Sigma Metric Analysis
ADVIA 2120i in Croatia, 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 ADVIA 2120i instrument.
ADVIA 2120i in Croatia, multimode analysis
January 2023
Sten Westgard, MS
See the other analyses in this series:
- Beckman Coulter DxC 700
- Abbott Alinity
- Siemens Atellica
- Siemens Atellica in Romania
- Siemens Atellica in Spain
- Siemens ADVIA 2120i
- Roche c501 in Turkey
- Roche c501 in Saudi Arabia
- MicroLab RX-50 in India
- Roche cobas 6000 immunoassays in Turkey
- Sysmex XN 350 in India
- Mindray 7500 in China
- Mindray BS 2000M in China
This Siemens ADVIA 2120i comes from University Hospital "Sveti Duh" in Zagreb, Croatia:
Verification of a 6-part haematology analyser Siemens ADVIA 2120i, Helena Cicak, Vanja Radisic Biljak, Ana-Maria Simundic, Biochem Med (Zagreb) 2022:32;020710
"For estimation of precision and bias, three levels of the commercial ADVIA 3 in 1 TESTpoint Haematology Controls (Siemens, Erlangen, Germany) were used...."
The use of manufacturer controls are a weakness of this study, as they are less likely to provide an honest, independent assessment of the performance of the instrument. But we'll go ahead and use them, because, as you will see, even the most optimistic controls don't provide a rosy picture.
There are three levels that will be analyzed here. So for 6 parameters there will be 18 data points to plot on the Normalized Method Decision Chart. Note that while the EFLM biological variation database contains performance specifications for MCV, the CLIA 2024 goals do not. Thus, the graphs for CLIA will only cover 5 parameters and 15 data points.
ADVIA 2120i in Croatia |
||
TEST | % Bias | %CV |
Hemoglobin | 2.100 | 1.70 |
1.000 | 1.30 | |
1.700 | 0.40 | |
Hematocrit | 0.800 | 1.20 |
1.800 | 1.30 | |
1.800 | 1.20 | |
MCV | 0.900 | 0.70 |
1.400 | 0.80 | |
2.200 | 0.60 | |
Platelets | 4.900 | 4.40 |
2.700 | 2.50 | |
4.500 | 2.20 | |
RBC | 1.700 | 0.80 |
0.500 | 0.80 | |
0.400 | 1.00 | |
WBC | 1.100 | 2.30 |
1.500 | 2.40 | |
1.400 | 2.50 |
The TEa goals applied can be found on our Consolidated Hematology Performance Specifications page.
Sigma-metrics according to EFLM-derived DESIRABLE performance specifications
The EFLM desirable specifications used to be the de facto global standard, but have fallen out of favor due to their toughness.
The ADVIA 2120 has two-thirds of the performance below 3 Sigma, and more than one-third below 2 Sigma.
Not surprising then, that EFLM recommended lowering the standards.
Sigma-metrics according to EuBIVAS-derived MINIMUM performance specifications
There is a huge improvement, almost one-third of performance now in the Six Sigma zone, and less than one-third of that performance below 3 Sigma.
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
The CLIA 2024 goals are not easy on the ADVIA 2120i. Similar to the desirable EFLM goals, two-thirds of the performance is below 3 Sigma. And no point is 6 Sigma.
Conclusion
Even with possibly the most favorable assessment (from their own controls), the ADVIA 2120i has a lot of difficulty hitting the desirable EFLM goals and the CLIA 2024 goals. While EFLM minimum specifications are going to make it easier on the hematology laboratory, CLIA 2024 is going to be the hardest set of goals for future laboratories.
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?
ADVIA 2120i in Croatia |
Expanded | EFLM | Panteghini | ||
TEST | %CV | MU | Min MAU | Preferred pU | Notes |
Hemoglobin | 1.70 | 3.4 | 4.1 | 2.8 (des) 4.2 (min) |
Passes both |
1.30 | 2.6 | 4.1 | 2.8 (des) 4.2 (min) |
Passes both | |
0.40 | 0.8 | 4.1 | 2.8 (des) 4.2 (min) |
Passes both | |
Hematocrit | 1.20 | 2.4 | 4.2 | -- | Passes MAU |
1.30 | 2.6 | 4.2 | -- | Passes MAU | |
1.20 | 2.4 | 4.2 | -- | Passes MAU | |
MCV | 0.70 | 1.4 | 1.2 | -- | Fails MAU |
0.80 | 1.6 | 1.2 | -- | Fails MAU | |
0.60 | 1.2 | 1.2 | -- | Passes MAU | |
Platelets | 4.40 | 8.8 | -- | 4.85 (des) 7.28 (min) |
Fail both pU's |
2.50 | 5.0 | -- | 4.85 (des) 7.28 (min) |
Passes min pU | |
2.20 | 4.4 | -- | 4.85 (des) 7.28 (min) |
Passes des pU | |
RBC | 0.80 | 1.6 | 3.9 | 1.55 (des) 2.33 (min) |
Passes min pU, MAU |
0.80 | 1.6 | 3.9 | 1.55 (des) 2.33 (min) |
Passes min pU, MAU | |
1.00 | 2.0 | 3.9 | 1.55 (des) 2.33 (min) |
Passes min pU, MAU | |
WBC | 2.30 | 4.6 | 16.2 | 5.65% (des) 8.48% (min) |
Passes both |
2.40 | 4.8 | 16.2 | 5.65% (des) 8.48% (min) |
Passes both | |
2.50 | 5.0 | 16.2 | 5.65% (des) 8.48% (min) |
Passes both |
If we judge these assays by the various mu 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. MAU and pU are definitely more forgiving than the use of TEa to set performance specifications for hematology.