Tools, Technologies and Training for Healthcare Laboratories

Mindray BC 7500 in China, multimode analysis

Continuing in our analysis of hematology systems, we look at the impact of new CLIA and EFLM goals on the assessment of the Mindray BC 7500 instrument.

Mindray BC 7500 in China, multimode analysis

January 2023
Sten Westgard, MS

See the other analyses in this series:

This Mindray BC-7500 data comes from Fujian Medical University Union Hospital, in Fuzhou, China:

Performance evaluation of routine blood and C-reactive protein analysis using Mindray BC-7500 auto hematology analyzer. Zhen Lin, Qiu Lin, Pingli Yu, Zhixin Chen, Haifeng Lin, Bin Zhu, Meihua Wang, Yingping Cao. Ann Transl Med 2022;10(10):588.

The study was conducted with IQC data from June 2021 to September 2021.

"[R]outine  blood parameters werre evaluated with BC-6D and BC-RET for 31 days...The with-run[sic] between-run, between-day, and within-laboratory precision results of each parameter were calculated using Analyse-it software...."

"[C]omparability assessment of the BC-7500 CRP analyzer was performed in three parts, with a total of 1,584 fresh whole blood samples...collected for comparison of routine blood parameters..with the Sysmex-XN."

There are three levels that will be analyzed here. So for 5 parameters there will be 15 data points to plot on the Normalized Method Decision Chart. Note that while the EFLM biological variation database contains performance specifications for differentials, the CLIA 2024 goals do not. Thus, the graphs for CLIA will contain a significantly lower number of data points.

Mindray BC 7500 China with CLIA 2024    
TEST % Bias CV
Hemoglobin 0.57 0.85
  0.76 0.73
  1.77 1.06
Hematocrit 0.16 1.11
  0.07 1.02
  1.21 1.43
MCV 1.69 0.72
  1.27 0.79
  0.64 1.15
Platelets -Impedance 0.84 1.95
  0.58 2.71
  0.75 7.06
Platelets - Optical 0.8 1.95
  0.72 2.71
  0.21 7.06
RBC 0.04 1.18
  0.070 0.97
  0.74 1.08
WBC 0.21 1.18
  0.07 1.71
  0.15 2.51
Lymphocytes 3.74 2.49
  3.25 2.29
  4.51 3.55
Monocytes 11.9 4.72
  12.50 7.18
  23.72 14.02
Eosinophils 2.39 3.83
  2.36 6.09
  1.96 7.44
Basophils 33.30 15.44
  33.30 26.15
  33.30 41.88
Neutrophils 3.23 1.04
  3.43 1.46
  3.14 2.15

The TEa goals applied can be found on our Consolidated Hematology Performance Specifications page.

Sigma-metrics according to EFLM-derived DESIRABLE performance specifications

2023 mindray bc 7500 eflm des NMEDX

The EFLM desirable specifications used to be the de facto global standard, but have fallen out of favor due to their toughness.

The BC-7500 has about 7 points in the Bull's-Eye, but 14 points in the poor and unacceptable zones.

Not surprising then, that EFLM recommended lowering the standards.

Sigma-metrics according to EuBIVAS-derived MINIMUM performance specifications

 2023 mindray bc 7500 eflm min NMEDX
There is a huge improvement, almost doubling the number of Six Sigma assay performance, but there is still a significant number of unacceptable points.

Here's one of the most interesting new aspects of CLIA's new 2024 goals. Are they more or less demanding than EFLM goals?

Sigma-metrics according to CLIA 2024 performance specifications

 2023 mindray bc 7500 CLIA 2024

 It's very difficult to make an apples-to-apples comparison with CLIA 2024 and the EFLM goals, because, of course, the EFLM goals cover all the differentials and the CLIA 2024 does not. So a significant number of parameters drop out. But those that remain do not get the generous grade that the EFLM minimum goals provided.

Astonishingly, the CLIA 2024 for hematology are far more demanding than EFLM. There's only 1 6-Sigma data point, the center of gravity of performance is in the 3-4 Sigma zone.

Conclusion

All three sets of goals are not that kind to the BC 7500. If the three dominant benchmarks deliver an unacceptable verdict of an emerging leader of hematology instruments, what are we to conclude? Are the instruments fundamentally flawed, or the goals themselves?

Bonus Analysis: How are these assays judged when MU is compared to MAU, pU specifications?

While the original publication didn't intend to assess uncertainty, since imprecision was measured, the simple estimation of uncertainty can be made. So let's take a good look at that. Perhaps the specifications for hematology MU are more forgiving?

Mindray BC 7500 China with CLIA 2024   Expanded EFLM Panteghini  Final
TEST CV MU Min MAU Preferred pU Notes
Hemoglobin 0.85 1.7  4.1 2.8 (des)
4.2 (min)
passes both
  0.73 1.46  4.1 2.8 (des)
4.2 (min)
passes both
  1.06 2.06  4.1 2.8 (des)
4.2 (min)
passes both
Hematocrit 1.11  2.22  4.2  -- passes MAU
  1.02  2.04  4.2  -- passes MAU 
  1.43  2.86  4.2  -- passes MAU 
MCV 0.72  1.44  1.2  --  fails MAU
  0.79  1.58  1.2  --  fails MAU
  1.15  2.3  1.2  --  fails MAU
Platelets -Impedance 1.95  3.9  --  4.85 (des)
7.28 (min)
 fails pU
  2.71  5.42  -- 4.85 (des)
7.28 (min)
 fails pU
  7.06  14.12  -- 4.85 (des)
7.28 (min)
 fails pU
Platelets - Optical 1.95  3.9  -- 4.85 (des)
7.28 (min)
 fails pU
  2.71  5.42  -- 4.85 (des)
7.28 (min) 
 fails pU
  7.06  14.12  --  4.85 (des)
7.28 (min)
 fails pU
RBC 1.18  2.36   3.9 1.55 (des)
2.33 (min)  
passes MAU,
fails pU
  0.97  1.94   3.9 1.55 (des)
2.33 (min) 
passes MAU,
fails des pU 
  1.08  2.16  3.9 1.55 (des)
2.33 (min) 
passes MAU,
fails des pU
WBC 1.18 2.36   16.2 5.65% (des)
8.48% (min)
 passes both
  1.71  3.42   16.2 5.65% (des)
8.48% (min) 
 passes both
  2.51  5.02   16.2 5.65% (des)
8.48% (min) 
 passes both
Lymphocytes 2.49  4.98  16.2  -- passes MAU
  2.29  4.58  16.2  -- passes MAU 
  3.55  7.1  16.2  -- passes MAU 
Monocytes 4.72  9.42  20  -- passes MAU  
  7.18  14.36  20  -- passes MAU  
  14.02  28.02  20  -- passes MAU  
Eosinophils 3.83  7.66  22.5 -- passes MAU   
  6.09  12.18  22.5 -- passes MAU   
  7.44  14.88  22.5 -- passes MAU   
Basophils 15.44  30.88  18.6 -- fails MAU
  26.15  52.3  18.6 -- fails MAU 
  41.88  83.98  18.6 -- fails MAU 
Neutrophils 1.04 2.08  21 -- passes MAU
  1.46 2.92  21 -- passes MAU 
  2.15  4.3  12 -- passes MAU 

If we judge these assays by the various performance specifications set forth by EFLM and Panteghini et al, there are far more victories than when these parameters are judged by the TEa benchmarks. Although, there is some real discrepancy between what pU and MAU believe are acceptable. MAU and pU are definitely  more forgiving than the use of TEa to set performance specifications.