Table 4.
QC outliers on the glucose meters with Sigma values less than 4 in the QC chart review.
| Sigma value | QC level | Number of QC chart | Chart without outlier (%) | Outlier between ±3SD and 4SD (%) | Outlier above or below ±4SD(%) | Average of meter SD/all-meter SD | Average of meter bias/all-meter SD |
|---|---|---|---|---|---|---|---|
| ∼<3 | Low | 4 | 25 | 25 | 75 | 1.81 | 0.39 |
| High | 12 | 27 | 20 | 80 | 1.95 | 0.68 | |
| ∼<3.5 | Low | 16 | 31 | 67 | 33 | 1.56 | 0.45 |
| High | 25 | 22 | 30 | 70 | 1.42 | 0.39 | |
| ∼<4 | Low | 37 | 57 | 68 | 32 | 1.37 | 0.38 |
| High | 78 | 62 | 83 | 17 | 1.21 | 0.45 |
Absolute bias was used in the calculation of average meter bias/all-meter SD to eliminate the effect of the direction of bias. QC; quality control. SD; standard deviation.
A.