Table. 4.

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.

J Lab Med Qual Assur 2020;42:183~193 https://doi.org/10.15263/jlmqa.2020.42.4.183
© Lab Med Qual Assur