Contributions
Abstract: PB2352
Type: Publication Only
Background
The cobas m 511 integrated hematology analyzer is a novel slide-based system that performs a CBC, WBC differential, reticulocyte count, and nucleated RBC count using digital analysis of a microscope slide.
Aims
To assess the accuracy of low platelet (PLT) counts on the cobas m 511 compared with the Sysmex® XN-10 Automated Hematology Analyzer and BD FACSCanto™ Flow Cytometer in a single-center study.
Methods
Residual whole blood samples (n=115) in the PLT range 1-505 x103/µL (based on flow cytometery using CD61, CD41a, and CD42b antibodies) were randomly processed on each system. Sysmex samples were set to automatically reflex to PLT-F function, which is marketed as more reliable for thrombocytic or problematic samples than the standard impedance PLT-I function. Three analyses were performed: cobas m 511 and Sysmex Analyzer versus flow cytometer (reference), and cobas m 511 versus Sysmex Analyzer (reference). Data were compared using three thresholds and results included if a valid PLT result was obtained on both systems.
Results
All low PLT samples had valid results with the cobas m 511 and flow cytometry. Two (1.7%) samples were flagged with the Sysmex Analyzer (PLT-F) indicating unreliable results. The cobas m 511 demonstrated excellent accuracy compared with flow cytometry, with ≥93.6% sensitivity, specificity, and agreement, and good accuracy compared with Sysmex Analyzer (Table 1). Attempts were made to also study results for the Sysmex Analyzer PLT-I function; however, the vast majority of samples (100% for PLT counts ≤10, 80% for PLT 11–20, and 28% for PLT 21–50 x103/µL) had flags indicating unreliable values using this function which prevented any further comparison.
| PLT threshold (103/µL) | Sensitivity (%) | Specificity (%) | Agreement (%) |
cobas m 511 vs. | 10 | 95.5 | 96.8 | 96.5 |
20 | 93.6 | 94.1 | 93.9 | |
50 | 98.6 | 97.6 | 98.3 | |
Sysmex Analyzer (PLT-F) | 10 | 100.0 | 96.7 | 97.3 |
20 | 100.0 | 92.5 | 95.6 | |
50 | 100.0 | 97.6 | 99.1 | |
cobas m 511 vs.
| 10 | 88.0 | 97.7 | 95.6 |
20 | 94.1 | 100.0 | 97.3 | |
50 | 100.0 | 100.0 | 100.0 |
Conclusion
These data demonstrate the robustness and accuracy of platelet counts reported by the cobas m 511 system. Many samples were flagged using the Sysmex PLT-I function that, in routine use, would have reflexed to the PLT-F function. All samples on the cobas m 511 system had valid PLT results.
Session topic: 33. Platelets disorders
Keyword(s): Platelet
Abstract: PB2352
Type: Publication Only
Background
The cobas m 511 integrated hematology analyzer is a novel slide-based system that performs a CBC, WBC differential, reticulocyte count, and nucleated RBC count using digital analysis of a microscope slide.
Aims
To assess the accuracy of low platelet (PLT) counts on the cobas m 511 compared with the Sysmex® XN-10 Automated Hematology Analyzer and BD FACSCanto™ Flow Cytometer in a single-center study.
Methods
Residual whole blood samples (n=115) in the PLT range 1-505 x103/µL (based on flow cytometery using CD61, CD41a, and CD42b antibodies) were randomly processed on each system. Sysmex samples were set to automatically reflex to PLT-F function, which is marketed as more reliable for thrombocytic or problematic samples than the standard impedance PLT-I function. Three analyses were performed: cobas m 511 and Sysmex Analyzer versus flow cytometer (reference), and cobas m 511 versus Sysmex Analyzer (reference). Data were compared using three thresholds and results included if a valid PLT result was obtained on both systems.
Results
All low PLT samples had valid results with the cobas m 511 and flow cytometry. Two (1.7%) samples were flagged with the Sysmex Analyzer (PLT-F) indicating unreliable results. The cobas m 511 demonstrated excellent accuracy compared with flow cytometry, with ≥93.6% sensitivity, specificity, and agreement, and good accuracy compared with Sysmex Analyzer (Table 1). Attempts were made to also study results for the Sysmex Analyzer PLT-I function; however, the vast majority of samples (100% for PLT counts ≤10, 80% for PLT 11–20, and 28% for PLT 21–50 x103/µL) had flags indicating unreliable values using this function which prevented any further comparison.
| PLT threshold (103/µL) | Sensitivity (%) | Specificity (%) | Agreement (%) |
cobas m 511 vs. | 10 | 95.5 | 96.8 | 96.5 |
20 | 93.6 | 94.1 | 93.9 | |
50 | 98.6 | 97.6 | 98.3 | |
Sysmex Analyzer (PLT-F) | 10 | 100.0 | 96.7 | 97.3 |
20 | 100.0 | 92.5 | 95.6 | |
50 | 100.0 | 97.6 | 99.1 | |
cobas m 511 vs.
| 10 | 88.0 | 97.7 | 95.6 |
20 | 94.1 | 100.0 | 97.3 | |
50 | 100.0 | 100.0 | 100.0 |
Conclusion
These data demonstrate the robustness and accuracy of platelet counts reported by the cobas m 511 system. Many samples were flagged using the Sysmex PLT-I function that, in routine use, would have reflexed to the PLT-F function. All samples on the cobas m 511 system had valid PLT results.
Session topic: 33. Platelets disorders
Keyword(s): Platelet