Results of proficiency testing for therapeutic drug monitoring of general subgroup test substances during 2019
| Test substances | Method | 19-01 | 19-02 | 19-03 | 19-04 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. of labs | Mean±SD | CV (%) | No. of labs | Mean±SD | CV (%) | No. of labs | Mean±SD | CV (%) | No. of labs | Mean±SD | CV (%) | ||
| Acetaminophen | All methods | 6 | 8.84±0.67 | 7.57 | 6 | 31.98±0.53 | 1.66 | 6 | 36.54±0.80 | 2.20 | 6 | 10.68±0.56 | 5.21 |
| Cobas c311/c501/c502/c702 | 4 | 8.18±1.33 | 16.21 | 4 | 31.93±2.19 | 6.87 | 4 | 36.75±0.75 | 2.05 | 4 | 10.65±0.61 | 5.76 | |
| Cobas Integra | 2 | 9.00±0.42 | 4.71 | 2 | 32.15±0.64 | 1.98 | 2 | 37.75±2.90 | 7.68 | 2 | 10.75±0.64 | 5.92 | |
| Amikacin | All methods | 6 | 4.40±0.25 | 5.79 | 6 | 14.32±0.83 | 5.77 | 6 | 15.05±0.43 | 2.84 | 6 | 4.52±0.35 | 7.85 |
| Cobas c311/c501/c502/c702 | 4 | 4.27±0.15 | 3.58 | 4 | 14.25±0.72 | 5.04 | 4 | 15.08±0.49 | 3.27 | 4 | 4.33±0.06 | 1.33 | |
| Carbamazepine | All methods | 39 | 2.81±0.24 | 8.65 | 39 | 8.19±0.40 | 4.87 | 38 | 8.00±0.24 | 3.05 | 38 | 2.83±0.18 | 6.44 |
| Architect i | 17 | 2.94±0.19 | 6.37 | 17 | 8.37±0.32 | 3.77 | 15 | 8.13±0.13 | 1.60 | 15 | 2.93±0.09 | 3.12 | |
| Cobas c311/c501/c502/c702 | 11 | 2.68±0.09 | 3.43 | 11 | 7.86±0.14 | 1.73 | 14 | 7.81±0.26 | 3.33 | 14 | 2.69±0.15 | 5.56 | |
| Cobas Integra | 5 | 2.58±0.08 | 3.24 | 5 | 8.16±0.32 | 3.93 | 3 | 8.07±0.06 | 0.72 | 3 | 2.67±0.06 | 2.17 | |
| ADVIA Centaur | 2 | 3.25±0.21 | 6.53 | 2 | 9.10±0.28 | 3.11 | 2 | 7.95±0.49 | 6.23 | 2 | 3.00±0.14 | 4.71 | |
| Digoxin | All methods | 60 | 0.57±0.10 | 17.79 | 60 | 1.58±0.14 | 9.13 | 59 | 1.57±0.19 | 11.88 | 59 | 0.59±0.13 | 21.67 |
| Architect i | 32 | 0.50±0.00 | 0.00 | 32 | 1.50±0.00 | 0.00 | 31 | 1.40±0.00 | 0.00 | 31 | 0.50±0.00 | 0.00 | |
| Cobas c311/c501/c502/c702 | 9 | 0.66±0.10 | 15.46 | 9 | 1.70±0.00 | 0.00 | 11 | 1.72±0.08 | 4.37 | 11 | 0.74±0.07 | 9.16 | |
| Cobas e411/e601/e602/e801 | 8 | 0.60±0.00 | 0.00 | 8 | 1.59±0.07 | 4.35 | 8 | 1.67±0.05 | 3.10 | 8 | 0.64±0.08 | 12.24 | |
| ADVIA Centaur | 4 | 0.80±0.00 | 0.00 | 4 | 1.87±0.06 | 3.09 | 4 | 1.88±0.10 | 5.11 | 4 | 0.75±0.06 | 7.70 | |
| Cobas Integra | 4 | 0.68±0.17 | 25.30 | 4 | 1.70±0.16 | 9.61 | 2 | 1.90±0.00 | 0.00 | 2 | 0.95±0.07 | 7.44 | |
| Gentamicin | All methods | 5 | 2.90±0.32 | 10.90 | 5 | 5.13±0.12 | 2.25 | 5 | 5.68±0.17 | 3.01 | 5 | 3.00±0.12 | 3.85 |
| Architect i | 3 | 2.97±0.15 | 5.15 | 3 | 5.37±0.29 | 5.38 | 3 | 5.70±0.20 | 3.51 | 3 | 2.97±0.12 | 3.89 | |
| Cobas Integra | 2 | 2.80±0.57 | 20.20 | 2 | 4.65±0.49 | 10.64 | 2 | 5.05±0.78 | 15.40 | 2 | 2.75±0.49 | 18.00 | |
| Lithium | All methods | 35 | 0.51±0.02 | 4.76 | 35 | 1.31±0.12 | 9.29 | 33 | 1.38±0.16 | 11.82 | 33 | 0.51±0.05 | 9.42 |
| NOVA 4 | 5 | 0.51±0.03 | 4.98 | 5 | 1.43±0.10 | 7.21 | 6 | 1.51±0.11 | 7.49 | 6 | 0.51±0.04 | 7.21 | |
| AVL9180 | 6 | 0.53±0.01 | 1.89 | 6 | 1.41±0.05 | 3.71 | 6 | 1.48±0.10 | 6.99 | 6 | 0.55±0.01 | 0.91 | |
| Cobas c311/c501/c502/c702 | 5 | 0.51±0.01 | 1.14 | 5 | 1.25±0.01 | 0.46 | 5 | 1.34±0.11 | 8.02 | 5 | 0.52±0.04 | 7.94 | |
| Olympus AU | 5 | 0.50±0.03 | 5.20 | 5 | 1.24±0.04 | 2.87 | 4 | 1.23±0.01 | 1.05 | 4 | 0.48±0.01 | 1.22 | |
| Roche 9100 Series | 3 | 0.54±0.02 | 3.88 | 3 | 1.39±0.01 | 0.42 | 3 | 1.46±0.09 | 5.89 | 3 | 0.56±0.07 | 12.08 | |
| Others | 4 | 0.48±0.02 | 3.16 | 4 | 1.15±0.02 | 1.80 | 3 | 1.43±0.24 | 16.44 | 3 | 0.57±0.12 | 20.45 | |
| Methotrexate | All methods | 19 | 0.41±0.01 | 1.78 | 19 | 1.14±0.05 | 4.22 | 18 | 1.20±0.06 | 5.02 | 18 | 0.43±0.02 | 3.94 |
| Architect i | 14 | 0.41±0.00 | 0.00 | 14 | 1.15±0.03 | 2.70 | 13 | 1.20±0.06 | 5.37 | 13 | 0.43±0.02 | 3.55 | |
| Cobas c311/c501/c502/c702 | 3 | 0.41±0.02 | 5.12 | 3 | 1.16±0.11 | 9.72 | 3 | 1.25±0.14 | 11.00 | 3 | 0.44±0.05 | 11.13 | |
| Toshiba | 2 | 0.39±0.02 | 5.51 | 2 | 1.10±0.01 | 1.29 | 2 | 1.23±0.02 | 1.72 | 2 | 0.46±0.01 | 1.55 | |
| Phenobarbital | All methods | 24 | 9.40±0.43 | 4.58 | 24 | 23.89±0.95 | 3.96 | 22 | 23.65±0.61 | 2.59 | 22 | 9.61±0.35 | 3.60 |
| Architect i | 11 | 9.56±0.29 | 3.01 | 11 | 24.35±0.65 | 2.68 | 10 | 24.01±0.44 | 1.83 | 10 | 9.79±0.19 | 1.94 | |
| Cobas c311/c501/c502/c702 | 6 | 8.98±0.64 | 7.09 | 6 | 23.67±1.13 | 4.78 | 7 | 23.70±0.48 | 2.01 | 7 | 9.57±0.38 | 3.99 | |
| Cobas Integra | 4 | 9.10±0.53 | 5.81 | 4 | 22.80±0.36 | 1.56 | 3 | 23.00±0.26 | 1.15 | 3 | 9.40±0.10 | 1.06 | |
| ADVIA Centaur | 2 | 12.05±0.92 | 7.63 | 2 | 30.05±0.35 | 1.18 | 2 | 27.95±1.06 | 3.79 | 2 | 12.10±0.99 | 8.18 | |
| Phenytoin | All methods | 38 | 6.10±0.29 | 4.79 | 38 | 12.83±0.45 | 3.48 | 37 | 12.60±0.29 | 2.27 | 37 | 6.38±0.17 | 2.64 |
| Architect i | 21 | 6.22±0.24 | 3.79 | 21 | 12.95±0.47 | 3.67 | 19 | 12.55±0.40 | 3.15 | 19 | 6.43±0.15 | 2.31 | |
| Cobas c311/c501/c502/c702 | 9 | 5.76±0.29 | 5.07 | 9 | 12.86±0.17 | 1.34 | 10 | 12.58±0.13 | 1.03 | 10 | 6.37±0.15 | 2.35 | |
| Cobas Integra | 4 | 5.80±0.12 | 1.99 | 4 | 12.40±0.18 | 1.47 | 3 | 12.57±0.29 | 2.30 | 3 | 6.20±0.10 | 1.61 | |
| ADVIA Centaur | 2 | 6.50±0.42 | 6.53 | 2 | 14.40±0.28 | 1.96 | 2 | 15.90±1.41 | 8.89 | 2 | 8.20±0.71 | 8.62 | |
| Phenytoin, free | All methods (Dimension) | 1 | - | - | 1 | - | - | 1 | - | - | 1 | - | - |
| Salicylate | All methods | 3 | 3.60±2.72 | 75.58 | 3 | 11.08±8.31 | 74.98 | 3 | 10.95±8.12 | 74.20 | 3 | 3.66±2.73 | 74.56 |
| Cobas c311/c501/c502/c702 | 2 | 5.17±0.33 | 6.43 | 2 | 15.88±0.32 | 2.00 | 2 | 15.64±0.21 | 1.36 | 2 | 5.23±0.11 | 2.03 | |
| Theophylline | All methods | 27 | 5.31±0.15 | 2.81 | 27 | 14.16±0.29 | 2.08 | 24 | 13.59±0.52 | 3.80 | 24 | 5.27±0.21 | 3.94 |
| Architect i | 14 | 5.23±0.07 | 1.29 | 14 | 14.15±0.25 | 1.77 | 12 | 13.29±0.35 | 2.63 | 12 | 5.15±0.05 | 1.01 | |
| Cobas c311/c501/c502/c702 | 7 | 5.28±0.08 | 1.58 | 7 | 14.00±0.32 | 2.30 | 8 | 13.70±0.36 | 2.62 | 8 | 5.40±0.21 | 3.96 | |
| Cobas Integra | 4 | 5.50±0.29 | 5.35 | 4 | 14.50±0.10 | 0.69 | 3 | 14.53±0.12 | 0.79 | 3 | 5.50±0.00 | 0.00 | |
| ADVIA Centaur | 2 | 6.15±0.07 | 1.15 | 2 | 16.15±0.35 | 2.19 | 1 | - | - | 1 | - | - | |
| Tobramycin | All methods | 3 | 1.07±0.25 | 23.59 | 3 | 3.33±0.31 | 9.17 | 3 | 3.37±0.35 | 10.43 | 3 | 1.03±0.25 | 24.35 |
| Cobas c311/c501/c502/c702 | 2 | 1.20±0.14 | 11.79 | 2 | 3.50±0.14 | 4.04 | 2 | 3.55±0.21 | 5.98 | 2 | 1.15±0.21 | 18.45 | |
| Test substances | Method | 19-01 | 19-02 | 19-03 | 19-04 | ||||||||
| No. of labs | Mean±SD | CV (%) | No. of labs | Mean±SD | CV (%) | No. of labs | Mean±SD | CV (%) | No. of labs | Mean±SD | CV (%) | ||
| Valproic acid | All methods | 84 | 30.55±1.47 | 4.82 | 84 | 72.22±2.72 | 3.77 | 84 | 78.72±3.70 | 4.70 | 84 | 31.00±1.88 | 6.05 |
| Architect i | 43 | 30.36±1.03 | 3.40 | 43 | 71.42±2.15 | 3.01 | 42 | 77.58±3.43 | 4.42 | 42 | 30.24±1.36 | 4.50 | |
| Cobas c311/c501/c502/c702 | 18 | 31.25±1.45 | 4.65 | 18 | 72.64±1.57 | 2.16 | 21 | 79.56±4.29 | 5.39 | 21 | 31.82±1.25 | 3.93 | |
| ADVIA Centaur | 5 | 32.60±0.28 | 0.87 | 5 | 73.38±2.95 | 4.02 | 5 | 84.00±7.18 | 8.54 | 5 | 33.58±1.45 | 4.31 | |
| Dimension | 3 | 31.63±1.50 | 4.75 | 3 | 73.27±1.62 | 2.21 | 4 | 79.58±2.90 | 3.64 | 4 | 32.95±0.50 | 1.52 | |
| Cobas Integra | 6 | 29.20±0.29 | 1.00 | 6 | 71.05±0.36 | 0.50 | 4 | 78.90±1.57 | 2.00 | 4 | 31.63±0.23 | 0.73 | |
| Others | 3 | 31.97±3.98 | 12.46 | 3 | 76.30±4.91 | 6.44 | 2 | 78.55±1.48 | 1.89 | 2 | 31.75±4.88 | 15.37 | |
| Valproic acid, free | All methods | 2 | 17.08±18.70 | 109.46 | 2 | 47.74±33.33 | 69.81 | 2 | 53.06±40.22 | 75.80 | 2 | 16.95±19.02 | 112.22 |
| Vancomycin | All methods | 70 | 13.75±0.91 | 6.58 | 70 | 36.99±2.61 | 7.07 | 74 | 38.05±2.75 | 7.22 | 74 | 14.01±0.54 | 3.85 |
| Architect i | 40 | 14.27±0.46 | 3.20 | 40 | 38.45±1.00 | 2.61 | 40 | 39.65±0.89 | 2.25 | 40 | 14.29±0.28 | 1.99 | |
| Cobas c311/c501/c502/c702 | 15 | 12.71±0.68 | 5.33 | 15 | 33.40±1.28 | 3.83 | 17 | 35.48±1.62 | 4.58 | 17 | 13.46±0.52 | 3.84 | |
| Dimension | 3 | 13.33±0.15 | 1.15 | 3 | 34.53±1.82 | 5.28 | 5 | 35.40±0.67 | 1.91 | 5 | 13.32±0.45 | 3.37 | |
| ADVIA Centaur | 3 | 10.33±0.75 | 7.26 | 3 | 28.27±1.00 | 3.54 | 3 | 31.63±0.80 | 2.54 | 3 | 11.57±0.12 | 1.00 | |
| Cobas Integra | 4 | 14.13±0.29 | 2.04 | 4 | 39.70±0.84 | 2.11 | 3 | 42.70±1.31 | 3.07 | 3 | 14.33±0.45 | 3.15 | |
| Olympus AU | 2 | 13.10±0.57 | 4.32 | 2 | 37.85±1.48 | 3.92 | 2 | 38.30±0.85 | 2.22 | 2 | 14.05±0.78 | 5.54 | |
The instruments were from the following companies: AVL9180, Cobas Integra, Cobas c modules, and 9100 Series analyzers (Roche Diagnostics, Mannheim, Germany), Architect i, Olympus AU, Nova 4, and Toshiba analyzers (Abbott Laboratories, Chicago, IL, USA), Beckman Coulter Inc. (Brea, CA, USA), Nova Biomedical Corp. (Waltham, MA, USA), Toshiba Medical Systems (Tokyo, Japan), and ADVIA Centaur, Atellica CH 930, Dimension, and Vista analyzers (Siemens Healthineers, Erlangen, Germany).
Abbreviations: SD, standard deviation; CV, coefficients of variation.