The diagnosis of spontaneous bacterial peritonitis is based on a manual count of ascitic fluid polymorphonuclear cells.
This procedure is operator-dependent and lysis of polymorphonuclear cells during transport to the laboratory may lead to false-negative results.
Furthermore, ascitic fluid culture is insensitive and leads to delays in diagnosis.
Dr Mansour Parsi and colleagues from Ohio, USA assessed the utility of ascitic fluid lactoferrin for the diagnosis of spontaneous bacterial peritonitis.
The research team identified a cut-off level that can be used for future development of a rapid bedside test.
A total of 218 consecutive ascites samples from 148 patients with cirrhosis at 2 tertiary care medical centers were examined for polymorphonuclear cells count, bedside culture, and lactoferrin concentration.
Ascitic fluid lactoferrin concentrations were determined using a polyclonal antibody-based enzyme-linked immunosorbent assay.
An ascitic fluid polymorphonuclear cells count of 250 cells/mL or greater with or without a positive culture was used for diagnosis of spontaneous bacterial peritonitis.
The research team found that 22 samples fulfilled diagnostic criteria for spontaneous bacterial peritonitis.
|The sensitivity of the assay for diagnosis was 96%|
The team noted that samples with spontaneous bacterial peritonitis had a significantly higher lactoferrin concentration compared with non-spontaneous bacterial peritonitis samples.
By using a cut-off level of 242 ng/mL, the sensitivity and specificity of the assay for diagnosis of spontaneous bacterial peritonitis were 96% and 97%, respectively.
The area under the receiver operating characteristic curve was 0.98.
Dr Parsi’s team commented, “Ascitic fluid lactoferrin can serve as a sensitive and specific test for diagnosis of spontaneous bacterial peritonitis.”
“Qualitative bedside assays for the measurement of ascitic fluid lactoferrin can be developed easily and may serve as a rapid and reliable screening tool for spontaneous bacterial peritonitis in patients with cirrhosis.”