Sigma Metric Analysis
A sysmex XN-330 in India
A study looked at the Sigma metric performance of a Sysmex XN 330 in India. If this laboratory was in the US, would they be able to meet CLIA 2025 targets?
Hematology on the Sysmex XN 330 in India
December 2025
Sten Westgard, MS
A recent study from the Trichy SRM Medical College Hospital and Research Centre evaluated the performance of a Sysmex XN 330.
Analysis of hematology quality control using Six Sigma Metrics, Krishnasamy S, Banu Iqbal FJ, Genesamoorthy VK, Rathinam S, Banthavi SP. International Journal o fPharmaceutical Quality Assurance 2025; 16(8);112-117.
Calculating Sigma metrics from routine laboratory performance data.
QC samples were collected for 6 months with three levels. CLIA 1992 goals were used, and Sigma metric calculations were calculated monthly. In this analysis we're going to change up these two things. We're going to merge all 6 months together and take averages of the imprecision and bias over that time. And then we will apply the latest CLIA 2025 goals. Bias is calculated against a target mean, and we also averaged that absolute bias over 6 months.
| TEST | TEa Source | TEa | Bias 10/24 | Bias 11/24 | Bias 12/24 | Bias 1/25 | Bias 2/25 | Bias 3/25 | Avg % Bias | CV 10/24 | CV 11/24 | CV 12/24 | CV 1/25 | CV 2/25 | CV 3/25 | Avg CV |
| Hemoglobin | CLIA 2025 | 4 | 1.8 | 1.7 | 1.7 | 1.70 | 1.60 | 1.60 | 1.7 | 1.0 | 0.7 | 1.1 | 1.4 | 1.1 | 1.2 | 1.1 |
| Hemoglobin | 4% | 4 | 0.8 | 0.7 | 0.7 | 0.70 | 0.70 | 0.70 | 0.7 | 0.7 | 0.5 | 0.6 | 0.5 | 0.8 | 0.7 | 0.9 |
| Hemoglobin | 4% | 4 | 0 | 0 | 0 | 0.00 | 0.50 | 0.00 | 0.1 | 0.5 | 0.5 | 0.5 | 0.7 | 0.5 | 0.9 | 0.6 |
| Hematocrit | CLIA 2025 | 4 | 0.6 | 2.9 | 2.3 | 1.70 | 4.50 | 2.80 | 2.5 | 1.5 | 1.6 | 1.2 | 1.4 | 1.2 | 1.3 | 1.0 |
| Hematocrit | 4% | 4 | 0 | 1 | 0.2 | 0.00 | 2.90 | 1.00 | 0.9 | 1.2 | 1.3 | 0.9 | 0.8 | 1.4 | 1.0 | 1.2 |
| Hematocrit | 4% | 4 | 1.2 | 0.8 | 1.7 | 2.00 | 1.70 | 0.20 | 1.3 | 1.4 | 1.3 | 1.0 | 1.0 | 1.2 | 1.2 | 1.1 |
| Platelets | CLIA 2025 | 25 | 11.1 | 6.8 | 12 | 3.30 | 1.70 | 1.70 | 6.1 | 12.1 | 12.4 | 16.4 | 13.7 | 8.4 | 10.4 | 6.7 |
| Platelets | 25% | 25 | 2.2 | 0 | 2.8 | 2.30 | 1.90 | 1.40 | 1.8 | 4.0 | 4.3 | 6.5 | 5.2 | 3.7 | 5.9 | 8.6 |
| Platelets | 25% | 25 | 2.8 | 0.5 | 0.1 | 0.00 | 1.50 | 0.90 | 1.0 | 2.2 | 22.2 | 2.6 | 1.8 | 1.8 | 3.0 | 5.3 |
| RBC | CLIA 2025 | 4 | 0.8 | 1.7 | 0 | 0.80 | 2.10 | 1.2 | 1.1 | 0.9 | 1.2 | 1.1 | 1.3 | 1.0 | 1.1 | 3.4 |
| RBC | CLIA 2025 | 4 | 0.08 | 0.4 | 0.4 | 0.20 | 1.10 | 0.4 | 0.4 | 0.8 | 0.9 | 0.7 | 0.6 | 1.1 | 0.9 | 1.0 |
| RBC | 4% | 4 | 0.5 | 0.5 | 1.5 | 1.10 | 0.10 | 0.5 | 0.7 | 0.7 | 0.9 | 0.8 | 0.8 | 1.0 | 0.9 | 0.8 |
| WBC | CLIA 2025 | 10 | 1.6 | 0.8 | 0.4 | 0.80 | 0.80 | 0.0 | 0.7 | 2.6 | 2.6 | 2.7 | 2.7 | 2.8 | 3.2 | 1.8 |
| WBC | CLIA 2025 | 10 | 0.9 | 0.2 | 0.8 | 0.20 | 0.90 | 0.4 | 0.6 | 1.5 | 1.5 | 1.5 | 1.8 | 1.9 | 2.5 | 2.3 |
| WBC | 10% | 10 | 0.1 | 0.3 | 0.1 | 0.30 | 0.10 | 0.8 | 0.3 | 1.1 | 1.1 | 1.4 | 1.5 | 1.4 | 1.9 | 1.6 |
Here are the resulting calculations:
| Test | Sigma |
| Hemoglobin | 2.1 |
| Hemoglobin | 3.8 |
| Hemoglobin | 6.4 |
| Hematocrit | 1.6 |
| Hematocrit | 2.6 |
| Hematocrit | 2.4 |
| Platelets | 2.8 |
| Platelets | 2.7 |
| Platelets | 4.6 |
| RBC | 0.9 |
| RBC | 3.7 |
| RBC | 3.9 |
| WBC | 5.1 |
| WBC | 4.1 |
| WBC | 6.1 |
Graphic Display of performance by Normalized Method Decision Chart (NMEDx)
Only a third of this performance is 4, 5, or 6 Sigma performance. The rest is fairly low in performance, and would require all the Westgard Rules and more.
Conclusion
The hematology goals for CLIA 2025 are significantly harder to hit, no matter where in the world you are. While this lab is located in India, and thus is not subject to the CLIA regulations, this kind of performance would be noteworthy in the US, and not for a good reason.