• BMB Reports
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• 제34권1호
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• pp.47-50
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• 2001

A one-step, two-site enzyme immunoassay was developed for measuring human alpha-fetoprotein (AFP) in serum and amniotic fluid using monoclonal antibodies (McAb) by eliminating the high-dose hook effect. Three McAbs that recognize different epitopes were selected among 16 different clones on the basis of epitope mapping, two for immobilization and one for horseradish peroxidase conjugation. This one-step immunoassay system is more convenient and rapid compared to a conventional two-step sandwich immunoassay system. It did not exhibit the hook effect to around 2.7 mg/ml of AFP, which is probably one of the highest concentrations of AFP in the serum. The dose-response curve of the system was linear to 500 mg/ml of AFP and the system could differentiate as low as 1 mg/ml of AFP The intra- and inter-assay variations were in an acceptable range; 95~104% and 97~105% respectively Its correlation with other commercial systems was around 95%.

• 핵의학기술
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• 제27권1호
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• pp.29-35
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• 2023

Purpose The concentration of PSA (Prostate Specific Antigen) after radical prostatectomy in prostate cancer patients is a predictor of biochemical recurrence, and the AUA (American Urological Association) is defined as biochemical recurrence when the concentration of PSA is measured at 0.2 ng/mL or more, and when the concentration is measured at 0.2 ng/mL or more at the retest. This standard is also applied our hospital. In this laboratory, the PSA reagent using IRMA (Immunoradiometric Assay) is used, and the sensitivity at a very low value was not as good as the reagent used in the department of laboratory medicine. This study aims to increase the reliability of the results by improving the precision and sensitivity of very low values. Materials and Methods As a reagent for the study, PSA reagent using IRMA was used. As a method to improve the precision and sensitivity of very low values, a variation method on the serum volume(25 uL, 50 uL, 100 uL, 200 uL) was studied, and variation usefulness evaluation was conducted. The evaluation items were compared the results of precision, analytical sensitivity, recovery rate, dilution test, high-dose hook effect test, parallel test and very low concentration values(n = 20). Results The validation results were displayed in the order of 25 uL, 50 uL, 100 uL, 200 uL. As the serum volume increased, it was confirmed that CV (Coefficient of Variation)(%) improved. Analytical sensitivity(ng/mL) was 0.038, 0.041, 0.017, 0.015 and recovery rate(%) was 101±3, 101±3, 99±2, 97±4. very low concentration values(ng/mL) between each volume(n=20) were 0.135±0.068, 0.076±0.050, 0.048±0.034, 0.046±0.034. and high dose hook effect appeared as the serum volume increased. Conclusion Through the variation usefulness evaluation, it was confirmed that as the serum volume increased, the precision and sensitivity improved at very low concentration values. However, it is necessary to pay special attention to the occurrence of high-dose hook effect as the serum volume increases. In the case of tests that requires very low concentration values, it is thought that the reliability of the result will be increased if the variation method is properly used after the variation usefulness evaluation.

• 핵의학기술
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• 제14권2호
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• pp.208-211
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• 2010

현재 본원은 TFB사의 CA19-9 항체가 bead에 코팅되어있는 CA19-9 IRMA 시약을 사용하고있다. 이번에 TFB사에서 새로 개발된 CA19-9 항체가 polystyrene test tube에 코팅된 CA 19-9 IRMA 시약이 기존 TFB사의 bead를 사용하는 시약을 대체하여 사용할 수 있는지 시약의 성능을 평가하였다. 본원과 서울대학교병원 환자 56명의 검체를 대상으로 하여 TFB사의 기존 bead 방법을 사용한 시약과 새로 개발된 coated tube를 사용한 시약을 비교하여 상관계수와 회귀식을 구하고 coated tube를 사용한 시약의 정밀도, 회수율, 직선성, 민감도, Hook effect 를 확인하였다. 저, 중, 고역가 검체의 검사내 정밀도는 4.1%, 4.0%, 4.2%이고 검사간 정밀도는 7.6%, 4.3%, 7.8%이며 회수율은 모두 $100{\pm}10%$이다. 직선성은 우수하였고 분석적민감도는 0.3U/mL이었으며 9,020,000 U/mL 농도에서는 Hook effect가 나타나지 않았다. 또한 TFB사의 기존 bead를 사용한 방법과 비교하여 상관관계를 분석한 결과, y=0.9185x-0.953, 상관계수 $R^2$=0.9779이었다. 이번 연구를 통해 본원은 TFB사에서 새로 개발된 coated tube CA19-9 IRMA 시약이 검사 시간과 검사 과정에서 간편화되고 검사시 자동화기기를 사용할 수 있으며 기존 bead를 사용한 시약에 대체하여 사용할 수 있다고 판단하였다.

• 핵의학기술
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• 제12권1호
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• pp.66-73
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• 2008

Purpose: CA 19-9 need to examine a number of sample volume, and the postwar 200 U/ml concentration hook effect appears slight. Thus, the antibody-antigen reaction, and by reducing the amount of (sample volume), they can hook effect to minimize the impact of the sample volume and relevance know, I saw the hook effect. In addition, the current maximum of using the standard concentration of the reagent in 240 U/ml increase more than the standard concentration can be seen knows. Material and Method: 5 U/ml and under, make a few low concentration of serum pool from the high concentration of the sample hook effect together with a standard concentration of about 500 to meet the production. The reagents used in experiments are currently using SNUH NM experiment. Orignal method along with the experiment is to 25 ul sample volume (1 / 4), 50 ul (1 / 2), 100 ul (Orignal method) in the experiment. My greatest concentration of the reagent concentration of approximately two times the standard concentration of production. When was the last to make the first experiment, as measured by the standard concentration after that. The new inspection information through a standard solution modified by entering values in them. Results: 100 ul, and to apply the new standard concentration y = 1.3021x - 10.97, $R^2$ = 0.9844. Overall, the results showed a similar orignal method. Because of the concentration in the value of more than 240 U/ml, but it is an overall value that can be made out of a similar value When I put the 50 ul y = 1.045x + 9.5861, $R^2$ = 0.9428. Overall orignal method and the results of a similar value. 50 ul, and to apply the new standard concentration y=1.2006x+11.252, $R^2$=0.9423. Showing a slightly lower value compared with orignal method. Because of the concentration in the value of more than 240 U/ml, but it is an overall value that can be made out of a similar value. When I put the man 25 ul y=0.6012x+24.755, $R^2$=0.4033. Results showed that very small amounts of sample are insecure inside and showed a lower middle cpm orignal method and showed a lot of mismatched. Conclusions: 25 ul of the sample volume is not possible to use the instability had, when I put the 50 ul of the orignal method can be used to show a similar concentration. The new values are slightly lower concentration, The new values are slightly lower concentration, concentration, which are likely due to the lack of data has had a little gap between the sample showed 80 to 200 U/ml additional experiments seem to do. Apply a new 100 ul concentration values are applied to a large crowd is not even in sight. But this way the concentration of 100 to more 400 U/ml gather further experiments should possible adds.