The periscreen strip is an accurate and rapid method to diagnose spontaneous bacterial peritonitis among patients...

Leukocyte esterase reagent strips may help diagnose spontaneous bacterial peritonitis (SBP), but their effective application among patients with acute-on-chronic liver failure (ACLF) remains unknown.

This study aimed to assess the performance of periscreen strips in the rapid diagnosis of SBP among patients with ACLF.

Periscreen strips were used to test 261 ascites samples taken from 251 inpatients with ACLF between January 2014 and June 2019. The colors of the reagent strip were divided into four colorimetric graduations ('negative', 'trace', 'small', and 'large'), among which 'trace' is used as the SBP detection threshold. The polymorphonuclear neutrophils (PMN) of ascites ≥250/mm3 was used as the gold standard for SBP diagnosis.

SBP was detected in 92 (35.2%) ascite samples. The ascites PMN count of 'negative' (32.5/mm3) was lower than those of 'trace' (248.2/mm3), 'small' (379.0/mm3), and 'large' (7426.0/mm3) (P < 0.001). The colorimetric graduations of the strips were positively correlated with ascites PMN count (r = 0.867, P < 0.001). Periscreen strips had 100% sensitivity, 91.1% specificity, 86.0% positive predictive value, 100% negative predictive value, 11.3 positive likelihood ratios, and 0 negative likelihood ratios. For patients with negative results judged by the gold standard, ascites white blood cells count [odds ratio (OR) = 1.007) and ascites PMN count (OR = 1.028) were independent predictors of false-positive cases.

Liver failure did not affect the diagnostic performance of periscreen strips. Therefore, these strips can efficiently and rapidly diagnose SBP among patients with ACLF.