Effect of 25(OH) vitamin D reference method procedure (RMP) alignment on clinical measurements obtained with the IDS-iSYS chemiluminescent-based automated analyzer

Christine A. Simpson, Anna Maria Cusano, Jessica Bihuniak, Joanne Walker, Karl L. Insogna

Research output: Contribution to journalArticle

Abstract

The Vitamin D Standardization Program (VDSP) has identified ID-LC/MS/MS as the reference method procedure (RMP) for 25(OH) vitamin D and NIST Standard SRM2972 as the standard reference material (SRM). As manufacturers align their products to the RMP and NIST standard, a concern is that results obtained in aligned assays will be divergent from those obtained with pre-alignment assays. The Immunodiagnostic Systems Ltd.; chemiluminescent, 25(OH) vitamin D iSYS platform assay, was recently harmonized to the RMP. To determine the impact of standardization on results obtained with iSYS reagents, 119 single donor serum samples from eight different disease categories were analyzed in four non-standardized and two standardized iSYS assays. There were strong correlations between the four non-standardized and two standardized assays with Spearman's rank r values between 0.975 and 0.961 and four of the eight r values were >0.97. R2 values for the eight best-fit linear regression equations ranging between 0.947 and 0.916. None of the slopes were found to be significantly different from one another. Bland-Altman plots showed that the bias was comparable when each of the four non-standardized assays was compared to either of the standardized assays. When the data were segregated in values between 6 and 49 ng/mL (15-122 nmol/L) or between 50 and 100 ng/mL (125-250 nmol/L) significant associations remained between results obtained with non-standardized and standardized calibrators regardless of the absolute value. When five recent DEQAS unknowns were analyzed in one non-standardized and one standardized assay the mean percent difference from the NIST target in values obtained using standardized vs. non-standardized calibrators were not significantly different. Finally, strong and statistically significant associations between the results were obtained using non-standardized and standardized assays for six of eight clinical conditions. The only exceptions were hypocalcemia and breast cancer, which likely reflect the small sample sizes for each of these diseases. These initial data provide confidence that the move to a NIST standardized assay will have little impact on results obtained with the iSYS platform. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

Original languageEnglish (US)
Pages (from-to)41-46
Number of pages6
JournalJournal of Steroid Biochemistry and Molecular Biology
Volume148
DOIs
StatePublished - 2015

Fingerprint

Vitamin D
Assays
Hypocalcemia
Standardization
Sample Size
Linear Models
Breast Neoplasms
Education
Linear regression
Serum

Keywords

  • 25-hydroxy vitamin D
  • Harmonization
  • Standardization

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Endocrinology
  • Cell Biology
  • Molecular Biology
  • Endocrinology, Diabetes and Metabolism
  • Molecular Medicine
  • Medicine(all)

Cite this

Effect of 25(OH) vitamin D reference method procedure (RMP) alignment on clinical measurements obtained with the IDS-iSYS chemiluminescent-based automated analyzer. / Simpson, Christine A.; Cusano, Anna Maria; Bihuniak, Jessica; Walker, Joanne; Insogna, Karl L.

In: Journal of Steroid Biochemistry and Molecular Biology, Vol. 148, 2015, p. 41-46.

Research output: Contribution to journalArticle

@article{bcd0ce124eee4011b1b61969d332605a,
title = "Effect of 25(OH) vitamin D reference method procedure (RMP) alignment on clinical measurements obtained with the IDS-iSYS chemiluminescent-based automated analyzer",
abstract = "The Vitamin D Standardization Program (VDSP) has identified ID-LC/MS/MS as the reference method procedure (RMP) for 25(OH) vitamin D and NIST Standard SRM2972 as the standard reference material (SRM). As manufacturers align their products to the RMP and NIST standard, a concern is that results obtained in aligned assays will be divergent from those obtained with pre-alignment assays. The Immunodiagnostic Systems Ltd.; chemiluminescent, 25(OH) vitamin D iSYS platform assay, was recently harmonized to the RMP. To determine the impact of standardization on results obtained with iSYS reagents, 119 single donor serum samples from eight different disease categories were analyzed in four non-standardized and two standardized iSYS assays. There were strong correlations between the four non-standardized and two standardized assays with Spearman's rank r values between 0.975 and 0.961 and four of the eight r values were >0.97. R2 values for the eight best-fit linear regression equations ranging between 0.947 and 0.916. None of the slopes were found to be significantly different from one another. Bland-Altman plots showed that the bias was comparable when each of the four non-standardized assays was compared to either of the standardized assays. When the data were segregated in values between 6 and 49 ng/mL (15-122 nmol/L) or between 50 and 100 ng/mL (125-250 nmol/L) significant associations remained between results obtained with non-standardized and standardized calibrators regardless of the absolute value. When five recent DEQAS unknowns were analyzed in one non-standardized and one standardized assay the mean percent difference from the NIST target in values obtained using standardized vs. non-standardized calibrators were not significantly different. Finally, strong and statistically significant associations between the results were obtained using non-standardized and standardized assays for six of eight clinical conditions. The only exceptions were hypocalcemia and breast cancer, which likely reflect the small sample sizes for each of these diseases. These initial data provide confidence that the move to a NIST standardized assay will have little impact on results obtained with the iSYS platform. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.",
keywords = "25-hydroxy vitamin D, Harmonization, Standardization",
author = "Simpson, {Christine A.} and Cusano, {Anna Maria} and Jessica Bihuniak and Joanne Walker and Insogna, {Karl L.}",
year = "2015",
doi = "10.1016/j.jsbmb.2014.09.013",
language = "English (US)",
volume = "148",
pages = "41--46",
journal = "Journal of Steroid Biochemistry and Molecular Biology",
issn = "0960-0760",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Effect of 25(OH) vitamin D reference method procedure (RMP) alignment on clinical measurements obtained with the IDS-iSYS chemiluminescent-based automated analyzer

AU - Simpson, Christine A.

AU - Cusano, Anna Maria

AU - Bihuniak, Jessica

AU - Walker, Joanne

AU - Insogna, Karl L.

PY - 2015

Y1 - 2015

N2 - The Vitamin D Standardization Program (VDSP) has identified ID-LC/MS/MS as the reference method procedure (RMP) for 25(OH) vitamin D and NIST Standard SRM2972 as the standard reference material (SRM). As manufacturers align their products to the RMP and NIST standard, a concern is that results obtained in aligned assays will be divergent from those obtained with pre-alignment assays. The Immunodiagnostic Systems Ltd.; chemiluminescent, 25(OH) vitamin D iSYS platform assay, was recently harmonized to the RMP. To determine the impact of standardization on results obtained with iSYS reagents, 119 single donor serum samples from eight different disease categories were analyzed in four non-standardized and two standardized iSYS assays. There were strong correlations between the four non-standardized and two standardized assays with Spearman's rank r values between 0.975 and 0.961 and four of the eight r values were >0.97. R2 values for the eight best-fit linear regression equations ranging between 0.947 and 0.916. None of the slopes were found to be significantly different from one another. Bland-Altman plots showed that the bias was comparable when each of the four non-standardized assays was compared to either of the standardized assays. When the data were segregated in values between 6 and 49 ng/mL (15-122 nmol/L) or between 50 and 100 ng/mL (125-250 nmol/L) significant associations remained between results obtained with non-standardized and standardized calibrators regardless of the absolute value. When five recent DEQAS unknowns were analyzed in one non-standardized and one standardized assay the mean percent difference from the NIST target in values obtained using standardized vs. non-standardized calibrators were not significantly different. Finally, strong and statistically significant associations between the results were obtained using non-standardized and standardized assays for six of eight clinical conditions. The only exceptions were hypocalcemia and breast cancer, which likely reflect the small sample sizes for each of these diseases. These initial data provide confidence that the move to a NIST standardized assay will have little impact on results obtained with the iSYS platform. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

AB - The Vitamin D Standardization Program (VDSP) has identified ID-LC/MS/MS as the reference method procedure (RMP) for 25(OH) vitamin D and NIST Standard SRM2972 as the standard reference material (SRM). As manufacturers align their products to the RMP and NIST standard, a concern is that results obtained in aligned assays will be divergent from those obtained with pre-alignment assays. The Immunodiagnostic Systems Ltd.; chemiluminescent, 25(OH) vitamin D iSYS platform assay, was recently harmonized to the RMP. To determine the impact of standardization on results obtained with iSYS reagents, 119 single donor serum samples from eight different disease categories were analyzed in four non-standardized and two standardized iSYS assays. There were strong correlations between the four non-standardized and two standardized assays with Spearman's rank r values between 0.975 and 0.961 and four of the eight r values were >0.97. R2 values for the eight best-fit linear regression equations ranging between 0.947 and 0.916. None of the slopes were found to be significantly different from one another. Bland-Altman plots showed that the bias was comparable when each of the four non-standardized assays was compared to either of the standardized assays. When the data were segregated in values between 6 and 49 ng/mL (15-122 nmol/L) or between 50 and 100 ng/mL (125-250 nmol/L) significant associations remained between results obtained with non-standardized and standardized calibrators regardless of the absolute value. When five recent DEQAS unknowns were analyzed in one non-standardized and one standardized assay the mean percent difference from the NIST target in values obtained using standardized vs. non-standardized calibrators were not significantly different. Finally, strong and statistically significant associations between the results were obtained using non-standardized and standardized assays for six of eight clinical conditions. The only exceptions were hypocalcemia and breast cancer, which likely reflect the small sample sizes for each of these diseases. These initial data provide confidence that the move to a NIST standardized assay will have little impact on results obtained with the iSYS platform. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

KW - 25-hydroxy vitamin D

KW - Harmonization

KW - Standardization

UR - http://www.scopus.com/inward/record.url?scp=84925490470&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84925490470&partnerID=8YFLogxK

U2 - 10.1016/j.jsbmb.2014.09.013

DO - 10.1016/j.jsbmb.2014.09.013

M3 - Article

C2 - 25239596

AN - SCOPUS:84925490470

VL - 148

SP - 41

EP - 46

JO - Journal of Steroid Biochemistry and Molecular Biology

JF - Journal of Steroid Biochemistry and Molecular Biology

SN - 0960-0760

ER -