Mean prothrombin times (seconds) and interlaboratory variation (CV) in two separate external quality assessment surveys
| Sample A not illuminated | Sample B not illuminated | Sample C illuminated | |||||
|---|---|---|---|---|---|---|---|
| Reagent | n | Mean | CV (%) | Mean | CV (%) | Mean | CV (%) |
| The artificial blood samples were prepared separately for each survey. Artificial blood sample A was prepared from pooled coumarin plasma without addition of methylene blue and without illumination. Blood sample B was prepared from the same pooled coumarin plasma but with addition of methylene blue and without illumination. Blood sample C was prepared from the same pooled coumarin plasma but with the addition of methylene blue and with illumination. | |||||||
| n, number of laboratories. | |||||||
| Thrombotest | 40 | 117.5 | 5.4 | 117.6 | 5.4 | 118.2 | 5.3 |
| Thrombotest | 40 | 108.1 | 5.6 | 109.1 | 5.9 | 110.6 | 6.1 |
| Recombiplastin | 18 | 39.8 | 6.2 | 39.3 | 6.0 | 42.1 | 5.8 |
| Recombiplastin | 19 | 37.7 | 5.7 | 38.2 | 4.4 | 41.6 | 5.3 |
| PT-Fib HS | 17 | 30.7 | 7.0 | 31.0 | 7.2 | 33.7 | 8.3 |
| PT-Fib HS | 18 | 29.8 | 7.4 | 30.2 | 6.2 | 33.6 | 6.8 |
| Thromborel-S | 13 | 38.3 | 6.1 | 38.1 | 6.3 | 40.1 | 7.1 |
| Thromborel-S | 12 | 36.8 | 6.7 | 37.5 | 7.2 | 39.9 | 7.8 |
| Hepato Quick | 15 | 85.1 | 4.1 | 84.7 | 3.9 | 91.5 | 4.2 |
| Hepato Quick | 16 | 85.7 | 3.6 | 87.0 | 3.6 | 92.4 | 3.3 |