Usefulness of presepsin / creatinine ratio as a new index that corrects for renal function

Background : Presepsin (P-SEP) is a highly specific sepsis marker, and its fluctuation with respect to advanced renal impairment or sample agitation has not been fully investigated. We evaluated several renal function-corrected P-SEP indices to establish a simple index and its reference range. Methods : Blood samples for P-SEP measurement were collected with minimal agitation. P-SEP levels were measured using the rapid automated immunoanalyzer "PATHFAST." This study included 85 chronic kidney disease (CKD) patients, 65 healthy volunteers, and 4 sepsis patients. Results : Patients stratified by estimated glomerular filtration rate (GFR) had significantly higher P-SEP levels for CKD stage G3, especially the advanced GFR stage. We evaluated presepsin / creatinine (P-SEP / CRE) and P-SEP / eGFR ratios as possible indices for renal function. The P-SEP / CRE ratio exhibited no increase correlating with the GFR stage and was identical in the normal and CKD groups ;  P-SEP / eGFR decreased if GFR stage worsened. The P-SEP / CRE ratio became significantly higher in sepsis patients and was a more useful index with a reference range of 67-263. Conclusions : P-SEP levels were inversely correlated with renal function, indicating the necessity to consider the influence of renal impairment in CKD patients. The P-SEP / CRE ratio is helpful for sepsis diagnosis, even in patients with renal impairment. J. Med. Invest. 68 : 105-111, February, 2021.