Discrepancy between radioimmunoassay and high performance liquid chromatography tandem-mass spectrometry for the analysis of androstenedione.
Anal Biochem 2014;
455:20-5. [PMID:
24708936 DOI:
10.1016/j.ab.2014.03.021]
[Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 03/19/2014] [Accepted: 03/28/2014] [Indexed: 11/20/2022]
Abstract
The discrepancy of results for the quantification of androstenedione in human serum between a radioimmunoassay (RIA) method and high performance liquid chromatography tandem-mass spectrometry (LC-MS/MS) was investigated. RIA overestimated concentrations compared to LC-MS/MS on 59 clinical samples (RIA=1.79×LC-MS/MS+0.94). RIA kit and LC-MS/MS calibrants were also determined by both methods. The RIA performed with improved accuracy on the calibrants (RIA=1.35×LC-MS/MS-0.28). Lipid, protein, electrolyte content, and pH of the two sets of calibrants were further investigated. The RIA calibrants contained little lipid material, while the LC-MS/MS calibrant material contained the same levels expected in normal serum/plasma. The pH and sex hormone binding globulin (SHBG) values were different between the RIA calibrants and the LC-MS/MS calibrant material (SHBG, 31±2 and 38±2nmol/l; pH, 8.27±0.18 and 8.66±0.03, respectively). No correlation was observed between androstenedione RIA and LC-MS/MS discrepancy and lipid or protein. LC-MS/MS sample preparation was tested for the removal of protein-bound material and recovery determined (99-108%). The corresponding RIA results overestimated androstenedione by 52-174% compared to LC-MS/MS. The results here demonstrate that LC-MS/MS is the more accurate method.
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