Table. 1.

Number of laboratories that participated in each therapeutic drug monitoring proficiency testing during 2015–2019

Test substances Year %Change (2019-2nd vs 2015-1st)

2015 2016 2017 2018 2019





1st 2nd 1st 2nd 1st 2nd 1st 2nd 1st 2nd
Acetaminophen 6 5 5 5 6 6 6 6 6 6 0.0
Amikacin 6 5 6 6 6 6 6 6 6 6 0.0
Carbamazepine 51 47 44 41 42 42 41 40 39 38 –25.5
Digoxin 73 70 67 66 70 69 65 62 60 59 –19.2
Gentamicin 5 5 5 5 5 5 5 4 5 5 0.0
Lithium 34 35 28 31 32 33 33 33 35 33 –2.9
Methotrexate 17 17 15 15 17 17 19 19 19 18 5.9
Phenobarbital 34 32 31 28 29 29 27 27 24 22 –35.3
Phenytoin 50 47 47 43 44 43 41 40 38 37 –26.0
Phenytoin, free 1 1 1 1 1 1 1 1 1 1 0.0
Salicylate 4 3 3 3 3 3 3 3 3 3 –25.0
Theophylline 43 41 36 36 35 32 29 28 27 24 –44.2
Tobramycin 3 3 3 3 3 3 3 3 3 3 0.0
Valproic acid 90 90 86 82 85 85 85 84 84 84 –6.7
Valproic acid, free 1 1 2 3 3 3 3 3 2 2 100.0
Vancomycin 57 59 63 62 66 67 71 70 70 74 29.8
Cyclosporine 47 48 48 46 48 47 47 48 50 52 10.6
Everolimus - - 8 8 8 8 10 10 11 12 -
Sirolimus 10 11 12 12 12 12 14 14 14 15 50.0
Tacrolimus (FK506) 57 59 60 61 66 65 67 68 72 73 28.1
Total no. of institutions 105 106 103 104 110 110 110 110 113 114 8.6
J Lab Med Qual Assur 2020;42:183~193 https://doi.org/10.15263/jlmqa.2020.42.4.183
© Lab Med Qual Assur