TY  - JOUR
AB  - BACKGROUND: There is growing interest in the measurement of growth differentiation factor 15 (GDF-15) in a range of disorders associated with cachexia. We undertook studies to determine whether a common histidine (H) to aspartate (D) variant at position 202 in the pro-peptide (position 6 in the mature peptide) interfered with its detection by 3 of the most commonly used immunoassays. METHODS: Three synthetic GDF-15-forms (HH homo-, HD hetero-, and DD-homodimers) were measured after serial dilution using Roche Elecsys®, R&D QuantikineTM ELISA, and MSD R&D DuoSet® immunoassays. GDF-15 concentrations were measured by the Roche and the MSD R&D immunoassays in 173 genotyped participants (61 HH homozygotes, 59 HD heterozygotes, and 53 DD homozygotes). For the comparative statistical analyses of the GDF-15 concentrations, we used non-parametric tests, in particular Bland-Altman difference (bias) plots and Passing-Bablok regression. The bioactivity of the 2 different homodimers was compared in a cell-based assay in HEK293S-SRF-RET/GFRAL cells. RESULTS: The Roche assay detected H- and D-containing peptides similarly but the R&D reagents (Quantikine and DuoSet) consistently underreported GDF-15 concentrations in the presence of the D variant. DD dimers had recoveries of approximately 45% while HD dimers recoveries were 62% to 78%. In human serum samples, the GDF-15 concentrations reported by the R&D assay were a median of 4% lower for HH, a median of 36% lower for HD, and a median of 61% lower for DD compared to the Roche assay. The bioactivities of the HH and DD peptides were indistinguishable. CONCLUSIONS: The D variant of GDF-15 substantially affects its measurement by a commonly used immunoassay, a finding that has clear implications for its interpretation in research and clinical settings.
AU  - Karusheva, Y.*
AU  - Ratcliff, M.*
AU  - Mörseburg, A.*
AU  - Barker, P.*
AU  - Melvin, A.*
AU  - Sattar, N.*
AU  - Burling, K.*
AU  - Backmark, A.*
AU  - Roth, R.*
AU  - Jermutus, L.*
AU  - Guiu-Jurado, E.
AU  - Blüher, M.
AU  - Welsh, P.*
AU  - Hyvönen, M.E.*
AU  - O'Rahilly, S.*
C1  - 65657
C2  - 52872
SP  - 1388-1400
TI  - The common H202D variant in GDF-15 does not affect its bioactivity but can significantly interfere with measurement of Its circulating levels.
JO  - J. Appl. Lab. Med.
VL  - 7
IS  - 6
PY  - 2022
SN  - 2576-9456
ER  - 

TY  - JOUR
AB  - Background: The increasing relevance of individual bile acids quantification in biological samples requires analytical standardization to guarantee robustness and reliability of laboratory results. We have organized the first international ring trial, carried out in 12 laboratories, to evaluate the newly developed LC-MS/MS-based test kit for bile acid analysis. Methods: Each laboratory received a Biocrates® Bile Acids Kit including system suitability test (SST) protocol. The kit is designed to analyze 16 individual human and 19 mouse bile acids. A set of 9 human and mouse plasma samples was measured in replicates. Laboratories were first required to pass the acceptance criteria for the SST. Within the subset of laboratories passing SST criteria, we evaluated how many laboratories met the target criteria of 80% of reported values with a relative accuracy within the 70%-130% range and analytical precisions (%CV) below 30%. Results: A total of 12 of 16 participating laboratories passed the SST as the prerequisite to enter the ring trial. All 12 laboratories were then able to successfully run the kit and ring trial samples. Of the overall reported values, 94% were within 70%-130% relative accuracy range. Mean precision was 8.3% CV. The condition of CV <30% was fulfilled by 99% of the reported values. Conclusions: The first publically available interlaboratory ring trial for standardized bile acids quantification in human and mouse plasma samples showed very good analytical performance, within acceptance criteria typically applied in the preclinical environment. The kit is therefore suitable for standardized quantitative bile acid analysis and the establishment of reference values.
AU  - Pham, H.T.*
AU  - Arnhard, K.*
AU  - Asad, Y.J.*
AU  - Deng, L.*
AU  - Felder, T.K.*
AU  - St John-Williams, L.*
AU  - Kaever, V.*
AU  - Leadley, M.*
AU  - Mitro, N.*
AU  - Muccio, S.*
AU  - Prehn, C.
AU  - Rauh, M.*
AU  - Rolle-Kampczyk, U.*
AU  - Thompson, K.*
AU  - Uhl, O.*
AU  - Ulaszewska, M.*
AU  - Vogeser, M.*
AU  - Wishart, D.S.*
AU  - Koal, T.*
C1  - 68528
C2  - 0
SP  - 129-142
TI  - Inter-Laboratory Robustness of Next-Generation Bile Acid Study in Mice and Humans: International Ring Trial Involving 12 Laboratories.
JO  - J. Appl. Lab. Med.
VL  - 1
IS  - 2
PY  - 2016
SN  - 2576-9456
ER  -