Comment on standardization for the assay values of serum vitamin B 12 as measured by automated analysis: Measurements using SRM 1955 as a reference material

Hiroshi Ihara, Toshiaki Watanabe, Naotaka Hashizume, Masayuki Totani, Kazuyuki Kamioka, Kimiko Onda, Satoshi Sunahara, Tomoko Suzuki, Mitsuharu Itabashi, Yoshikazu Aoki, Midori Ishibashi, Shozo Ito, Koji Ohashi, Tsuyoshi Enomoto, Kensuke Saito, Kayoko Saeki, Yoichi Nagamura, Tsutomu Nobori, Kouichi Hirota, Kinya FujishiroMasato Maekawa, Masakazu Miura, Takashi Kakinoki, Tomomi Ishii, Masakazu Watanabe, Yoshiji Ohta

Research output: Contribution to journalComment/debate

Abstract

In cooperation with the Japan Committee for Vitamin Laboratory Standards, the Committee on Nutrition of the Japan Society of Clinical Chemistry has issued a statement on the standardization in Japan of serum vitamin B12 measurements (sum of methycobalamin, adenosylcobalamin, hydroxocobalamin, and cyanocobalamin). The intra-laboratory and inter-method variations presented in the automated assays (i.e., Access, Centaur, and Elecsys) confounded the diagnosis of hypovitaminosis B12, and required standardization from the clinical and nutritional laboratories. Based on the study conducted by the World Health Organization (WHO), the National Institute of Standards and Technology (NIST) developed a Standard Reference Material (SRM 1955). The SRM 1955 was composed of three levels, the assigned values of which were 217 pg/mL for level 1, 488 pg/mL for level 2, and 474 pg/mL for level 3. Using values by Access related to the assigned value of SRM 1955 as a temporary comparison value, we investigated the possibility of standardization for the assay values of serum vitamin B12 as measured by the automated assays; this became necessary because the isotopic assay, Quantaphase, the established comparison method worldwide, is not sanctioned for use in Japan. When the observed values of SRM 1955 and 46 patient sera by Centaur and Elecsys were compared with the comparison values by Access, the values by SRM 1955 (levels 2 and 3) were plotted within a 95% prediction interval of the regression line. Because the regression equation was not applicable to the lower level of 217 pg/mL, the observed value of level 1 determined by Elecsys was plotted outside the lower 95% prediction limit. In addition, the normalized residuals obtained from level 2 by Centaur and level 3 by Elecsys were both within ± 3.0 enable us to conclude that the SRM 1955 had a physicochemical characterization similar to that of native serum. In the measurements of the 46 patient sera by Centaur and Elecsys, we corrected their observed values for the assigned value of SRM 1955, and compared those corrected values with the comparison values by Access. The biases between the comparison values and the values before and after correction were calculated. After the correction for SRM 1955, the biases were reduced in Centaur but increased in Elecsys. In the measurement by Centaur, the magnitudes of biases still present in the corrected values were at a level high enough to produce a misleading evaluation of hypovitaminosis B12. Based on the above observations, we concluded that a traceability chain to the comparison method should be established in the automated assays by using SRM 1955 as a reference material. We requested the preparation of an additional level of SRM 1955 having an assigned value of around 1000 pg/mL.

Original languageEnglish
Pages (from-to)58-69
Number of pages12
JournalJapanese Journal of Clinical Chemistry
Volume39
Issue number1
Publication statusPublished - 01-01-2010

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Vitamin B 12
Standardization
Assays
Japan
Serum
Hydroxocobalamin
Nutrition
Clinical Chemistry
Vitamins
Health
Technology

All Science Journal Classification (ASJC) codes

  • Clinical Biochemistry

Cite this

Ihara, Hiroshi ; Watanabe, Toshiaki ; Hashizume, Naotaka ; Totani, Masayuki ; Kamioka, Kazuyuki ; Onda, Kimiko ; Sunahara, Satoshi ; Suzuki, Tomoko ; Itabashi, Mitsuharu ; Aoki, Yoshikazu ; Ishibashi, Midori ; Ito, Shozo ; Ohashi, Koji ; Enomoto, Tsuyoshi ; Saito, Kensuke ; Saeki, Kayoko ; Nagamura, Yoichi ; Nobori, Tsutomu ; Hirota, Kouichi ; Fujishiro, Kinya ; Maekawa, Masato ; Miura, Masakazu ; Kakinoki, Takashi ; Ishii, Tomomi ; Watanabe, Masakazu ; Ohta, Yoshiji. / Comment on standardization for the assay values of serum vitamin B 12 as measured by automated analysis : Measurements using SRM 1955 as a reference material. In: Japanese Journal of Clinical Chemistry. 2010 ; Vol. 39, No. 1. pp. 58-69.
@article{3128e7c08e1b44448f1c164fe3fe1569,
title = "Comment on standardization for the assay values of serum vitamin B 12 as measured by automated analysis: Measurements using SRM 1955 as a reference material",
abstract = "In cooperation with the Japan Committee for Vitamin Laboratory Standards, the Committee on Nutrition of the Japan Society of Clinical Chemistry has issued a statement on the standardization in Japan of serum vitamin B12 measurements (sum of methycobalamin, adenosylcobalamin, hydroxocobalamin, and cyanocobalamin). The intra-laboratory and inter-method variations presented in the automated assays (i.e., Access, Centaur, and Elecsys) confounded the diagnosis of hypovitaminosis B12, and required standardization from the clinical and nutritional laboratories. Based on the study conducted by the World Health Organization (WHO), the National Institute of Standards and Technology (NIST) developed a Standard Reference Material (SRM 1955). The SRM 1955 was composed of three levels, the assigned values of which were 217 pg/mL for level 1, 488 pg/mL for level 2, and 474 pg/mL for level 3. Using values by Access related to the assigned value of SRM 1955 as a temporary comparison value, we investigated the possibility of standardization for the assay values of serum vitamin B12 as measured by the automated assays; this became necessary because the isotopic assay, Quantaphase, the established comparison method worldwide, is not sanctioned for use in Japan. When the observed values of SRM 1955 and 46 patient sera by Centaur and Elecsys were compared with the comparison values by Access, the values by SRM 1955 (levels 2 and 3) were plotted within a 95{\%} prediction interval of the regression line. Because the regression equation was not applicable to the lower level of 217 pg/mL, the observed value of level 1 determined by Elecsys was plotted outside the lower 95{\%} prediction limit. In addition, the normalized residuals obtained from level 2 by Centaur and level 3 by Elecsys were both within ± 3.0 enable us to conclude that the SRM 1955 had a physicochemical characterization similar to that of native serum. In the measurements of the 46 patient sera by Centaur and Elecsys, we corrected their observed values for the assigned value of SRM 1955, and compared those corrected values with the comparison values by Access. The biases between the comparison values and the values before and after correction were calculated. After the correction for SRM 1955, the biases were reduced in Centaur but increased in Elecsys. In the measurement by Centaur, the magnitudes of biases still present in the corrected values were at a level high enough to produce a misleading evaluation of hypovitaminosis B12. Based on the above observations, we concluded that a traceability chain to the comparison method should be established in the automated assays by using SRM 1955 as a reference material. We requested the preparation of an additional level of SRM 1955 having an assigned value of around 1000 pg/mL.",
author = "Hiroshi Ihara and Toshiaki Watanabe and Naotaka Hashizume and Masayuki Totani and Kazuyuki Kamioka and Kimiko Onda and Satoshi Sunahara and Tomoko Suzuki and Mitsuharu Itabashi and Yoshikazu Aoki and Midori Ishibashi and Shozo Ito and Koji Ohashi and Tsuyoshi Enomoto and Kensuke Saito and Kayoko Saeki and Yoichi Nagamura and Tsutomu Nobori and Kouichi Hirota and Kinya Fujishiro and Masato Maekawa and Masakazu Miura and Takashi Kakinoki and Tomomi Ishii and Masakazu Watanabe and Yoshiji Ohta",
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Ihara, H, Watanabe, T, Hashizume, N, Totani, M, Kamioka, K, Onda, K, Sunahara, S, Suzuki, T, Itabashi, M, Aoki, Y, Ishibashi, M, Ito, S, Ohashi, K, Enomoto, T, Saito, K, Saeki, K, Nagamura, Y, Nobori, T, Hirota, K, Fujishiro, K, Maekawa, M, Miura, M, Kakinoki, T, Ishii, T, Watanabe, M & Ohta, Y 2010, 'Comment on standardization for the assay values of serum vitamin B 12 as measured by automated analysis: Measurements using SRM 1955 as a reference material', Japanese Journal of Clinical Chemistry, vol. 39, no. 1, pp. 58-69.

Comment on standardization for the assay values of serum vitamin B 12 as measured by automated analysis : Measurements using SRM 1955 as a reference material. / Ihara, Hiroshi; Watanabe, Toshiaki; Hashizume, Naotaka; Totani, Masayuki; Kamioka, Kazuyuki; Onda, Kimiko; Sunahara, Satoshi; Suzuki, Tomoko; Itabashi, Mitsuharu; Aoki, Yoshikazu; Ishibashi, Midori; Ito, Shozo; Ohashi, Koji; Enomoto, Tsuyoshi; Saito, Kensuke; Saeki, Kayoko; Nagamura, Yoichi; Nobori, Tsutomu; Hirota, Kouichi; Fujishiro, Kinya; Maekawa, Masato; Miura, Masakazu; Kakinoki, Takashi; Ishii, Tomomi; Watanabe, Masakazu; Ohta, Yoshiji.

In: Japanese Journal of Clinical Chemistry, Vol. 39, No. 1, 01.01.2010, p. 58-69.

Research output: Contribution to journalComment/debate

TY - JOUR

T1 - Comment on standardization for the assay values of serum vitamin B 12 as measured by automated analysis

T2 - Measurements using SRM 1955 as a reference material

AU - Ihara, Hiroshi

AU - Watanabe, Toshiaki

AU - Hashizume, Naotaka

AU - Totani, Masayuki

AU - Kamioka, Kazuyuki

AU - Onda, Kimiko

AU - Sunahara, Satoshi

AU - Suzuki, Tomoko

AU - Itabashi, Mitsuharu

AU - Aoki, Yoshikazu

AU - Ishibashi, Midori

AU - Ito, Shozo

AU - Ohashi, Koji

AU - Enomoto, Tsuyoshi

AU - Saito, Kensuke

AU - Saeki, Kayoko

AU - Nagamura, Yoichi

AU - Nobori, Tsutomu

AU - Hirota, Kouichi

AU - Fujishiro, Kinya

AU - Maekawa, Masato

AU - Miura, Masakazu

AU - Kakinoki, Takashi

AU - Ishii, Tomomi

AU - Watanabe, Masakazu

AU - Ohta, Yoshiji

PY - 2010/1/1

Y1 - 2010/1/1

N2 - In cooperation with the Japan Committee for Vitamin Laboratory Standards, the Committee on Nutrition of the Japan Society of Clinical Chemistry has issued a statement on the standardization in Japan of serum vitamin B12 measurements (sum of methycobalamin, adenosylcobalamin, hydroxocobalamin, and cyanocobalamin). The intra-laboratory and inter-method variations presented in the automated assays (i.e., Access, Centaur, and Elecsys) confounded the diagnosis of hypovitaminosis B12, and required standardization from the clinical and nutritional laboratories. Based on the study conducted by the World Health Organization (WHO), the National Institute of Standards and Technology (NIST) developed a Standard Reference Material (SRM 1955). The SRM 1955 was composed of three levels, the assigned values of which were 217 pg/mL for level 1, 488 pg/mL for level 2, and 474 pg/mL for level 3. Using values by Access related to the assigned value of SRM 1955 as a temporary comparison value, we investigated the possibility of standardization for the assay values of serum vitamin B12 as measured by the automated assays; this became necessary because the isotopic assay, Quantaphase, the established comparison method worldwide, is not sanctioned for use in Japan. When the observed values of SRM 1955 and 46 patient sera by Centaur and Elecsys were compared with the comparison values by Access, the values by SRM 1955 (levels 2 and 3) were plotted within a 95% prediction interval of the regression line. Because the regression equation was not applicable to the lower level of 217 pg/mL, the observed value of level 1 determined by Elecsys was plotted outside the lower 95% prediction limit. In addition, the normalized residuals obtained from level 2 by Centaur and level 3 by Elecsys were both within ± 3.0 enable us to conclude that the SRM 1955 had a physicochemical characterization similar to that of native serum. In the measurements of the 46 patient sera by Centaur and Elecsys, we corrected their observed values for the assigned value of SRM 1955, and compared those corrected values with the comparison values by Access. The biases between the comparison values and the values before and after correction were calculated. After the correction for SRM 1955, the biases were reduced in Centaur but increased in Elecsys. In the measurement by Centaur, the magnitudes of biases still present in the corrected values were at a level high enough to produce a misleading evaluation of hypovitaminosis B12. Based on the above observations, we concluded that a traceability chain to the comparison method should be established in the automated assays by using SRM 1955 as a reference material. We requested the preparation of an additional level of SRM 1955 having an assigned value of around 1000 pg/mL.

AB - In cooperation with the Japan Committee for Vitamin Laboratory Standards, the Committee on Nutrition of the Japan Society of Clinical Chemistry has issued a statement on the standardization in Japan of serum vitamin B12 measurements (sum of methycobalamin, adenosylcobalamin, hydroxocobalamin, and cyanocobalamin). The intra-laboratory and inter-method variations presented in the automated assays (i.e., Access, Centaur, and Elecsys) confounded the diagnosis of hypovitaminosis B12, and required standardization from the clinical and nutritional laboratories. Based on the study conducted by the World Health Organization (WHO), the National Institute of Standards and Technology (NIST) developed a Standard Reference Material (SRM 1955). The SRM 1955 was composed of three levels, the assigned values of which were 217 pg/mL for level 1, 488 pg/mL for level 2, and 474 pg/mL for level 3. Using values by Access related to the assigned value of SRM 1955 as a temporary comparison value, we investigated the possibility of standardization for the assay values of serum vitamin B12 as measured by the automated assays; this became necessary because the isotopic assay, Quantaphase, the established comparison method worldwide, is not sanctioned for use in Japan. When the observed values of SRM 1955 and 46 patient sera by Centaur and Elecsys were compared with the comparison values by Access, the values by SRM 1955 (levels 2 and 3) were plotted within a 95% prediction interval of the regression line. Because the regression equation was not applicable to the lower level of 217 pg/mL, the observed value of level 1 determined by Elecsys was plotted outside the lower 95% prediction limit. In addition, the normalized residuals obtained from level 2 by Centaur and level 3 by Elecsys were both within ± 3.0 enable us to conclude that the SRM 1955 had a physicochemical characterization similar to that of native serum. In the measurements of the 46 patient sera by Centaur and Elecsys, we corrected their observed values for the assigned value of SRM 1955, and compared those corrected values with the comparison values by Access. The biases between the comparison values and the values before and after correction were calculated. After the correction for SRM 1955, the biases were reduced in Centaur but increased in Elecsys. In the measurement by Centaur, the magnitudes of biases still present in the corrected values were at a level high enough to produce a misleading evaluation of hypovitaminosis B12. Based on the above observations, we concluded that a traceability chain to the comparison method should be established in the automated assays by using SRM 1955 as a reference material. We requested the preparation of an additional level of SRM 1955 having an assigned value of around 1000 pg/mL.

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