Concordance between semi-quantitative result of the number of leukocytes measured by urine test strip (Multistix 10 SG) and quantitative result obtained by cytology of peritoneal fluid in patients on Peritoneal Dialysis

Lucía Sánchez, Unidad Académica de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
Sofía San Román, Unidad Académica de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
José Boggia, Unidad Académica de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
Cecilia Baccino, Unidad Académica de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
Ricardo Silvariño, Unidad Académica de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay

Objective: Peritoneal dialysis (PD) peritonitis is a common complication. Previous studies report an association between the presence of leukocytes in peritoneal fluid (PF) with the use of urine test strips and the cell count in PF; This study seeks to evaluate agreement between the semiquantitative result of leukocytes measured by reagent strip and the quantitative result obtained by LP cytology. Material and methods: 100 samples from 43 PD patients were included; Cytology was studied using an automated counter and urine reactive strips (Multistix 10 SG) were made from the same sample. Results: 26% were women, age 47.7±13.1 years, and 11% were diabetic. To analyze agreement between leukocyte measurement by strip and automated measurement, kappa coefficient (k) and alternative Bland and Altman analysis were used. The result showed good overall correlation. The sensitivity of the strip to make a diagnosis of peritonitis was 95.2% and the specificity was 63.6%. Conclusions: good agreement was observed between leukocyte count by reagent strip and automated cytology. The strip had good sensitivity and a high negative predictive value for the diagnosis of peritonitis. The urine strip is an effective and economical tool for the initial evaluation of peritonitis in patients on PD.

Keywords: Bacterial peritonitis. Peritoneal dialysis. Urine strips test. Leukocyte count. Peritoneal fluid cytology.