The Assessment of Ultrasensitive HBsAg kit's Sensitivity level and Performance in Detection of Mutant Forms

Ultra-sensitive HBsAg IRMA 키트의 민감도 및 변이형 검출능 평가

Purpose: The DNA-type virus HBV, discovered by D. Dane and others in 1976, is approximately 42nm big and known as the main cause of liver-related diseases around the world. HBsAg has 4 kinds of subtypes including adw, adr, ayw and ayr and besides common antigen factor a, there are d, y, r, w. From the methods of serologically testing HBV, IRMA, EIA and CLIa were developed for testing HBsAg and are being used in examining the surface antigen of HBV. In this study, among the methods for testing HBV, the recently developed RIAKEY Ultrasensitive HBsAg IRMA kit's sensitivity level and performance in detection of mutant forms were measured and compared with CLIA. Materials and methods: Two certified reference materials, which are WHO 1st International Standard 1985(80/549) and WHO 2nd International Standard 2003(00/588. subtype adw2, genotypeA), were used in the examination and the sensitivity level was measured by diluting these materials from 0.08 IU/ml to 0.005 IU/ml. The materials for examining the detection of mutant forms included 9 kinds of subtype 'ad' and one kind of subtype 'ay' purchased from DSI company. Also, with the use of positive and negative samples, they was compared with CLIA. Result: Ultrasensitive HBsAg kit based on IRMA method showed the detection of up to 0.01 IU/ml not only for WHO 1st International Standard 1985(80/549) but also for WHO 2nd International Standard 2003(00/588. subtype adw2, genotypeA) and the sensitivity level was measured as 0.01 IU/ml by WHO standard. In testing the performance for detection of mutant forms, the 9 kinds of subtype 'ad' and one kind of subtype 'ay' mutant materials were detected, demonstrating the capacity of detecting various types of mutant forms. Conclusions: With the clinical importance of sensitivity level and performance in detection of mutant forms increasing in the field of HBsAg diagnosis, the examination of IRMA's effectiveness using RIA method in the aspects of the sensitivity level and performance in detection of mutant forms was carried out and its result is as follows. The sensitivity level was measured as 0.01 IU/ml by WHO standard and it was possible to measure various types of mutant forms with high sensitivity. Thus it is suggested that more speedy and accurate reports could be produced from a nuclear medicine laboratory for clinical practitioners requiring results of various situations.

배경 : B형간염표면항원(HBsAg)은 B형간염의 진단에 있어 가장 중요한 혈청학적 지표 중 하나이다. HBsAg 검사에 대한임상검사실의 수요에 맞추어 자동화 장비 및 검사법이 계속 개발되어 왔다. 본 연구는 국내에 보급된 RIAKEY, BNIBT, RIAKEY Ultra Sensitive HBsAg, ROCHE 키트의 민감도 및 변이형 검출능과 CLIA법의 CENTAUR 장비와 RIAKEY Ultra Sensitive HBsAg의 상관계수를 알아보고자 하였다. 방법 : WHO $1^{st}$ International Standard 1985(80/549), WHO $2^{nd}$ International Standard 2003 (00/588) 표준물질 2개를 이용하여 농도별 0.08, 0.04, 0.02, 0.01, 0.005 IU/ml 까지 계단희석을 시행하였으며, Subtype ad 9종, Subtype ay 변이시료 1종을 이용하여 RIAKEY, BNIBT, RIAKEY Ultra Sensitive HBsAg, ROCHE 키트를 이용하여 시행하였다. 그리고, 아형 검출에 사용된 변이시료 10종에 대한 IRMA법의 RIAKEY Ultra Sensitive HBsAg와 CLIA법의 CENTAUR 장비를 이용한 상관계수를 비교하였다. 결과 : 표준물질의 농도별 측정 시 WHO 0.01 PANEL 에서 Index 1.0 이상의 결과 값을 얻었으며, 그 결과 민감도는 0.01 IU/ml로 측정되었다. RIAKEY Ultra sensitve HBsAg 키트가 민감도측면에서 우수함을 알 수 있었다. RIAKEY Ultra sensitve HBsAg IRMA 키트에서는 adw2 9종과 ayw1 1종의 변이형 형태에 따라 모두 Index 1.0 이상으로 혈청중의 HBsAg을 100% 측정할수 있었다. RIAKEY Ultra sensitive HBsAg와 CLIA의 결과가 Y=1.0075 X + 1.2434, $R^2$=0.9982으로 우수한 상관성을 보였다. 결론 : 4세대인 IRMA법의 Ultra Sensitive HBsAg 키트로 혈청중의 HBsAg과 여러 가지 아형을 신속하고 정확히 측정하여 질병을 진단 할 수 있을 것으로 여겨진다.