stability, and analytical performance, with detection results highly consistent with those of the commercial diluent. Given its ease of use and significant cost-effectiveness, it holds promise for clinical application and translation.