Ascitic calprotectin as a useful marker in the diagnosis of spontaneous bacterial peritonitis in adults

Background Ascitic fluid polymorphonuclear leucocyte count (PMN) is known to be the gold standard for spontaneous bacterial peritonitis (SBP) diagnosis. The aim of this work was to assess ascitic calprotectin for SBP diagnosis. Serum C-reactive protein (CRP), high sensitivity C-reactive protein (hsCRP), nitrous oxide, ascitic PMN, ascitic leucocyte esterase and ascitic calprotectin were measured. Results The average age of our patients was 55.25 ± 7.89 years, mostly males ( n = 51, 63.8%), anti-HCV antibodies were positive in ( n = 61, 76.3%). Sixty-four patients (80%) were Child-Pugh C and their average MELD was 24.29 ± 8.06. Patients with SBP had statistically significant higher median MELD score (26.5 vs. 19) and higher average Child-Pugh score (12.18 ± 1.74 vs. 10.5 ± 1.97). Forty patients had SBP and 40 patients were without SBP. Both the serum and ascitic nitrous oxide did not differ statistically between patients with and without SBP. In contrast, patients with SBP had higher median serum CRP (49 vs. 12 mg/dL), hsCRP (58,000 vs. 23,750 ng/dL) and ascitic calprotectin (7.57 vs. 1.1 ng/mL). The ascitic leucocyte esterase test was positive in 95% of SBP patients in contrast to 2.5% patients without SBP. Ascitic calprotectin >2 ng/mL had 90% sensitivity, 92.5% specificity, 92.3% positive predictive value and 90.2% negative predictive value. MELD, CRP, hsCRP and ascitic calprotectin are independent predictors of SBP. Conclusion Ascitic calprotectin is a useful marker for SBP diagnosis.