Clinical usefulness of procalcitonin/albumin and blood urea nitrogen/albumin ratios for the early detection of bacteremia

Background: Early prediction of bacteremia is important because sepsis may develop if bacteremia is not treated in time. We aimed to determine whether blood tests are clinically useful in predicting gram-negative versus gram-positive bacteremia. Methods: We retrospectively analyzed the medical records of 16,569 patients who underwent blood culture testing among those who visited St. Mary’s Hospital of Uijeongbu, Catholic University from January 1, 2018 to December 31, 2018. After excluding 15,580 patients with insufficient data for analysis, the total study population was 989. Results: In the multivariable logistic regression analysis for gram-negative bacteremia, after adjusting for major variables, procalcitonin (odds ratio [OR] 1.02, P < 0.001), high-sensitivity C-reactive protein (OR 1.03, P = 0.010), and albumin (OR 0.55, P = 0.010) were significant. In the same model, lactic acid (OR 1.08, P = 0.010), blood urea nitrogen (BUN) (OR 1.02, P = 0.010), and albumin (OR 0.50, P = 0.005) were significant for gram-positive bacteremia. We constructed blood indicators by combining blood tests that were significant in multivariable logistic regression analysis. Comparing the area under the curve (AUC) of the receiver operating characteristic curve, the AUC of the procalcitonin/albumin ratio in gramnegative bacteremia was significantly higher than that of procalcitonin (0.846 vs. 0.837, P = 0.005), and the AUC of the BUN/albumin ratio in gram-positive bacteremia was significantly higher than that of BUN (0.709 vs. 0.679, P = 0.007). Conclusion: The procalcitonin/albumin ratio is expected to be helpful in the early prediction of gram-negative bacteremia, whereas the BUN/albumin ratio in the early prediction of grampositive bacteremia.