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pISSN 2384-2458 eISSN 2288-7261
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Evaluation Brief

J Lab Med Qual Assur 2018; 40(2): 109-111

Published online June 30, 2018

https://doi.org/10.15263/jlmqa.2018.40.2.109

Copyright © Korean Association of External Quality Assessment Service.

Performance Evaluation of Elecsys Vitamin D Total II Assay Using Roche Modular Analytics E170

Eun Jung Cho, Hyunjung Kim, Jeongho Park, Dongsik Kim, Youngjong Cha, Hae Kyung Lee

Department of Laboratory Medicine, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea

Correspondence to:Hae-Kyung Lee Departments of Laboratory Medicine, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271 Cheonbo-ro, Uijeongbu 11765, Korea Tel: +82-31-820-3159 Fax: +82-31-847-6266 E-mail: hkl@cathlic.ac.kr
교신저자: 이혜경 우)11765 의정부시 천보로 271, 가톨릭대학교 의정부성모병원 진단검사의학과 Tel: 031)820-3159, Fax: 031)847-6266, E-mail: hkl@cathlic.ac.kr

Received: March 23, 2018; Revised: March 28, 2018; Accepted: March 30, 2018

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We evaluated the performance of a recently developed immunoassay, Elecsys vitamin D total II assay (Roche Diagnostics GmbH, Germany). Precision, linearity, and comparison studies were performed according to the Clinical and Laboratory Standards Institute guidelines. Control materials, linearity materials, and patient samples were used for the evaluation. For the correlation study, liquid chromatography-tandem mass spectrometry was used as the comparative method. Total coefficients of variations of the analyte were between 5.1% and 9.6%. The results of linearity evaluation were also acceptable for the range tested. Correlations with comparative methods were good; however, the mean values of the Elecsys vitamin D assay were higher than those of liquid chromatography-tandem mass spectrometry. The overall analytical performance of the Elecsys vitamin D total II assay is acceptable for the immunology analyzer. Therefore, the Elecsys vitamin D total II assay is expected to be widely used.

Keywords: Vitamin D, Performance, Evaluation

혈청 및 혈장 중의 total 25-hydroxyvitamin D (25OH-D)를 전기화학발광법 원리로 측정하는 Elecsys vitamin D total II assay (Roche Diagnostics GmbH, Mannheim, Germany) 시약의 성능을 평가해보았다. 평가는 정밀도, 직선성 및 상관성에 대하여 이루어졌다. 정밀도는 두 가지 농도의 정도관리물질(PreciControl vitamin D total II level 1 lot no. 245476, level 2 lot no. 245477)를 이용하여 평가하였다. Clinical and Laboratory Standards Institute (CLSI) EP05-A3에 따라 각각의 정도관리물질을 20일 동안 매일 2 run씩, run당 2회씩 반복 측정하여 평가하였다[1]. 직선성은 CLSI EP06-A에 따라 평가하였다[2]. 5가지 농도를 가진 VALIDATE VIT D (Maine Standards Co., LLC, ME, USA)를 이용하여 각각 2회씩 반복 측정하여 그 결과를 이용하여 직선성을 평가하였다. 상관성은 CLSI EP09-A3에 따라서 표준검사법인 liquid chromatography-tandem mass spectrometry (LC-MS/MS)와 비교하였다[3]. 다양한 농도를 가진 40개 이상의 환자 검체를 이용하여 LC-MS/MS와 Roche Modular Analytics E170에서 측정하여 그 결과를 비교하였다. 각 종목별 정밀도 평가결과를 Table 1에 제시하였다. Fig. 1은 직선성 평가결과를 보여주는 그래프이고, Fig. 2는 상관성 평가결과를 보여주고 있다. 각 항목별 정밀도 평가결과, 저농도 및 고농도 정도관리물질의 total coefficients of variation는 5.1%와 9.6% 수준으로 모두 만족할 만한 수준이었다. 직선성 평가에서 임상적으로 중요한 농도 범위에서 slope 0.948, intercept 0.000으로 우수한 직선성이 확인되었고, 제조사가 제시하는 직선성의 범위를 만족하였다. LC-MS/MS와 상관성 평가결과 R=0.9456이었으나, 두 방법 간 mean bias는 8.4 ng/mL로, Elecsys vitamin D total II assay법의 vitamin D값이 LC-MS/MS법과 비교하여 높게 관찰되었다. 이는 자동화 면역측정법들이 25OH-D2 또는 vitamin D epimers에 의한 교차반응으로 25OH-D 농도가 높게 측정되는 기존의 연구들과 일치되는 소견이었다[4,5]. 따라서 Elecsys vitamin D total II는 임상검사실에서 vitamin D 측정 시약으로서 유용하게 사용할 수 있을 것으로 기대된다.

Table 1 . Precision profile of Elecsys vitamin D total II assay.

AnalyteQuality control levelMeanCoefficient of variation (%)

Within-runBetween-runBetween-dayTotal
Vitamin D (ng/mL)Low12.6348.20.05.09.6
High27.8023.50.03.85.1

Figure 1.

Linearity studies using Elecsys vitamin D total II assay.


Figure 2.

Comparison of the Elecsys vitamin D total II assay and LC-MS/MS method. The scatter plot (A) and bias plot (B) are shown. Abbreviation: LC-MS/MS, liquid chromatography-tandem mass spectrometry.


References

  1. Clinical and Laboratory Standards Institute. Evaluation of precision performance of quantitative measurement methods: approved guideline. 2nd ed. Wayne (PA): Clinical and Laboratory Standards Institute, 2014.
  2. Clinical and Laboratory Standards Institute. Evaluation of the linearity of quantitative measurement procedures: a statistical approach: approved guideline. Wayne (PA): Clinical and Laboratory Standards Institute, 2003.
  3. Clinical and Laboratory Standards Institute. Measurement procedure comparison and bias estimation using patient samples: approved guideline. 3rd ed. Wayne (PA): Clinical and Laboratory Standards Institute, 2013.
  4. Lee JH, Choi JH, Kweon OJ, Park AJ. Discrepancy between vitamin D total immunoassays due to various cross-reactivities. J Bone Metab 2015;22:107-12.
    Pubmed KoreaMed CrossRef
  5. Farrell CJ, Martin S, McWhinney B, Straub I, Williams P, Herrmann M. State-of-the-art vitamin D assays: a comparison of automated immunoassays with liquid chromatography-tandem mass spectrometry methods. Clin Chem 2012;58:531-42.
    Pubmed CrossRef

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