Effluent microscopy is a useful adjuvant diagnostic tool in peritoneal dialysis-associated peritonitis.

BACKGROUND

Infectious complications are the leading cause of technical failure in peritoneal dialysis (PD); however, targeted anti-infective therapy is not feasible at the onset, as effluent cultures take days and may be inconclusive. Although recommended by the guidelines, divergent positivity rates of Gram-stained effluent microscopy question the value of its usefulness. This study aimed to evaluate if microscopy of cell types serves as an additional and timely diagnostic approach.

MATERIALS AND METHODS

This single-center retrospective analysis included prevalent PD patients (n = 250) between 2007 and 2017. Automated quantitative cell count, cytological analysis of Hemacolor and Gram-stained effluent sediment, and effluent cultures were conducted during peritonitis episodes. We calculated the rate of peritonitis, positivity rate of effluent cultures, and effluent microscopy.

RESULTS

There were 155 at-risk cases of peritonitis in 662.7 years during the observation period. The culture positivity rate was 73.5%. In neutrophilic culture-negative peritonitis (CNP), effluent Gram staining yielded the identification of the microbial species in 51.6% cases. In 24.4% of CNP, effluent microscopy showed eosinophilic peritonitis, which occurred with less initial effluent leucocytes and showed better PD survival.

CONCLUSION

In PD-associated peritonitis, Gram-stained dialysate with effluent microscopy supplements culture results in CNP. Hemacolor staining is crucial for differentiating eosinophilic peritonitis, showing a divergent clinical course and outcome.