Is a peritoneal white blood cell (WBC) count of 577 considered elevated?

From the Guidelines

A peritoneal white blood cell (WBC) count of 577 cells/mm³ is considered elevated and suggests peritoneal inflammation or infection. According to the most recent and highest quality study 1, a WBC count of 250 cells/mm³ or higher is indicative of an elevated count, which may represent evidence of failure of the first line of defense, the peritoneal macrophages, to kill invading bacteria. This elevation may indicate conditions such as spontaneous bacterial peritonitis (SBP), secondary peritonitis, or peritoneal inflammation from other causes.

Key Considerations

• The clinical context is crucial for interpretation, with symptoms like abdominal pain, fever, or underlying conditions like cirrhosis influencing the significance of this finding.
• Further evaluation is necessary, including additional peritoneal fluid tests like neutrophil count, culture, protein levels, and albumin gradient.
• If SBP is suspected, empiric antibiotic therapy (typically a third-generation cephalosporin like ceftriaxone 1-2g IV daily) might be initiated while awaiting culture results, as delaying treatment until the ascitic fluid culture grows bacteria may result in the death of the patient from overwhelming infection 1.
• The ascitic fluid PMN count is more rapidly available than the culture and appears to be accurate in determining who really needs empiric antibiotic treatment 1.

Management

• Patients with ascitic fluid PMN counts of 250 cells/mm³ or higher in a clinical setting compatible with ascitic fluid infection should receive empiric antibiotic therapy 1.
• The elevated WBC count should be considered alongside other laboratory findings and the patient's clinical presentation for proper diagnosis and management.
• In some patients, infection is detected at the bacterascites stage before there is a neutrophil response, i.e., 250 cells/mm³; this has been labeled monomicrobial nonneutrocytic bacterascites, and patients with bacterascites who do not resolve the colonization and who progress to SBP have signs or symptoms of infection at the time of the paracentesis that documents bacterascites 1.

From the Research

Peritoneal White Blood Cell Count

• A peritoneal white blood cell (WBC) count of 577 is considered elevated based on the studies reviewed 2, 3.
• The optimal cutoff for peritoneal fluid WBC count in predicting peritonitis is debated, with some studies suggesting a cutoff of 79 cells/μL 2 and others recommending a higher cutoff of 230/μL 3.
• A WBC count of 577 exceeds these recommended cutoffs, indicating a potential infection or inflammatory response.

Comparison to Study Findings

• In one study, a patient with eosinophilic peritonitis had a WBC count of 1,480 cells/mm3 in their peritoneal dialysis effluent 4.
• Another study reported a WBC count of 500 cells/mm3 in a patient with idiopathic eosinophilic peritonitis 5.
• A WBC count of 577 is lower than the counts reported in these studies, but still indicates an elevated level of white blood cells.

Clinical Implications

• An elevated peritoneal WBC count can indicate peritonitis, a common complication of peritoneal dialysis 6, 2.
• Clinical presentation, dialysis effluent culture, and WBC count are important factors in diagnosing peritonitis 3.
• Further evaluation and monitoring are necessary to determine the cause of the elevated WBC count and to guide appropriate treatment.