REPORT ON PROFICIENCY TESTING https://doi.org/10.15263/jlmqa.2018.40.2.85 Annual Report on the External Quality Assessment Scheme for Special Protein in Korea (2017) Hyung-Doo Park Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea Corresponding author: Hyung-Doo Park Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Korea Tel: +82-2-3410-0290 Fax: +82-2-3410-2719 E-mail: nayadoo@hanmail.net pissn: 2384-2458 eissn: 2288-7261 In 2017, the Korean Association of External Quality Assessment Service developed a special protein proficiency testing program that consisted of nine quantitative test items. This program was conducted twice a year using three-level control materials. Data and results of each test item were analyzed by respective institutions according to the test instruments. The report was prepared by dividing it into a common report that showed the characteristics of all the participating institutions and an organization-specific report that showed the assessment data of individual institutions. The following statistical data were presented: the number of participating institutions per group, mean, standard deviation, coefficient of variation, median, minimum value, and maximum value. The individual report was composed of a table, histogram, and Levey-Jennings chart showing the statistics for each test item. The results of the assessment of each institution and the statistical data for each classification are presented in a table, and a standard deviation index for both the company classification and classification by instruments was provided. Overall, no significant difference was observed between the number of participating institutions and the distribution of test equipment. The coefficient of variation tended to be relatively high for each test item because the concentration of quality control materials was low and the number of participating institutions was small. I believe that these statistical analysis data are useful for analyzing external quality control results of the institutions and selecting an immunoassay test instrument for special protein. (J Lab Med Qual Assur 2018;40:85-91) Key Words: Korean Association of External Quality Assessment Service, Laboratory proficiency testing, Special protein 서론 대한임상검사정도관리협회에서는 2016년부터새로운방식의차세대신빙도조사사업을시행하였는데, 가장큰변화는기존의분과중심운영체계에서 6개대분류, 46개프로그램단위별운영체계로전환하여검사항목을세분화한점이다. 임상화학분야는일반화학검사프로그램을비롯하여단백면역검사, 호르몬검사등 21개의프로그램으로구성되었는데, 이중에는기존체계하에임상화학분과위원회에서담당해왔던일반화학검사분야, 당화혈색소, 지질및크레아티닌에대한정확도기반신빙도조사사업등이포함되어있다 [1-4]. 단백면역검사프로그램에서시행되는검사항목은 ceruloplasmin 을포함한 9가지로선정되었다. 이에 2017년차세대신빙도조사사업으 로실시되었던단백변역검사에대한신빙도조사사업결과를분석하여보고하고자한다. 재료및방법 1. 대상단백면역검사프로그램은연 2회에걸쳐회차별로 3개의정도관리물질을사용하여수행되었다. 정도관리물질은냉장상태가유지될수있도록아이스팩이내장된특수제작박스에넣어참여등록기관을대상으로 5월 15일 (1차) 과 10월 16일 (2차) 에각각발송되었다 (Table 1). Copyright 2018 Korean Association of External Quality Assessment Service 85
2. 정도관리물질과검사항목정도관리물질은 Bio-Rad사의 Lyphochek Immunossay Control (Bio-Rad Laboratories, Hercules, CA, USA) 등사람혈청을기질로한액상제품을사용하였다. 검사항목은 ceruloplasmin, ferritin, transferrin, haptoglobin, prealbumin, alpha1-antitrypsin, C-reactive protein, anti-streptolysin O, rheumatoid factor 등 9개였으며, 이중 C-reactive protein 과 rheumatoid factor 등은정량및정성검사에대해 antistreptolysin O는정량, 반정량, 정성검사에대해시행하였다. 정도관리물질을수령한참여기관에서는검사시행후지정된회신마감일이내에대한임상검사정도관리협회신빙도조사사업홈페이지 (http://eqas.keqas.org) 에결과를입력하도록하였다. 3. 결과판정및분석각기관에서입력한검사항목별검사기기, 시약, 검사결과에따라통계분석을시행하였고, 이를전체참여기관의특성을보여주는공통보고서와개별기관의평가자료를보여주는기관별보고서로나누어보고하였다. 공통보고서는전체참여기관, 동일장비회사사용기관, 동일장비사용기관등 3단계로그룹화하여통계값을제시하였다 (Fig. 1). 전체참여기관에해당하는통계, 기기회사를기준분류로한그룹의통계, 특정검사기기로구분한그룹의통계를각각제시하였다. 제시된통계에는각그룹별참여기관수, 평균, 표준편차, 변동계수, 중앙값, 최소값, 최대값등이포함되어있다. 참여기관수, 중앙값, 최 소값과최대값등은이상치를제거하지않은모든참여기관의 수치를제시하였으며, 평균, 표준편차, 변동계수등은각그룹 에서이상치를제거한후산출된수치로계산하였다. 한편, 동 Table 1. Baseline data used in proficiency tests for special protein in 2017 Variable 1st Trial 2nd Delivery date 2017. 5. 15 2017. 10. 16 Response date 2017. 5. 15 5. 26 Test 2017. 10. 16 10. 27 Alpha1-antitrypsin 7 7 Anti-streptolysin O (quantitative) 165 168 Anti-streptolysin O (qualitative) 76 81 Anti-streptolysin O (semi-quantitative) 3 4 Ceruloplasmin 14 14 C-reactive protein (quantitative) 406 464 C-reactive protein (qualitative) 48 64 Ferritin 281 295 Haptoglobin 35 35 Prealbumin 26 24 Rheumatoid factor (quantitative) 334 363 Rheumatoid factor (qualitative) 100 134 Transferrin 31 30 Fig. 1. Summary report of the general statistics report for the special protein proficiency testing program of the 2017 Korean External Quality Assessment Service. 86 J Lab Med Qual Assur 2018;40:85-91 www.jlmqa.org
Fig. 2. An example of an individual institutional report for the special protein proficiency testing program of the 2017 Korean External Quality Assessment Service. 일그룹에속한기관수가 10개미만인경우에는평균, 표준편차, 변동계수등을제시하지않았고, 기관수가 3개미만인경우에는중앙값도제시하지않았다. 이상치는 Tukey rule을이용하여제거하였는데, 각해당분류에서 75 percentile 값 (Q3) 과 25 percentile 값 (Q1) 의차 (Q3-Q1; interquartile range, IQR) 의 1.5배를초과하여 Q1보다낮거나 Q3보다높은결과값 (<Q1 1.5 IQR 또는 >Q3+1.5 IQR) 으로설정하였다. 개별기관보고서는각검사항목별로통계치를보여주는표, 히스토그램, 레비-제닝스차트로구성하여일목요연하게볼수있도록하였다 (Fig. 2). 통계치를제시한표에는각기관의결과값과각분류별통계치를제시하고기준분류와세분류에서는표준편차지수 (standard deviation index, SDI) 를함께제시하였다. 전체참여기관자료와각그룹별참여기관의수가 10개미만일경우에는 SDI를제시하지않았다. 레비-제닝스차트는기준분류별 SDI를이용하여작성하였는데, 참여기관수가 10개미만인경우에는 SDI가제시되지않아서레비-제닝스차트에서도표시되지않았다. 히스토그램에서는전체참여기관의분포와기준분류별분포를제시하였고각기관의위치를표시하였다. 히스토그램의첫번째와마지막막대는각각전체참여기관의결과분포에서 2.5퍼센타일미만과 97.5퍼센타일이상에해당한다. 결과및고찰 단백면역검사프로그램에서 100개이상의기관이참여하는검사항목은 ferritin, C-reactive protein, anti-streptolysin O, rheumatoid factor 등 4가지였으며, 나머지 5항목은 7-35 기관의참여분포를보였다. 특히 alpha1-antitrypsin과 antistreptolysin O( 반정량 ) 검사는전체참여기관이각각 7곳과 4곳으로 10기관에미치지못하여통계분석을수행하지못하였다. 대부분의항목에서는전년도와비슷한수준의참여기관수를보였지만, C-reactive protein( 정량 ) 검사는 2016년 1 차신빙도조사에서 359기관, 2017년 1차에서 406기관, 2017 년 2차에서 464기관이참여하여참여기관증가폭이큰편이었다. 정성검사는 C-reactive protein, anti-streptolysin O, rheumatoid factor 등 3개항목에대해수행하였고, 모든정성검사항목에서 1차조사보다 2차조사에서참여기관의수가증가하였다. 정량검사항목들에대해두차례의신빙도조사에서전체참여기관의통계값을 Table 2에정리하였다. 단백면역검사는대부분전용시약과기기를사용하는데, 2차신빙도조사에서참여기관이 464곳으로가장많았던 C-reactive protein( 정량 ) 검사의경우, 18개회사에서 63종류의검사장비가사용되고있었다. C-reactive protein( 정량 ) 검사의전체기관정밀도는 coefficient of variation (CV, %) 가 CP-17-04, -05, -06 물질에서각각 9.8%, 6.8%, 5.9% 로 10% 이내를보였지만, 최 www.jlmqa.org J Lab Med Qual Assur 2018;40:85-91 87
Table 2. Proficiency test results for quantitative special protein in 2017 1st Test No. of participants Quality control no. Mean±standard deviation Coefficient of variation (%) Median (min max) Alpha1-antitrypsin 7 CP-17-01 ND ND 77 (71 83) CP-17-02 ND ND 125 (115 141) CP-17-03 ND ND 173 (154 202) Anti-streptolysin O 165 CP-17-01 71.38±6.65 9.32 72 (56 100) CP-17-02 126.1±9.01 7.14 127.6 (99.5 153.1) CP-17-03 334.84±31.27 9.34 325 (251.3 415.5) Ceruloplasmin 14 CP-17-01 16.66±0.62 3.72 16.9 (15.3 18.4) CP-17-02 32.25±1.46 4.52 32.5 (28.6 34.1) CP-17-03 45.99±2.39 5.2 45.5 (40.8 49.5) C-reactive protein 406 CP-17-01 0.55±0.06 11.67 0.6 (0.2 54) CP-17-02 2.62±0.19 7.24 2.6 (0.5 268) CP-17-03 4.76±0.33 6.85 4.8 (0.5 473) Ferritin 281 CP-17-01 31.7±3.8 12 33 (21 445) CP-17-02 198.2±39.4 19.9 188 (118 282) CP-17-03 315.6±65.4 20.7 298 (35 459) Haptoglobin 35 CP-17-01 68.8±2.2 3.2 68 (65 81) CP-17-02 154.4±5.1 3.3 154 (141 182) CP-17-03 232.1±9.2 4 234 (204 333) Prealbumin 26 CP-17-01 14.31±0.81 5.68 14.3 (12.9 15.8) CP-17-02 23.37±1.05 4.49 23.4 (21.3 27.2) CP-17-03 31.34±2.1 6.7 31.6 (28 38.1) Rheumatoid factor 334 CP-17-01 20.26±1.73 8.52 19.9 (10.4 57.6) CP-17-02 33.83±3.23 9.54 34 (19 49.6) CP-17-03 46.26±4.76 10.3 46.1 (18.6 64) Transferrin 31 CP-17-01 162±4.1 2.5 163 (144 177) 2nd CP-17-02 264.4±11.8 4.5 264 (240 284) CP-17-03 361.1±18.3 5.1 358 (325 401) Alpha1-antitrypsin 7 CP-17-04 ND ND 77 (67 78) CP-17-05 ND ND 127 (115 138) CP-17-06 ND ND 178 (163 221) Anti-streptolysin O 168 CP-17-04 75.9±5.91 7.8 78 (61 135) CP-17-05 135.1±8.19 6.1 137.6 (101 351) CP-17-06 312.1±18.65 6 315.5 (169 559) Ceruloplasmin 14 CP-17-04 15.3±1.53 10 15.8 (12.4 19.9) CP-17-05 32±2 6.3 32.8 (28.8 38.4) CP-17-06 45.8±2.36 5.2 47.5 (41.1 57.5) (Continued to the next page) 88 J Lab Med Qual Assur 2018;40:85-91 www.jlmqa.org
Table 2. Continued Test No. of participants Quality control no. Mean±standard deviation Coefficient of variation (%) Median (min max) C-reactive protein 464 CP-17-04 0.6±0.06 9.8 0.6 (0.1 66) CP-17-05 2.5±0.17 6.8 2.6 (0.8 272) CP-17-06 5±0.29 5.9 5.1 (1.5 525) Ferritin 295 CP-17-04 33±4.4 13 35 (22 2,630) CP-17-05 163±25.8 16 162 (100 1,258) CP-17-06 287±51.4 18 279 (144 2,102) Haptoglobin 35 CP-17-04 67±1.9 3 68 (61 73) CP-17-05 150±4.8 3 152 (139 261) CP-17-06 232±7.8 3 235 (169 262) Prealbumin 24 CP-17-04 14.3±0.64 4.4 14.4 (12 25.3) CP-17-05 24.6±1.2 4.9 24.8 (21 34.1) CP-17-06 33.5±2.05 6.1 33.1 (14.2 39.4) Rheumatoid factor 363 CP-17-04 20.4±1.7 8.4 20.3 (0.9 28.3) CP-17-05 32.9±3.13 9.5 33 (2.4 47.7) CP-17-06 44.9±4.62 10.3 45.7 (3.8 67.2) Transferrin 30 CP-17-04 155±5.2 3 157 (140 274) Abbreviation: ND, not determined. CP-17-05 274±11.1 4 274 (251 371) CP-17-06 364±14.1 4 365 (153 422) 소값과최대값의차이가무척큰경우가공통적으로관찰되었다. 2차신빙도조사의 C-reactive protein( 정량 ) CP-17-05 물질의경우, 464개전체참여기관의 CV (%) 는 6.8% 였지만, 최소값이 2.6 mg/dl, 최대값이 272 mg/dl로 100배이상의차이를보였으며, 이는실제로검사결과가차이를보였다기보다는검사결과입력오류이거나보고단위를착각하여발생했을것으로추정된다. C-reactive protein 검사결과를 SI unit (International System of Units, mg/l) 으로보고하려면 conventional unit (mg/dl) 에 conversion factor인 10을곱해야하는데, 신빙도조사결과입력시정확한단위를확인하지않고개별기관에서측정된결과와단위를그대로입력하는경우에오류가발생하게된다. 한편, 동일회사그룹이나동일기기사용그룹의숫자가적어서결과적합성여부를판단하는 SDI 등통계자료를분석할수없는경우가종종있었는데, 이런경우에는각기관에서전체참여기관자료등을참고하여결과가허용범위에드는지여부를개별적으로판단할필요가있겠다. 한편, 반정량및정성검사항목들에대한전체참여기관의통계값을 Table 3에정리하였다. C-reactive protein( 정성 ) 은두차례모두가장낮은농도에서합의된결과를도출하지못하였 는데, 이는 CP-17-01과 CP-17-04 물질이 0.5-0.6 mg/dl의평균값을보였기에판정기준치 (cutoff) 근처의값이어서이런결과가나왔을것으로추정된다. Rheumatoid factor는 1차신빙도조사에서세가지정도관리물질에대해모두합의된결과를이끌어내지못하였지만, 2차신빙도조사에서는 CP-17-06 물질에대해 positive 결과를나타냈다. 단백면역정성 / 반정량검사에사용된각각의정도관리물질은정량검사에사용된물질과동일하므로, 정성 / 반정량검사로보고하는기관에서는정량결과로보고하는전체참여기관의평균과표준편차등의통계값및개별정성검사시약의 cutoff 등을참고하여판단하여야한다. 예를들어, anti-streptolysin O CP-17-05 물질의경우, 전체참여기관 81곳의결과는 86.4% 가 negative로응답하여 negative가정답이었지만, 동일시약회사별분류에서는 TECO 사 (Anaheim, CA, USA) 제품을사용한 14기관중 negative로응답한기관이 78.6% 로기관간합의된결과를이끌어내지못하였다. 이와같이전체참여기관의판정결과와동일시약 / 기기그룹의판정결과가일치하지않거나결론을내지못하는경우에는여러가지상황을고려하여결과를신중하게해석할필요가있다. 정성검사의경우동일한시약이나장비를사용하는기관의수가적거나 www.jlmqa.org J Lab Med Qual Assur 2018;40:85-91 89
Table 3. Proficiency test results for qualitative special protein in 2017 Test No. of participants Quality control no. Positive (%) Negative (%) 1st Anti-streptolysin O 76 CP-17-01 0 100 CP-17-02 3.9 96.1 CP-17-03 81.6 18.4 C-reactive protein 48 CP-17-01 47.9 52.1 CP-17-02 100 0 CP-17-03 100 0 Rheumatoid factor 100 CP-17-01 43.0 57.0 CP-17-02 65.0 35.0 CP-17-03 70.0 30.0 2nd Anti-streptolysin O 81 CP-17-04 1.2 98.8 CP-17-05 13.6 86.4 CP-17-06 86.4 13.6 C-reactive protein 64 CP-17-04 50.0 50.0 CP-17-05 96.9 3.1 CP-17-06 98.4 1.6 Rheumatoid factor 134 CP-17-04 64.2 35.8 CP-17-05 48.5 51.5 CP-17-06 95.5 4.5 80% 이상의합의된결과가나오지않는다면정답을판정하기어려운경우가있는데, 지속적으로이와같은결과가나오는시약에대해서는회사나기관차원에서추가대책을마련할필요가있을것으로생각된다. 2016년부터단백면역검사프로그램은차세대신빙도조사사업운영방침에따라전과정이임상검사정도관리협회중앙에서일괄시행되었는데, 참여기관은일부항목에서전년에비해상당히증가하였으며동료그룹이적은경우에는외부정도관리결과를신중하게해석할필요가있다. REFERENCES 1. Jun SH, Song J, Song WH; Clinical Chemistry Subcommittee, Korean Association of External Quality Assessment Service. Annual report on the external quality assessment scheme for clinical chemistry in Korea (2015). J Lab Med Qual Assur 2016;38:111-9. 2. Jun SH, Song J; Clinical Chemistry Subcommittee, The Korean Association of External Quality Assessment Service. Annual report on the external quality assessment scheme for clinical chemistry in Korea (2014). J Lab Med Qual Assur 2015;37:115-23. 3. Jun SH, Song J; Clinical Chemistry Subcommittee; The Korean Association of Quality Assurance for Clinical Laboratory. Annual report on the external quality assessment scheme in clinical chemistry in Korea (2013). J Lab Med Qual Assur 2014;36:113-21. 4. Lee YW, Jeon BR, Kim JG, Jun SH, Yun YM, Chun S, et al. Annual report on the external quality assessment scheme for routine clinical chemistry in Korea (2016). J Lab Med Qual Assur 2017;39:61-75. 90 J Lab Med Qual Assur 2018;40:85-91 www.jlmqa.org
단백면역검사프로그램신빙도조사결과보고 (2017) 박형두성균관대학교의과대학삼성서울병원진단검사의학과 2017 년대한임상검사정도관리협회신빙도조사사업에서단백면역검사프로그램은총 9 개의정량검사항목으로구성되었고연 2 회에걸쳐회차별로 3 개의정도관리물질이이용되었다. 각기관에서입력된각검사항목에대한정보와결과를기반으로검사기기에따라분석하였다. 보고서는전체참여기관의특성을보여주는공통보고서와개별기관의평가자료를보여주는기관별보고서로나누어작성하였다. 제시된통계에는각그룹별참여기관수, 평균, 표준편차, 변동계수, 중앙값, 최소값과최대값이포함되도록하였고개별보고서는각검사항목별로통계치를보여주는표, 히스토그램과레비 - 제닝스차트로구성되도록하였다. 통계치를제시한표에는각기관의결과값과각분류별통계치를제시하고기준분류와세분류에서는표준편차지수를함께제시하였다. 참여기관의수와검사장비의분포에있어서는전체적으로전년도와큰차이는없었고, 각검사항목별회차별로정도관리물질의농도가낮고참여기관의수가적을수록변이계수는상대적으로높은경향을보였다. 각기관에서외부정도관리결과를해석하고단백면역검사장비를선택할때이통계분석자료가유용할것으로생각한다. (J Lab Med Qual Assur 2018;40:85-91) 교신저자 : 박형두우 )06351 서울시강남구일원로 81, 성균관대학교삼성서울병원진단검사의학과 Tel: 02)3410-0290, Fax: 02)3410-2719, E-mail: nayadoo@hanmail.net www.jlmqa.org J Lab Med Qual Assur 2018;40:85-91 91