Correlation of periscreen strip results and white cell count in peritoneal dialysis peritonitis

Diagnostic Accuracy of MMP-8 and IL-6-Based Point-of-Care Testing to Detect Peritoneal Dialysis-Related Peritonitis: A Single-Center Experience

BACKGROUND

Peritoneal dialysis-related peritonitis (PDRP) is the most common complication of peritoneal dialysis (PD), which can lead to poor outcomes if not diagnosed and treated early. We aimed to investigate the diagnostic accuracy of MMP-8 and IL-6-based point-of-care tests (POCTs) in diagnosing PDRP in PD patients.

METHODS

This retrospective chart review study was conducted at a comprehensive kidney center in Qatar. It involved all adult PD patients who underwent PDRP from July 2018 to October 2019 and for whom MMP-8 and IL-6-based POCTs were used to diagnose presumptive peritonitis. Measures of diagnostic accuracy were computed. Peritoneal fluid effluent analysis was the reference standard.

RESULTS

We included 120 patients (68 [56.7%] females, ages 55.6 ± 15.6 years, treatment duration 39.5 ± 30.4 months [range: 5-142 months]). In this population, MMP-8 and IL-6-based POCTs yielded 100% in all dimensions of diagnostic accuracy (sensitivity, specificity, positive and negative predictive values).

CONCLUSIONS

MMP-8 and IL-6-based POCTs might be helpful in the early detection of PDRP. This monocentric observation requires further confirmation in a prospective multicentric setting.

Persistent peritonitis in peritoneal dialysis: a comphrenesive review of recurrent, relapsing, refractory, and repeat peritonitis

Peritonitis is a major cause of morbidity and technique failure in patients receiving peritoneal dialysis. Complicated peritonitis that manifests as multiple or unresolving episodes is classified as refractory, recurrent, relapsing, or repeat peritonitis, and often possesses higher risk of technique failure and mortality as well as lower complete cure rates than primary or uncomplicated episodes. While these peritonitis subtypes affect a considerable portion of PD patients, details regarding their epidemiology, pathogenesis, diagnosis, clinical sequelae, and management have not yet been fully elucidated. Improved clinical awareness and understanding of complicated peritonitis subtypes is crucial to ensure optimal management for these patients; thus, we consolidate and report the pertinent findings of recent literature on these four entities.

Automated complete blood counter, urine analyzer and urine dipstick test results are correlated with thoma cell counting chamber counts in the diagnosis of dialysis related peritonitis in children

INTRODUCTION

Peritoneal dialysis is the treatment of choice for end-stage renal disease. Peritoneal dialysis related peritonitis is of great importance for patient and technical survival. The aim of our study was to evaluate the accuracy and the correlation between the three methods (complete blood count, urinalysis device, urine dipstick test) and with the reference manual method (Thoma Cell Counter Chamber).

MATERIALS AND METHODS

We retrospectively analyzed 167 peritoneal fluid samples taken from 25 patients receiving peritoneal dialysis treatment. Leukocyte counts were evaluated with Thoma Cell Counter Chamber, complete blood count, urinalysis device and urine dipstick test.

RESULTS

There was a significant positive correlation between Thoma Cell Counter Chamber and complete blood count results (Spearman's rho=0.70), between Thoma Cell Counter Chamber and urinalysis device (Spearman's rho=0.73), and between Thoma Cell Counter Chamber and urine dipstick test (Spearman's rho=0.71). Area under curve for complete blood count, urinalysis device and urine dipstick test were 0.93, 0.94 and 0.89 respectively, indicating good accuracy. Sensitivity and specificity were 89.7% and 86.7% in the complete blood count analysis (associated criterion: 130 cells/mm³). Sensitivity and specificity were 89.7% and 86.7% in the urinalysis device (associated criterion: 10 cells/HPF). Sensitivity and specificity were 79.6% and 91.4% when in the urine dipstick test analysis (associated criterion: +1 positivity). The Bland-Altman plot showed good agreement.

CONCLUSION

Automatic complete blood count and urinalysis devices have good correlation and agreement with manual method in the diagnosis of peritonitis in the pediatric age group. Urine dipstick test in the home setting can be useful for screening patients with suspected peritonitis.

Recent advances in novel diagnostic testing for peritoneal dialysis-related peritonitis

Peritoneal dialysis-related peritonitis remains a significant complication and an important cause of technique failure. Based on current International Society for Peritoneal Dialysis guidelines, diagnosis of peritonitis is made when two of the three following criteria are met: 1) clinical features consistent with peritonitis; 2) dialysis effluent white blood cell count of >100 cells/μL; 3) positive effluent culture. However, early and accurate diagnosis can still be faulty, and emphasis has been placed on improving the timeliness and accuracy of diagnosis to facilitate early effective treatment. There have been advances in the novel diagnostic tests such as point-of-care molecular tests, genetics sequencing, mass spectrometry, and machine learning algorithm with immune fingerprinting. This article will discuss the latest evidence and updates of these tests in the management of peritoneal dialysis-related peritonitis.

A non-contact device for fast screening of wound infections

Screening for wound infection relies on the expertise of the provider. Clinical diagnosis of infections based on wound swab/biopsy results often takes a few days and may not assess the full wound. There is a need for a non-invasive tool that can quickly and accurately diagnose wound infection. Leukocyte esterase strips are used to identify various infectious diseases. However, it is not clear whether infected wounds also have elevated leukocyte esterase activities as compared with non-infected wounds. To achieve the objective, a device was developed to detect elevated leukocyte esterase activities in wounds by measuring wound exudates adsorbed onto wound dressings in 3 minutes. The efficacy of the device in assessing leukocyte esterase activities across various chronic wounds was tested. Such measurements were unaffected by the type of underlying wound dressing. By correlating the device outputs with clinical adjudication of infection, we found that this device had high positive predictive values for diagnosing wound infection in a wide variety of chronic wounds. In addition, a positive device output increases the probability of detecting infected wounds, while the negative device output reduces the probability of detecting infected wounds. This rapid non-contact and disposable diagnostic tool may serve as a rapid and accurate indication of infection in the chronic wound.

Evaluation of a new rapid-diagnostic test for peritonitis in peritoneal dialysis: the PERIPLEX® device

In 2017, the British company MOLOGIC developed a new rapid-diagnostic test (PERIPLEX®) for the diagnosis of peritonitis in patients undergoing peritoneal dialysis. This single-use test is based on the detection in dialysate of two biomarkers of bacterial infection: Interleukin-6 (IL-6) and matrix metalloproteinase-8 (MMP-8). The test was evaluated in a prospective multicenter study including 10 centers from the RDPLF (French Language Peritoneal Dialysis Registry). A total of 184 tests were performed; 86 tests were negative and 98 were positive. 85 peritonitis were confirmed. There were no false-negatives, and 13 false-positives. Of the 13 false-positives, 7 of them were for sepsis without peritonitis, or peritoneal inflammation. The performance of the test is considered excellent: sensitivity 100%, specificity 86.9%, positive predictive value 86.7%, negative predictive value 100%. In this study, a negative test can formally rule out the diagnosis of peritonitis.

Peritoneal dialysis-related infections recommendations: 2016 update. What is new?

In 2016, the International Society of Peritoneal Dialysis (ISPD) published guidelines that focus on the importance of both prevention and treatment of peritonitis. For once more, the need for annual reporting of peritonitis rates and recording of peritonitis and exit-site infections, isolated microorganism and antimicrobial susceptibilities as a central component of a quality improvement program is highlighted. Data on new antibiotic regimens, techniques for microorganism isolation and peritoneal dialysis solutions are included. Training of both peritoneal dialysis nurses and patients seems to be crucial, while the modifiable risk factors for peritonitis seem to be of great interest. In this article, we record the changes in the last ISPD (2016) guidelines compared to the previous ones published in 2010.

The Periscreen Strip Is Highly Efficient for the Exclusion of Spontaneous Bacterial Peritonitis in Cirrhotic Outpatients

OBJECTIVES

We aimed to assess the performance of a new strip (Periscreen) for the rapid diagnosis of spontaneous bacterial peritonitis (SBP).

METHODS

Ascitic fluid (AF) of cirrhotic patients hospitalized between March 2014 and August 2015 was independently tested by two readers using the new strip, which has four colorimetric graduations (negative, trace, small, and large). SBP was diagnosed on neutrophils in ascites>250/mm³. Ascites not related to portal hypertension were excluded.

RESULTS

Overall, 649 patients from 21 French centers were included and 1,402 AF (803 AF samples from 315 outpatients and 599 samples from 334 inpatients) were assessed. Eighty-four AF samples (17 AF in 9 outpatients and 67 AF in 31 inpatients) were diagnosed as SBP. The prevalence of SBP was 6% (2.1% in outpatients vs. 11.2% in inpatients; P<0.001) and 7.2% in patients with symptoms suggestive of SBP (3% in outpatients vs. 11.3% in inpatients; P<0.001). The κ value for inter-reader agreement was 0.81 (95% confidence interval: 0.77-0.84) when using the "trace" threshold. Considering discordant results (n=131) as positive to interpret the diagnostic performance of the strip at the "trace" threshold, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 91.7, 57.1, 12.0, and 99.1%, respectively. At this "trace" threshold, sensitivity and NPV were both 100% in outpatients, and 89.5 and 97.9% in inpatients, respectively. At the "small" threshold, sensitivity, specificity, PPV and NPV were 81.0, 85.9, 25.9 and 98.7%, respectively.

CONCLUSIONS

The Periscreen strip is a rapid and highly efficient tool for excluding SBP in the outpatient setting.