A HemoCue Novel Technology Product for -Part Differentiation of Leukocytes Point-of-Care Stellan Lindberg, M Sc Medical Director HemoCue AB Kuvettgatan 1 SE-262 71 Ängelholm Sweden Stellan.Lindberg@hemocue.se
HemoCue WBC DIFF System - the first -part Diff WBC counter for POCT 1. Fill the microcuvette with 1 µl blood 2. Push the button for patient test and place the microcuvette in the cuvette holder 3. The results will be displayed within five minutes
A Photo Microscope is used to detect the stained white cells Chemistry in the microcuvette: Saponin Haemolyses the red blood cells Methylene Blue stains the nucleus of the white cell Volume appr..2 µl Cuvette chamber with a fixed thickness and a defined detection area gives a fixed volume for enumerations of stained cells The volume is well specified by having: a specific measurement area of the microcuvette tight tolerances of the cavity depth in the microcuvette
The cavity is analyzed in separate layers to enable detection of cells at different depths Cavity depth 14 µm The camera lens moves in small steps taking several images through the cavity of the cuvette All cells in all images will be cut out Identifying when each cell is in focus Mount the focused cells into one image Count WBC and differentiate on this final image
Photoshoping of each cell in the images Neutrophils Lymphocytes Monocytes Transferring characteristics into mathematical algorithms Eosinophils Basophils WBC DIFF uses over 3 features and state-of-the-art image analysis technology
WBC DIFF can identify and flag pathological cells Sample with 87, % blast cells Sample with 2, % myelocytes and 4,3 % metamyelocytes
Prediction model object Half Sensitivity and specificity Pathological classification tree Normal cells classification tree Basophils Blurred Trash Multiple Debris Eosinophils Neutrophils Lymphocytes Pathology flag Sensitivity: 83.2 % Specificity: 96.1 % Meta Myelo Blast cells Monocytes Sensitivity abnormal morphology: 88.1 % Ref: CLSI H2-A2 Pathology flag part diff
Advanced Internal QC System 1. At power up ( Self test ): Test of electronics and software Blanking test (Quality of light, check for dirt in the optics) 2. Between samples: Blanking test 3. For each sample: Correct sampling detection Bad area detection Out of focus detection Air bubble detection Poor light intensity Bad cell distribution
The results from WBC DIFF correlate well to common laboratory cell counters Total Leukocytes Neutrophils Lymphocytes Monocytes Eosinophils Siemens ADVIA 212 3 2 2 1 1 y =.93x -.17 r =.993 n = 119 3 2 2 1 1 y =.87x +.2 r =.994 n = 11 4 3 2 1 y =.96x +.18 r =.94 n = 11 3 2 1 y = 1.2x -.16 r =.69 n = 11 1, 1,, y =.92x +.2 r =.76 n = 11 1 1 2 2 3 Leukocytes x1 9 /L Siemens ADVIA 212 1 1 2 2 3 Neutrophils x1 9 /L ADVIA 212 1 2 3 4 Lymphocytes x1 9 /L ADVIA 212 1 2 3 Monocytes x1 9 /L ADVIA 212,,, 1, 1, Eosinophils x1 9 /L ADVIA 212 Beckman Coulter LH7 3 2 2 1 1 y =.98x -.23 r =.996 n = 116 1 1 2 2 3 Leukocytes x1 9 /L Beckman Coulter LH7 2 2 1 1 y =.94x +.2 r =.994 n = 84 1 1 2 2 Neutrophils x1 9 /L Beckman Coulter LH7 6 4 2 y =.99x +.1 r =.96 n = 84 2 4 6 Lymphocytes x1 9 /L Beckman Coulter LH7 3 2 1 y =.63x +.1 r =.8 n = 84 1 2 3 Monocytes x1 9 /L Beckman Coulter LH7 1, 1,, y = 1.13x +, r =.86 n = 84,,, 1, 1, Eosinophils x1 9 /L Beckman Coulter LH7 Sysmex XS-1i 3 2 2 1 1 y =.97x -.18 r =.997 n = 114 1 1 y =.98x +. r =.989 n = 92 6 4 2 y = 1.1x -.1 r =.98 n = 92 x19/l HemoCue WBC DIFF 3 2 1 y =.1x +.1 r =.76 n = 92 1,, y = 1.11x -.2 r =.91 n = 92 1 1 2 2 3 Leukocytes x1 9 /L Sysmex XS-1i 1 1 Neutrophils x1 9 /L Sysmex XS-1i 2 4 6 Lymphocytes x1 9 /L Sysmex XS-1i 1 2 3 Monocytes x19/l Sysmex XS-1i,,, 1, Eosinophils x1 9 /L Sysmex XS-1i
WBC DIFF at POC fulfills a clinical unmet need in several care settings and clinical applications Emergency clinic We conclude that for clinicians who evaluate patients with a suspected severe infection in the ED, special attention should be directed to the RR, CRP, and WBC, and that low Hb may be an underestimated biomarker in this context Gille-Johnson P., et al., Scand. Journal of Infectious Diseases (212) In an emergency care setting, both lymphocytopenia and NLCR are better predictors of bacteremia than routine parameters like CRP level, WBC count and neutrophil count. Attention to these markers is easy to integrate in daily practice and without extra costs. de Jager C.P., et al., Crit Care 14 (21) Doctor s office In conclusion, the NLCR (Neutrophil to Lymphocyte Count Ratio) may serve as a simple marker for discrimination between severe bacterial and viral infections. Holub M. et al., Cent. Eur. J. Med. (212) Pediatric clinic White blood cell count can aid judicious antibiotic prescribing in acute upper respiratory infections in children Casey, J. et al, Clin Pediatr 42 (23) Psychiatric clinic Monitoring total WBC and neutrophils (NEU) with a point-of-care device during Clozapine treatment on schizophrenic patients Nielsen, J., et al., Eur. Neuropsychopharmacol. (211) Oncology clinic Monitoring before next doze of chemotherapy Price CP, et al, Point-of-care testing; 2nd ed. (24)
Conclusion The novel POCT HemoCue WBC DIFF technology is built on state-of-the art imaging technology The results from the system are accurate and precise and correlate well to laboratory cell counters both in the hands of lab technicians as well as untrained users A white blood cell count including a -part diff at the point of care will increase the availability of already well established and frequently used lab parameters Rapid and easy access will be a valuable tool for physicians in making direct and more well informed decisions in several clinical conditions
Acknowledgements: Jönsson, Inger and Nilsson, Magnus, Växjö Central Hospital Clin Chem Dept, Växjö, Sweden Wahlström, Saga, Malmö University Hospital, Clin Chem Dept, Malmö, Sweden 1 Jonasson-Bjäräng, Tomas and Johnsson, Elin, HemoCue AB, Ängelholm, Sweden 1 ) Saga Wahlström has sadly passed away since the study was done, the data has been published by permission from her clinic in Malmö