Analytical evaluation of the BioPlex® 2200 25-OH vitamin D total assay

• Published in: Clinical biochemistry Vol. 49; no. 9; pp. 723 - 725
• Main Authors: Abou El Hassan, Mohamed, Lin, Dan C.C., Earle, Tammy, Spencer, Megan, Blasutig, Ivan M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.2016
• Subjects: 25-Hydroxyvitamin D; 25-Hydroxyvitamin D 2 - blood; Biomarkers - blood; BioPlex; Calcifediol - blood; Chromatography, Liquid - methods; Humans; Immunoassay - methods; LC–MS/MS; Method comparison; Polymers - chemistry; Reproducibility of Results; Tandem Mass Spectrometry - methods; Vitamin D; Method comparison; Vitamin D; LC–MS/MS; BioPlex; 25-Hydroxyvitamin D
• ISSN: 0009-9120; 1873-2933
• DOI: 10.1016/j.clinbiochem.2016.03.010

Testing for 25-hydroxyvitamin D (25(OH)D) has increased dramatically over the past decade and several automated immunoassays exist to measure serum 25(OH)D. Here we assess the performance of the recently released automated Bio-Rad BioPlex® 2200 25-OH vitamin D immunoassay, claimed to equally detect 25(OH)D2 and 25(OH)D3, and compare its results against a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method and the well-established DiaSorin LIAISON® 25-OH vitamin D total immunoassay. Imprecision was determined using third party controls over 20days. Linearity over the claimed measuring range was assessed using admixtures of a high and a low patient pool. Correlation between the BioPlex and LC–MS/MS (n=137) or the LIAISON (n=56) was assessed using patient samples with varying amounts of 25(OH)D3 and/or 25(OH)D2. The total imprecision was 9.4%, 6.9% and 4.5% at concentrations of 39.4nmol/L, 70.6nmol/L and 242.8nmol/L, respectively. The assay was linear from 33.1–375.0nmol/L with a R2 of 0.993. Method comparison revealed a strong correlation between the BioPlex assay and LC–MS/MS for samples containing 25(OH)D2 alone (n=5; R2=0.999), 25(OH)D3 alone (n=119; R2=0.935) and both (n=13; R2=0.919). In samples tested by all three methods (n=56), the correlation between the BioPlex and the LIAISON (R2=0.853) was poorer than that of the BioPlex and LC–MS/MS (R2=0.942). The BioPlex assay is suitable for the measurement of total serum 25(OH)D. The strong correlation between the BioPlex assay and LC–MS/MS in detecting 25(OH)D2 and 25(OH)D3 provides evidence that the BioPlex assay is capable of the equivalent detection of both forms. [Display omitted] •We assess the performance of the Bio-Rad BioPlex® 2200 25-OH vitamin D immunoassay.•The assay demonstrates good correlation to LC–MS/MS.•The assay is able to equally detect both D2 and D3 forms of vitamin D.