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Abstract: FR-PO471

QuickCheck: A Point-of-Care Leukocyte Counter for PD Management

Session Information

Category: Dialysis

  • 702 Dialysis: Home Dialysis and Peritoneal Dialysis

Authors

  • Dobson, Curtis B., The University of Manchester Faculty of Biology Medicine and Health, Manchester, United Kingdom
  • Cant, Rachel, The University of Manchester Faculty of Biology Medicine and Health, Manchester, Manchester, United Kingdom
  • Barker, Michael Gordon, Microbiosensor Ltd., Manchester, United Kingdom
  • Kell, Darren, Microbiosensor Ltd., Manchester, United Kingdom
  • Kennedy, Stephnie M., Microbiosensor Ltd., Manchester, United Kingdom
  • Milner, Adam Steven, Microbiosensor Ltd., Manchester, United Kingdom
  • Jackson, Ida Mari, Microbiosensor Ltd., Manchester, United Kingdom
  • Willett, Thomas Clifford, Microbiosensor Ltd., Manchester, United Kingdom
  • Griffiths, Ryan, Microbiosensor Ltd., Manchester, United Kingdom
  • Foster, John Peter, Microbiosensor Ltd., Manchester, United Kingdom
  • Knight, Chris, School of Natural Sciences, The University of Manchester, Manchester, United Kingdom
  • Lewis, David M., Salford Royal NHS Foundation Trust, Salford, Salford, United Kingdom
  • Vardhan, Anand, Manchester University NHS Foundation Trust, Manchester, Greater Manchester, United Kingdom
  • Wilkie, Martin E., Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, Sheffield, United Kingdom
  • Govindji-Bhatt, Nishal, Microbiosensor Ltd., Manchester, United Kingdom
Background

Peritonitis is a major cause of peritoneal dialysis (PD) technique failure, and causes significant morbidity, mortality and anxiety. Cloudy effluent caused by increased leukocytes (typically neutrophils) is an early indicator, but visual assessment is unreliable. We have developed QuickCheck, a simple point-of-care device to provide an instant leukocyte count. Here we confirm which leukocytes are present in PD patients without peritonitis, and which should be detectable by the instrument. We also compare the relative performance of QuickCheck and a UK ‘gold standard’ hospital laboratory flow cytometer (Sysmex UF5000).

Methods

Leukocytes present in PD effluent were determined for 9 PD patients without peritonitis. Isolated leukocytes were stained (with CD45,CD3,CD4,CD8,CD19,CD33,CD14,CD16,CD56,CD66b,HLA-DR,CD11b,CD303 and EpCam) followed by mass cytometry to identify the leukocyte type. QuickCheck performance was compared with Sysmex using leukocytes from effluent from 6 PD patients (IRAS 294250) resuspended in filtered (cell-free) effluent to yield test concentrations (10-1000 cells/μl). The percentage error, linearity of response and bias were compared. Accuracy and precision were also calculated.

Results

Leukocytes from PD patients without peritonitis comprised many sub-types, including macrophages (47%), monocytes (11%), T-Cells (CD4+) (7%), T-Cells (CD8+) (12%), B-Cells (6%), neutrophils (12%), NK cells (0.4%). Percentage error between the QuickCheck and Sysmex was 10% across the range 10-1000 cells/μl, linearity (R2) was 0.99 and Bland-Altman analysis showed no bias (0.000). Accuracy of the Sysmex was 95.9% and QuickCheck was 90.5%. Precision for Sysmex was 5.6% and QuickCheck was 3.0%.

Conclusion

Leukocytes present in PD patients without peritonitis are diverse, and so detecting all types is important for use with initially ‘well’ patients, as infection begins to develop. QuickCheck and Sysmex both showed good correlation with each other by linearity, and neither showed appreciable bias. Independent analysis showed QuickCheck was more precise though slightly less accurate than Sysmex, but has the advantage of speed, simplicity, portability and suitability for use at point-of-care.

Funding

  • Commercial Support