대한임상병리학회지 : 제 20 권제 1 호 2000 Korean J Clin Pathol 2000; 20: 13-7 임상화학 Hb A1c 측정기기 VARIANT TM II 의평가 정화령 손향은 을지의과대학교노원을지병원임상병리과 Evaluation of VARIANT TM II Hemoglobin A1c Autoanalyzer Hwa Ryung Chung, M.D. and Hyang Eun Sohn, M.D. Department of Clinical Pathology, Nowon Eulji Hospital, Eulji University School of Medicine, Seoul, Korea Background : We evaluated newly introduced VARIANT TM II (Bio-Rad Laboratories, CA, USA) hemoglobin (Hb) A1c autoanalyzer, including bar code reading, cap-piercing system and automatic hemolyzing. It utilizes ion-exchange high performance liquid chromatography (HPLC) method. Methods : Linearity, precision, comparison with Hi-AUTOA1c TM HA-8121 (Kyoto Daiichi, Kagaku Co. Ltd, Kyoto, Japan) and analysis time were evaluated. The reference range was determined by VARIANT TM II from 120 healthy subjects. Results : Linearity through the range from 5.8% to 14.7% was good (r 2 =0.9909). The within-run coefficients of variation (CVs) for groups of low, middle and high level were 3.07%, 1.96% and 2.14% and between-day CVs for each group were 2.35%, 3.09% and 2.10%, respectively. Correlation equation between VARIANT TM II and Hi-AUTOA1c TM HA-8121 was VARIANT TM II=1.0886 (Hi- AUTOA1c TM HA-8121) + 0.4760% Hb A1c (r=0.9906). Two instruments were also compared by Altman and Bland s method and mean bias was 1.20. Analysis time of VARIANT TM II was 15.6 tests per hour compared with 14.8 tests of Hi-AUTOA1c TM HA-8121. The reference range in this study was 2.8-5.9% Hb A1c. Conclusions : VARIANT TM II showed the acceptable performance and advantage of calibration, and it was suitable for routine use in the clinical laboratory. (Korean J Clin Pathol 2000; 20: 13-7) Key words : Hemoglobin (Hb) A1c, Ion-exchange HPLC, Instrument evaluation 서 Hemoglobin (Hb) A1c는 Hb A1의약 80% 를차지하는당화혈색소의주된분획으로 Hb A에혈중 glucose가부착되어가역적인불안정한 pre-hb A1c단계를거쳐안정한 Hb A1c를형성한다 [1]. 당화혈색소는당뇨환자의과거 2-3개월의혈당을반영하므로장기간의혈당조절을추적관찰하는데유용하며 [2], 장기간에걸친당뇨합병증의발생을예측할수있는지표및치료 접수 : 1999 년 8 월 27 일접수번호 : KJCP1332 수정본접수 : 1999 년 11 월 10 일교신저자 : 정화령우 139-711 서울시노원구하계 1 동 280-1 을지의과대학교노원을지병원임상병리과전화 : 02-970-8324, Fax: 02-978-7040 E-mail : jhr7301@eulji.or.kr 론 의목표를설정하는지표로활용되고 [3, 4], 특이도가높아공복혈당과동시에측정하면당뇨병의선별검사로서유용하게쓰인다 [5]. Hb A1c의측정법으로는전하의차이를이용하는 ionexchange chromatography, high performance liquid chromatography (HPLC), electrophoresis, isoelectric focusing 등과, 구조의차이를이용한 affinity chromatography와 immunoassay, 그리고 colorimetry와 spectrophotometry같은화학적분석법등이있다 [1]. 이중 HPLC법이참고검사법으로제안되고있다 [1, 6, 7]. 최근개발된 VARIANT TM II (Bio-Rad Laboratories, CA, USA) 는 ion-exchange HPLC법을이용하고전처리단계가없이완전자동화된기기로서, 국내에서는아직이에대한평가가보고된바없다. 저자들은 VARIANT TM II의분석능력및기존 13
14 정화령 손향은 의 Hi-AUTOA1c TM HA-8121 (Kyoto Daiichi, Kagaku Co. Ltd, Kyoto, Japan) 과상관성을평가하여대치가능성을알아보았고참고치를설정하였기에보고하는바이다. 인 20-40세사이의남녀각 50명씩과종합검진자중에서혈당, 간기능및일반혈액검사의결과가정상인 41-60세사이의남녀각 10명씩을대상으로 VARIANT TM II로측정하여 nonparametric 방법으로참고치를구하였다 [11]. 대상및방법 1999년 7월중에을지병원임상병리과에 Hb A1c검사가의뢰된 132예의 EDTA 검체를이용하였다. 1. 직선성평가 결 과 1. 직선성평가기존의 Hi-AUTOA1c TM HA-8121로측정한 Hb A1c치가 5.8% 와 14.7% 인두검체를저농도와고농도의검체로하여 4:0, 3:1, 2:2, 1:3, 0:4의비율로섞어, 각각을 VARIANT TM II로 4 회반복측정한측정치와계산치를회귀분석하고회귀방정식과결정계수 (r 2 ) 를구하였다 [8]. 저농도와고농도의검체를 4:0, 3:1, 2:2, 1:3, 0:4의비율로섞어만든검체의계산된 Hb A1c 농도는각각 5.8%, 8.03%, 10.25%, 12.48%, 14.7% 이었다. 측정치와계산치로구한직선의회귀방정식은 y=0.9978x+0.2308이었고결정계수 (r 2 ) 는 0.9909이었다 (Fig. 1). 2. 정밀도평가 2. 정밀도평가기존기기로측정한 Hb A1c의측정치에따라검체를저농도군 (<7%), 중간농도군 (7-10%), 고농도군 (>10%) 으로각각나누어각군의혼주전혈 (pooled whole blood) 을만든후 20개의동일검체로나누어 2-6 에냉장보관하면서 20일간연속하여 VARIANT TM II로측정하였다. 상품화된정도관리물질을먼저측정하였고, 각군의검체는 2시간의간격을두고 2회검사하였으며각검사시에두번씩측정하여검사내정밀도 (within-run precision), 검사일간정밀도 (between-day precision) 및총정밀도 (total precision) 를각각구하였다 [9]. 3. 상관성평가기존기기에의한 Hb A1c의측정치가 4.4% 부터 14.0% 범위에속하는 70검체를선별하여 Hi-AUTOA1c TM HA-8121과 VARI- ANT TM II로각각 2회씩측정하여상관방정식과피어슨상관계수 (r) 를구하였다 [10]. 4. 분석속도두기기모두전처리과정이없으므로검체를장착하고검사를시작한시점부터마지막결과가나오기까지의시간을측정하여시간당처리한검체수를측정하였다. 5. 참고치설정본원의직원신체검사에서혈당및일반혈액검사결과가정상 검사내정밀도의변이계수는저농도군이 3.07%, 중간농도군이 1.96%, 고농도군이 2.14% 이었다. 검사일간정밀도는각각 Assay values (%Hb A1c) 16 14 12 10 8 6 y=0.9978x+0.2308 r 2 =0.9909 4 4 6 8 10 12 14 16 Calculated values (%Hb A1c) Fig. 1. Linearity of Hb A1c% analyzed by Variant TM II. Table 1. Precision for Hb A1c on the Variant TM II analyzer Level of % Hb A1c Low Medium High Mean (% Hb A1c) 5.4 8.5 12.2 Within-run CV(%) 3.07 1.96 2.14 Between-day CV(%) 2.35 3.09 2.10 Total precision CV(%) 4.13 4.27 3.30 Abbreviation: CV, coefficient of variation.
Hb A1c 측정기기 VARIANT TM II 의평가 15 2.35%, 3.09%, 2.10% 이었고총정밀도는각각 4.13%, 4.27%, 3.30% 이었다 (Table 1). 3. 상관성평가 4. 분석속도 Hi-AUTOA1c TM HA-8121은시간당 14.8검체를, VARI- ANT TM II는 15.6검체를분석하였다. 상관방정식은 VARIANT TM II=1.0886 (Hi-AUTOA1c TM HA-8121)+0.4760% Hb A1c이었고피어슨상관계수 (r) 는 0.9906이었다 (P <0.005) (Fig. 2). Altman and Bland의방법 [12] 에따라 VARIANT TM II의측정치에서 HA-8121의측정치를뺀차이들의평균은 1.20, 표준편차는 0.44, 95% 신뢰구간 (± 2SD) 은 0.32-2.08이었다 (Fig. 3). Variant TM II (%Hb A1c) 17 15 13 11 9 7 5 y=1.0886x+0.476 r=0.9906 3 3 5 7 9 11 13 15 17 Hi-AUTOA1c TM (%Hb A1c) Fig. 2. Comparison of Hb A1c results assayed by Variant TM II and Hi-AUTOA1c TM. 5. 참고치설정건강한성인 120명을대상으로신뢰구간을 95% 로하여구한 Hb A1c의참고범위는 2.8-5.9% 이었다. 고찰당화혈색소를측정하는여러가지검사법과기기들이개발되어검사능의평가와상관성에대한비교가보고되었다 [13-20]. 통상적으로 HPLC법이참고방법으로사용되고있으며 [1, 6, 7], Kobold 등 [21] 은 Hb A1c의분자구조에기초한 peptide mapping방법을새로운참고방법으로제안하였다. 본원에서기존에사용하고있는 Hi-AUTOA1c TM HA-8121은 ion-exchange HPLC법으로전처리단계가없는자동화된기기이나, 공인된정도관리물질이없어객관적인정도관리에어려움이있다. 최근개발된 VARIANT TM II는동일한검사법이며, 검체의전처리과정이없고, 모검체인진공채혈관을장착하면 cap piercing system에의한검체채취부터검사와결과보고까지의전단계가자동화되어있으므로이기기에대하여검토하게되었다. 본연구에서 VARIANT TM II는 5.8-14.7% Hb A1c 범위내에서우수한직선성을나타내었다. 검사내, 검사일간과총정밀도는모두변이계수가 5% 이하로우수하였다 [22]. 기존기기와상관성은상관방정식 (VARIANT TM II=1.0886 (Hi-AUTO A1c TM HA-8121)+0.4760% Hb A1c) 및피어슨상관계수 (r= Difference in %Hb A1c (Variant TM II-Hi-AUTO A1c TM ) 3 2.5 2 1.5 1 0.5 0 4 6 8 10 12 14 Average % Hb A1c by Variant TM II and Hi-AUTOA1c TM 2.08 (mean+2sd) 1.20 (mean) 0.32 (mean-2sd) Fig. 3. Relation between the difference and the mean % HbA1c by Variant TM II and Hi-AUTOA1c TM..
16 정화령 손향은 0.9906) 에의하면우수한것으로판단되었으나, Altman and Bland의방법 [12] 으로두기종의 Hb A1c 측정치를비교해보면 VARIANT TM II쪽이 Hi-AUTOA1c TM HA-8121보다평균 1.20% 가높게나타났고, 두예에서측정치의차이가 2.08 (mean+2sd) 이상이었다. 이러한측정치의차이는 calibration 요인또는 Hb A1c를불안정한 Hb A1c분획과분리하여측정영역을계산하는방식의차이에기인한것으로추정된다. 검체분석속도는시간당 VARIANT TM II가 15.6검체를, Hi- AUTOA1c TM HA-8121가 14.8검체를분석하여큰차이는없었다. 그러나 Hi-AUTOA1c TM HA-8121은모검체인진공채혈관의뚜껑을열고장착하여야하며, VARIANT TM II는그대로장착가능해서검체장착단계를포함한다면 VARIANT TM II가시간및인력이적게소모될것이다. VARIANT TM II에의한참고범위는 2.8-5.9% 로기존의참고치 (4.1-6.4%) 보다높을것으로추정하였으나오히려감소되었다. 기존의참고치는검사실에서자체적으로설정된것이아니므로객관적인평가가어려울것으로사료된다. 기존기기와상관성은만족스럽지못하나 VARIANT TM II는자체정도관리물질이있어객관성있는내부정도관리를시행할수있으므로더정확한결과를얻을수있고, 바코드인식이자동으로되며병원의전산화에쉽게적용할수있으므로결과및인력관리면에서효율적인기기로사료된다. 요약배경 : 기존의 hemoglobin (Hb) A1c 측정기기를대치하고자 ion-exchange high performance liquid chromatography (HPLC) 법을이용한자동화기기인 VARIANT TM II (Bio-Rad Laboratories, CA, USA) 의분석능에대하여평가하고자하였다. 방법 : VARIANT TM II의직선성, 정밀도, Hi-AUTOA1c TM HA-8121 (Kyoto Daiichi, Kagaku Co. Ltd, Kyoto, Japan) 과상관성및검체분석속도를평가하였고참고범위를구하였다. 결과 : 직선성은 Hb A1c의측정범위가 5.8-14.7% 사이에서결정계수가 0.9909로양호하였다. 검사내정밀도는저농도군이 3.07%, 중간농도군이 1.96%, 고농도군이 2.14% 이었고, 검사일간정밀도는각각 2.35%, 3.09%, 2.10% 이었고, 총정밀도는각각 4.13%, 4.27%, 3.30% 이었다. 두기기간의상관성평가에서상관방정식은 VARIANT TM II=1.0886 (Hi-AUTOA1c TM HA- 8121)+0.4760% Hb A1c이었고피어슨상관계수는 0.9906이었다. Altman and Bland의방법으로 VARIANT TM II의측정치에서 HA-8121의측정치를뺀차이들의평균은 1.20, 95% 신뢰구간 (±2SD) 은 0.32-2.08이었다. 분석속도는 Hi-AUTOA1c TM HA-8121은시간당 14.8검체를, VARIANT TM II는 15.6검체를분석하였다. VARIANT TM II로구한 Hb A1c의참고범위는 2.8-5.9% 이었다. 결론 : VARIANT TM II는자체정도관리물질이있으므로객 관성있는정도관리에의하여정확한결과를얻을수있고, 병원 의전산화에쉽게적용할수있으므로결과및인력관리면에서 효율적인기기로사료된다. 참고문헌 1. Sacks DB. Carbohydrates. In: Burtis CA and Ashwood ER, eds. Tietz textbook of clinical chemistry. 3rd ed. Philadelphia: WB Saunders, 1999: 750-808. 2. Nathan DM, Singer DE, Hurxthal K, Goodson JD. The clinical information value of the glycosylated hemoglobin assay. N Engl J Med 1984; 310: 341-6. 3. The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993; 329: 977-86. 4. U. K. Prospective Diabetes Study Group. U. K. prospective diabetes study 16: overview of 6 years therapy of type II diabetes: a progressive disease. Diabetes 1995; 44: 1249-58. 5. 최영식, 윤영호, 정화순, 최태열, 김춘원. 당뇨병환자진단에있어서 Hb A1c의유용성에관한연구. 대한임상병리학회지 1991; 11: 31-9. 6. Little RR, England JD, Wiedmeyer HM, McKenzie EM, Mitra R, Erhart PM, et al. Interlaboratory standardization of glycated hemoglobin determinations. Clin Chem 1986; 32: 358-60. 7. Bodor GS, Little RR, Garrett N, Brown W, Goldstein DE, Nahm MH. Standardization of glycohemoglobin determination in the clinical laboratory: three years of experience. Clin Chem 1992; 38: 2414-8. 8. National Committee for Clinical Laboratory Standards. Evaluation of the linearity performance of quantitative analytical methods. Proposed guideline. Document EP6-P. Vilanova, PA, National Committee for Clinical Laboratory Standards, 1986. 9. National Committee for Clinical Laboratory Standards. Evaluation of precision performance of clinical chemistry devices-second edition. Tentative guideline. Document EP5-T2. Vilanova, PA, National Committee for Clinical Laboratory Standards, 1992. 10. National Committee for Clinical Laboratory Standards. Method comparison and bias estimation using patient samples. Approved guideline. Document EP9-A. Vilanova, PA, National Committee for Clinical Laboratory Standards, 1995. 11. Solberg HE. Establishment and use of reference values. In: Burtis CA and Ashwood ER, eds. Tietz textbook of clinical chemistry. 3rd ed. Philadelphia: WB Saunders, 1999: 336-56. 12. Bland JM and Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1: 307-10. 13. 김종원, 김진규, 조성석. 고압이온교환액체크로마토그라피 (High
Hb A1c 측정기기 VARIANT TM II 의평가 17 Pressure Ion-Exchange Liquid Chromatography) 를이용한 Hb A1c의자동분석. 대한임상병리학회지 1989; 9: 19-22. 14. 강명서, 김정호, 권오헌, 이삼열. 친화성크로마토그래피법에의한당화혈색소의측정. 대한임상병리학회지 1991; 11: 363-7. 15. 양정선및김영기. Hb A1c Micro Column Test와 IMx Glycated Hemoglobin Assay의비교. 임상병리와정도관리 1993; 15: 103-9. 16. 박중경, 송정한, 박효순, 이규만. Hb A1c 검사용기기 MDMS-T TM 의평가. 임상병리와정도관리 1995; 17: 267-72. 17. 백세연, 전희선, 곽연식, 신옥현. Variant TM 이온교환고성능액체크로마토그래피법과 IMx R 이온포획정량법을이용한 Hb A1c의측정비교. 임상병리와정도관리 1995; 17: 261-5. 18. 정규영, 이만경, 김종원. Hb A1c 측정기기 TOSOH HLC-723GHb V A1c 2.2 TM 의평가. 대한임상병리학회지 1999; 19: 36-9. 19. Halwachs-Baumann G, Katzensteiner S, Schnedl W, Purstner P, Pieber T, Wilders-Truschnig M. Comparative evaluation of three assay systems for automated determination of hemoglobin A1c. Clin Chem 1997; 43: 511-7. 20. John WG, Braconnier F, Miedema K, Aulesa C, Piras G. Evaluation of the Menarini-Arkray HA 8140 hemoglobin A1c analyzer. Clin Chem 1997; 43: 968-75. 21. Kobold U, Jeppsson JO, Dulffer T, Finke A, Hoelzel W, Miedema K. Candidate reference methods for hemoglobin A1c based on peptide mapping. Clin Chem 1997; 43: 1944-51. 22. Larsen ML, Fraser CG, Petersen PH. A comparison of analytical goals for haemoglobin A1c assays derived using different strategies. Ann Clin Biochem 1991; 28: 272-8.