Reuters Health Information (2008-09-26): Ascitic fluid lactoferrin level an accurate indicator of bacterial peritonitis
Ascitic fluid lactoferrin level an accurate indicator of bacterial peritonitis
Last Updated: 2008-09-26 8:30:37 -0400 (Reuters Health)
NEW YORK (Reuters Health) - In patients with cirrhosis and ascites, lactoferrin concentration in ascitic fluid represents a potential new test for diagnosing spontaneous bacterial peritonitis, investigators report in the September issue of Gastroenterology.
Currently, spontaneous bacterial peritonitis in these patients is diagnosed by a polymorphonuclear (PMN) cell count of 250 or more cells per mL of ascitic fluid. As a stable byproduct of activated PMNs, lactoferrin may be a clinically useful means of rapidly diagnosing this condition.
To test this theory, Dr. Mansour A. Parsi and colleagues used a noncommercial enzyme-linked immunosorbent assay to measure lactoferrin levels in 218 consecutive ascites samples from 148 patients undergoing treatment for cirrhosis at the Cleveland Clinic, Ohio, or at Baylor University Medical Center in Dallas, Texas.
Lactoferrin concentration was significantly higher in the 22 fluid samples positive for bacterial peritonitis according to PMN counts than in the non-peritonitis samples (median 3744 vs 31 ng/mL, p < 0.001).
With a cut-off level of 242 ng/ mL, the sensitivity and specificity of lactoferrin for diagnosis of bacterial peritonitis were 95.5% and 97%, respectively.
In 21 of 22 patients, PMN counts and lactoferrin levels decreased significantly in repeat ascitic fluid samples obtained 3 to 5 days after starting antibiotic treatment.
The researchers point out that a rapid diagnostic test would expedite treatment for spontaneous bacteria peritonitis, thereby improving survival. According to their estimates, "qualitative tests able to detect lactoferrin levels in excess of a predetermined level for bedside diagnosis can be developed easily, with a cost in the range of $10 - $20."
In a related editorial, Dr. Eric R. Kallwitz at the University of Illinois at Chicago comments, "Although the initial results are promising, much work is needed before lactoferrin testing can enter the realm of clinical practice," including larger studies to verify the findings, and development and testing of a qualitative bedside assay.