Korean J Lab Med 21;3:345-5 DOI 1.3343/kjlm.21.3.4.345 Original Article Clinical Chemistry Comparison of HbA1c Analyzers: D-1, Variant II Turbo, Cobas Integra 8, and Afinion AS1 Jin Young Lee, M.D. 1, Ki Sook Hong, M.D. 1, and Sung Eun Cho, M.D. 2 Department of Laboratory Medicine 1, School of Medicine, Ewha Womans University, Seoul; Eone Reference Laboratory 2, Seoul, Korea Background : The purpose of this study was to evaluate the performance and agreement among HbA1c values measured using selected analyzers certified by the National Glycohemoglobin Standardization Program (NGSP) and standardized by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). Methods : HbA1c determined using D-1 (Bio-Rad, USA), Variant II Turbo (Turbo; Bio-Rad, USA), Cobas Integra 8 (Integra; Roche, Switzerland) and Afinion AS1 (Afinion; Axis-Shield, Norway) were compared with each other. Precision and method comparisons with Deming regression were evaluated according to CLSI recommendations. We also compared the HbA1c values obtained with each analyzer using either IFCC or NGSP methods by correlation analysis and kappa statistics. Results : The repeatability and method/device precisions of D-1 and Afinion were acceptable. The correlation coefficients of HbA1c were.986 for D-1 vs. Afinion,.997 for D-1 vs. Turbo,.988 for D-1 vs. Integra, and.991 for Integra vs. Afinion. The average biases of HbA1c Afinion (IFCC) and HbA1c Integra (IFCC) against HbA1c D-1 (NGSP) were -1.9% and -1.79%, respectively. Kappa agreement statistics for the three diabetic control group HbA1c values of less than 6.5%, 6.5%- 7.5%, and greater than 7.5% for D-1 vs. Turbo, D-1 vs. Integra, and D-1 vs. Afinion were.872,.836, and.833, respectively. Conclusions : The strong correlations and good clinical agreements of HbA1c between each analyzer expressed in terms of either NGSP or IFCC-derived NGSP indicate that these analyzers can be used interchangeably. (Korean J Lab Med 21;3:345-5) Key Words : HbA1c, National Glycohemoglobin Standardization Program (NGSP), International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), D-1, Afinion AS1, Cobas Integra 8, Variant II Turbo 서 론 는이용되고있다 [1-3]. 3 여가지가넘는 HbA1c 측정장비가개 HbA1c는 HbA의 b-사슬 N- 말단발린에포도당이결합된것으로당뇨병환자의 4-6주전혈당조절상태를알수있으며, 당뇨병의치료목표및당뇨환자의합병증의위험도를예측하 Received : October 16, 29 Manuscript No : KJLM9-12 Revision received : April 1, 21 Accepted : July 15, 21 Corresponding author : Ki Sook Hong, M.D. Department of Laboratory Medicine, Ewha Womans University Mokdong Hospital, 911-1 Mok-dong, Yangcheon-gu, Seoul 158-71, Korea Tel : +82-2-265-2822, Fax : +82-2-265-591 E-mail : kshong@ewha.ac.kr ISSN 1598-6535 The Korean Society for Laboratory Medicine 발되었기때문에표준화가필요하게되었으며, 대표적인 HbA1c 의표준화는 National Glycohemoglobin Standardization Program (NGSP) 과 International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) 가있다 [4-11]. Diabetes Control and Complication Trial (DCCT) 와 UK Prospective Diabetes Study (UKPDS) 에서는 NGSP법을따르고있으며, NGSP법은 Bio-Rex 7 레진을사용한이온교환 HPLC법에서 HbA1c 피크를측정하는방법이다. IFCC법의기준검사법은 HPLC/MS (HPLC/Mass spectrometry) 와 HPLC/ CE (HPLC/Capillary Electrophoresis) 이며, 검사원리는 HbA1c 의 N- 말단의 6개의펩타이드를효소 Glu-C로절단하여당화 345
346 Korean J Lab Med 21;3:345-5 혈색소와당화되지않은혈색소를측정하는것이다 [5-11]. IFCC 법으로측정한 HbA1c값은여러기관에서검증된만능방정식인 NGSP-HbA1c(%)=.915 [IFCC-HbA1c]+2.15을이용하여 NGSP 값으로변환할수있다 [7, 8]. 아직세계의많은기관의 HbA1c 측정법이 NGSP법을따르고있기때문에 IFCC법을따르는 HbA1c 측정기기는 NGSP값으로변환하여결과를보고하고있다. 따라서, 저자들은위만능방정식이실제현장에서 HbA1c값과임상적판단기준의일치도가어떠한가를확인하기위해우리나라에서많이사용되고있는 HbA1c 기기중에서 NGSP 인증을받은 D-1과 Variant II turbo (Turbo; Bio-Rad Laboratories, Inc., Hercules, CA, USA), IFCC법을따르며 NGSP 인증을받은 Cobas Integra 8 (Integra; Roche Diagnostics, Basel, Switzerland) 와 Afinion AS1 (Afinion; Axis-shield, Oslo, Norway) 을비교하였다. 재료및방법 1. 검체 D-1은 HbA1c값이 5.3-6.5%, 8.8-11.% 의 Lyphocheck Diabetes Bi-level 대조물질 (Bio-Rad) 을정밀도평가를위하여사용하였다. Afinion은 HbA1c값이 5.5-6.7%, 7.1-8.7% 의 Afinon TM HbA1c 대조물질 (Axis-Shield) 을사용하였다. 검사방법비교와회귀분석을위한검체는당뇨병환자 4명의 EDTA 전혈을사용하였다. 2. 사용기기 르며보정물질로보정한후에 NGSP 결과를내도록되어있다. Afinion과 Integra의 HbA1c의 NGSP값은교정식을사용하여 IFCC의 HbA1c값으로변환하였다. HbA1c값이 IFCC HbA1c값일때는기기명옆에 IFCC를붙여표시하였다. 3. 평가방법 D-1과 Afinion의정밀도평가는 CLSI EP5-A2의 1회측정평가법에따라저농도와고농도의정도관리물질을 2 작업일간측정하여재현성과방법 / 장비정밀도를측정하고실행표준편차 (performance SD).1을허용한도로정하였다 [15]. 작업일간정밀도는 2 작업일간측정한값의평균과표준편차를계산하여측정하였고 5% CV값을허용한도로정하였다. D-1 과 Afinion의검사방법비교는 CLSI EP9-A2에따라서환자 4명의 EDTA 전혈을각각 2회측정하여상관계수 (r), 기울기, y 절편, 계통오차및바이어스를평가하고데밍회귀분석을하였다 [16]. 검사방법비교에사용한검체는 D-1에서측정하였을때 HbA1c값이 4-6% 13 개, 6.1-7.% 6개, 7.1-8.% 4개, 그리고 8.1% 이상은 17개로비정상검체가 5% 이상이되도록하였다. D-1의 HbA1c값과 Turbo와 Integra의 HbA1c값의상관관계분석은 4명의검체를 Turbo와 Integra에서각각 1회씩측정하여회귀분석을하였다. 또한 D-1의 NGSP-HbA1c값과 Integra와 Afinion의 IFCC-HbA1c값은회귀분석을이용하여상관분석을하였고, 평균바이어스를계산하였다. 상관관계분석을이용하여계산된상관계수가.975 이상인경우상관성이우수한것으로평가하였다. D-1과 Turbo의검사원리는 HPLC이고 [12, 13], Integra의검사원리는동질면역검사법으로 HbA1c의 b 사슬에대한항체를이용한경쟁적면역검사법이다 [14]. Afinion의검사원리는 boronate 친화법으로 boronate는당화혈색소의 cis-diol과결합을하고 boronate와결합된혈색소와결합하지않은혈색소의반사율을측정하여 HbA1c를계산한다 (Table 1). 분석에사용한기기들은모두 NGSP 인증을받았거나 IFCC 표준화를따 4. 통계분석 D-1과 Turbo, Integra 및 Afinion의 HbA1c값의일치도비교는당뇨치료목표분류에따라 HbA1c값을 <6.5%, 6.5-7.5% 및 >7.5% 의 3개군으로나누어카파통계분석을하였다. 카파통계량은 >.8 매우우수, >.6 우수, >.4 양호, >.2 불량및.2은매우불량으로정의하였다. 통계분석은 SPSS Table 1. Characteristics of D-1, Variant II Turbo, Cobas Integra 8, and Afinion AS1 HbA1c analyzers Manufacturer Principle Standardization D-1 Bio-Rad HPLC NGSP certified/traceable to IFCC reference method Variant II Turbo Bio-Rad HPLC NGSP certified Cobas Integra 8 Roche Homogeneous immunoassay NGSP certified/ifcc standardized Afinion AS1 Axis Shield Boronate affinity assay NGSP certified/traceable to IFCC reference method Abbreviations: NGSP, National Glycohemoglobin Standardization Program; IFCC, International Federation of Clinical Chemistry.
Lee JY, et al., Comparison of HbA1c Analyzers 347 16 (SPSS Inc., Chicago, IL, USA) 을사용하였다. 다 (Fig. 1). 결 과 3. D-1, Turbo, Afinion 및 Integra 의 HbA1c 상관관계 1. D-1과 Afinion의정밀도 D-1과 Afinion의재현성과장비 / 방법정밀도는실행표준편차가.1일때모두적합하였다. D-1의저농도와고농도의작업일간정밀도는각각 1.14% 와.63% 이었고, Afinion의저농도와고농도의작업일간정밀도는 1.% 과.72% 이었다 (Table 2). 2. D-1과 Afinion의비교 D-1과 Afinion의상관계수 (r) 는.986이었고 (P<.1), 회귀방정식은 Afinion-HbA1c=.978[D-1-HbA1c]-.96이었다. 데밍회귀식은 Afinion-HbA1c=1.9[D-1-HbA1c]-.336 이었다. 측정표준오차는.41이었다. D-1의 HbA1c값이 4.%, 6.%, 7.% 및 8.% 일때 Afinion의 95% 신뢰구간은각각 3.64-3.99%, 5.66-5.89%, 6.65-6.85% 및 7.64-7.82% 이었 D-1과 Turbo 및 Integra의상관계수 (r) 은각각.997 (P<.1),.988 (P<.1) 이었고, 회귀방정식은각각 Turbo-HbA1c(%)=.985(D-1-HbA1c)-.3 및 Integra- HbA1c(%)=.898(D-1-HbA1c)+.648이었다. Integra와 Afinion의상관계수 (r) 은.991 (P<.1) 이었고, Afinion- HbA1c(%)=1.82(Integra-HbA1c)-.746이었다 (Fig. 2). Mean Afinion HbA1c (%) 16 14 12 1 8 6 y=1.9x-.336 r=.986 4 2 2 4 6 8 1 12 14 16 Mean D-1 HbA1c(%) A Mean Afion HbA1c-Mean D-1 HbA1c 1.5 1.5 5 1 15 -.5-1 -1.5 (D-1+Afinion)/2 (HbA1c%) Fig. 1. Comparison of the HbA1c method (A) using Afinion AS1 and D-1, which showed good correlation, but (B) with slight negative bias in Afinion AS1 HbA1c against D-1 evaluated according to CLSI EP9-A2 guidelines. B Table 2. Repeatability, device/method precision, and between-day precision of D-1 and Afinion AS1 HbA1c analyzers evaluated by CLSI EP5-A2 HbA1c analyzers Control HbA1c (%) 5.3-6.5 D-1 8.8-11. 5.5-6.7 Afinion AS1 Mean HbA1c (%) 5.92 1.27 5.94 7.79 Repeatability (Within-run precision) User SD.55.42.99.85 User variance.3.18.98.73 Performance claim SD.1.1.1.1 Performance variance.1.1.1.1 Degrees of freedom (R) 4 4 4 4 (I) (User variance/claim variance) *R 12. 7. 39. 29. (II) Critical Chi-square 55.8 55.8 55.8 55.8 Results Accepted Accepted Accepted Accepted Claim rejected (I>II) Claim accepted (I II) Device/method precision User SD.78.71.92.83 User variance.61.51.84.68 Performance claim SD.1.1.1.1 Performance variance.1.1.1.1 Degrees of freedom (R) 28 25 36 35 (I) (User variance/claim variance) *R 17. 12.7 3.2 23.8 (II) Critical Chi-square 41.3 37.7 51. 49.3 Results Accepted Accepted Accepted Accepted Claim rejected (I>II) Claim accepted (I II) Between-day precision (CV, %) 1.14.63 1..72 7.1-8.7
348 Korean J Lab Med 21;3:345-5 4. D-1 HbA1c (NGSP) 와 Afinion 및 Integra 의 HbA1c (IFCC) 차이 D-1의 HbA1c (NGSP) 와 Afinion의 HbA1c (IFCC) 의회귀방정식은 [Afinion HbA1c (IFCC)]=1.69 [D-1 HbA1c(NGSP)]- 2.454이었고, D-1의 HbA1c (NGSP) 와 Integra의 HbA1c (IFCC) 의회귀방정식은 [Integra HbA1c(IFCC)]=.982 [D-1 HbA1c (NGSP)]-1.64이었다. D-1의 HbA1c (NGSP) 에비해 Afinion 및 Integra의 HbA1c (IFCC) 의평균오차는각각 -1.9% 와 -1.79% 이었다 (Fig. 3). 5. 카파통계 HbA1c값을당뇨병의치료목표에따라분류할때, 일치도를평가하기위한카파통계량은 D-1 HbA1c와 Turbo HbA1c는.872, D-1 HbA1c와 Integra HbA1c는.836, D-1의 HbA1c NGSP of Variant II Turbo NGSP of Afinion AS1 16 14 12 1 8 6 4 2. 2. 4. 6. 8. 1. 12.14. 16. NGSP of D-1 A 16 14 12 1 y=.9858x-.3 r=.997 y=1.82x-.746 r=.991 8 6 4 2. 2. 4. 6. 8. 1. 12.14. 16. NGSP of Cobas Integra 8 NGSP of Cobas Integra 8 C 16. 14. 12. 1. y=.8984x+.6488 r=.988.8.6.4.2.. 2. 4. 6. 8. 1. 12.14. 16. NGSP of D-1 B Fig. 2. Comparison of HbA1c values using each NGSP method. (A) Variant II Turbo vs. D-1, (B) Cobas Integra 8 vs. D-1, and (C) Afinion AS1 vs. Cobas Integra 8, which all showed good correlation. Abbreviation: NGSP, National Glycohemoglobin Standardization Program. 와 Afinion 의 HbA1c 는.833 이었다 (Table 3). 고 HbA1c 측정법의표준화는미국, 영국의 NGSP, 스웨덴의 Mono-S, 일본의 JDS/JSCC 및유럽의 IFCC에의해이루어져있다 [7]. NGSP법은 DCCT와 UKPDS의표준검사법으로 NGSP 법의기준검사법은이온변환 HPLC법이다. 이온변환 HPLC 법으로 HbA1c를측정하는경우 HbA1c뿐만아니라다른당화혈색소및변종혈색소가측정되어참값과차이가있을수있다 [7]. IFCC법에서는 HbA1c를 bn1-deoxyfructosyl-hemoglobin 으로정의하고있으며기준검사법은 HPLC/MS와 HPLC/EP이고측정원리는전혈을용혈물로만들고 Glu-C로아미노말단의 6개의아미노산을절단한후 HPLC로당화혈색소와비당화혈색소를분리하여 mass spectrometry나모세관전기영동으로측정하는것이다 [5, 6]. 24년미국당뇨학회, 유럽당뇨연구학회와국제당뇨협회는 HbA1c의표준화와관련하여, IFCC법을 HbA1c 측정의새로운세계표준으로채택하였으며, HbA1c의표준화와그실행에대한연구가전세계적으로활발하게진행되고있다 [8-11]. 29년 HbA1c의국내외부정도관리에참여한기관의장비 IFCC of Afinion AS1 16. 14. 12. 1. 8. 6. 4. 2. y=1.695x-2.4548 r=.976 찰 IFCC of Cobas Integra 8 16. 14. 12. 1. 8. 6. 4. 2. y=.9818x-1.646 r=.988... 2. 4. 6. 8. 1. 12. 14. 16.. 2. 4. 6. 8. 1. 12. 14. 16. NGSP of D-1 A NGSP of D-1 B Fig. 3. Comparison of HbA1c methods. (A) Afinion AS1 (IFCC) vs. D-1 (NGSP) and (B) Cobas Integra 8 (IFCC) vs. D-1 (NGSP), which show large negative differences (-1.9% and - 1.79%, respectively). Abbreviations: NGSP, National Glycohemoglobin Standardization Program; IFCC, International Federation of Clinical Chemistry and Laboratory Medicine. Table 3. Agreement between HbA1c analyzers according to the three HbA1c levels HbA1c analyzers HbA1c (%) <6.5 6.5-7.5 >7.5 Total (N=4) Kappa statistics with D-1 D-1 15 4 21 4 - Variant II Turbo 16 5 19 4.872 Cobas Integra 8 16 7 17 4.836 Afinion AS1 16 6 18 4.833
Lee JY, et al., Comparison of HbA1c Analyzers 349 사용현황은 Variant II Turbo, 22.1%; HLC-723 G7, 22%; Nycocard, 14%; Cobas Integra, 5.4% 의순서로 HPLC 검사법을사용하는장비가주로사용되고있다. 검사원리가 HPLC 와면역검사법인장비들은 5% 이하의정밀도기준을만족하였고, 현장검사장비들은 6.9-8.1% 의정밀도를보여정도관리가필요한것으로생각되었다 [4, 17, 18]. 저자들은 HPLC법, boronate 친화법과면역법을검사원리로사용하는기기들사이에 HbA1c값을비교하였고 NGSP법인증을받은기기의 HbA1c값과 IFCC법을따르며 NGSP 인증을받은기기의 HbA1c값을비교하고일치도를분석하였다. CLSI EP5-A2를이용한 D-1과 Afinion의재현성과장비 / 방법의정밀도는적합하였으며, 정상농도및고농도의작업일간정밀도는모두 1.14% 이하로허용한도 5% 이내였다 [4, 18]. NGSP HbA1c값과 IFCC-변환 NGSP-HbA1c값사이에우수한상관성을보였고 (r.975), 카파통계량이.8 이상으로매우우수한일치도를보였기때문에기기들의 HbA1c 결과판정에문제가없었다. 또한 D-1의 HbA1c (NGSP) 값과 Afinion과 Integra의 HbA1c (IFCC) 값의평균오차는각각 -1.9% 와 -1.79% 로 1.5-2.% 의차이가있다는다른연구와같은결과를보여주었다 [6-1]. NGSP법의 HbA1c 참고치는정상 4-6%, 당뇨병의치료목표 <7%, 치료방법의변경 >8% 이고, IFCC법의 HbA1c 참고치는정상 3-4%, 치료목표 <5%, 치료방법의변경 >6% 이었다 [4, 5, 18, 19]. Dhatt 등 [2] 은 NGSP HbA1c-값과 IFCC값에서변환한 NGSP HbA1c값사이에우수한상관관계를가지며 (r 2 =.9372),.65의카파통계량을보여우수한일치도를보였으나, 당뇨병환자의혈당조절정도를완전, 만족, 미흡의세군으로나눌경우에통계적으로유의한차이 (P<.5) 가있기때문에호환성이없다고하였다. 그러나 Paisooksantivatana 등 [21] 은 NGSP HbA1c값과 IFCC값에서변환한 NGSP HbA1c값의상관계수가.98 (P<.1) 로우수한상관관계를가지며, 측정바이어스는 -.33%HbA1c (95%CI±.9%) 이었고당뇨병환자의혈당조절정도에대한분류에대해통계학적차이가없었기때문에호환성이있다고하였다. 본연구에서도 D-1과 Integra, D-1 과 Afinion의 NGSP HbA1c값과 IFCC값에서변환한 NGSP HbA1c값사이에강한상관관계갖고.8 이상의카파통계량을갖는매우우수한일치도를보였기때문에 NGSP HbA1c값과 IFCC값에서변환한 NGSP HbA1c값사이에호환성이있다고볼수있었다. HbA1c와관련된국제학회들은 IFCC법으로표준화하기로결정하였으며국내에서도 HbA1c 표준화와관련하여논의가이루어지고있다. IFCC법으로표준화가될경우, NGSP 법과참고치가다르므로당뇨병의진단및치료에혼란을초래할수있다. 이를피하기위한방법의하나로다른단위체계를사용하는것으로 NGSP HbA1c값은 % 를사용하고, IFCC HbA1c 값은 mmol/mol을사용하는것이논의된바있다 [22]. 결론적으로본연구에서평가한장비들은서로높은상관관계와우수한정밀도및일치도를보여 HbA1c값의 NGSP법과 IFCC-변환 NGSP HbA1c값들사이에호환성을확인할수있다. 요약배경 : National Glycohemoglobin Standardization Program (NGSP) 법인증을받거나 International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) 표준화를따르는 HbA1c 측정기기들의검사수행능력을비교평가하였다. 방법 : D-1 (Bio-Rad, USA), Variant II Turbo (Turbo; Bio-Rad, USA), Cobas Integra 8 (Integra; Roche, Switzerland) 과 Afinion AS1 (Afinion; Axis-Shield, Norway) 을서로비교하였다. CLSI 권고에따라정밀도검증및검사방법비교를하였고, 카파통계를이용하여일치도분석을하였다. 결과 : D-1과 Afinion의재현성과방법 / 장비정밀도는적합하였고, D-1과 Afinion, D-1과 Turbo 및 D-1과 Integra 의상관계수는각각.986,.997 및.988이었다. Integra와 Afinion의상관계수는.991이었다. D-1 (NGSP) 에비해 Afinion (IFCC) 및 Integra (IFCC) HbA1c값의평균오차는각각 -1.9%, -1.79% 이었다. HbA1c 측정값을당뇨병진단기준에의한분류에의하여 6.5% 미만, 6.5-7.5% 및 7.5 이상 세군으로나누었을때, D-1과 Turbo, D-1과 Integra 및 D- 1과 Afinion의카파통계량은각각.872,.836 및.833이었다. 결론 : 각기기들의 NGSP HbA1c값사이에높은상관성과일치도를보였고, NGSP HbA1c값과 IFCC-변환 NGSP HbA1c값사이의호환성을확인할수있었다. 참고문헌 1. Nathan DM, Singer DE, Hurxthal K, Goodson JD. The clinical information value of the glycosylated hemoglobin assay. N Engl J Med 1984;31:341-6. 2. Benjamin RJ and Sacks DB. Glycated protein update: implications of recent studies, including the diabetes control and complications
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