Imprecision
The lowest coefficients of variation for precision within and between series over the whole tested concentration range were found for the LIAISON CLIA and LC-MS/MS method. Then followed the RIA. The Immulite CLIA showed the highest overall values and thus the lowest precision. A detailed list of all calculated variation coefficients is provided in Table 1 (A).
Sensitivity
The limit of blank (LoB), limit of detection (LoD) and limit of quantification (LoQ) were determined for all methods. The RIA proved to be the most analytically sensitive method, followed by LC-MS/MS. The LIAISON CLIA proved to be less sensitive, the most insensitive method was by far the Immulite CLIA. All determined determination limits are summarized in Table …show more content…
Passing-Bablok regression of the LC-MS/MS versus the LIAISON was y=0.65x-0.01, Pearson`s coefficient of correlation r=0.975 (n=175); LCMSMS versus Immulite was y=0.60x+0.21, r=0.746 (n=125), LC-MS/MS versus RIA was y=0.75x+0.01, r=0.956 (n=80); LIAISON versus Immulite was y=0.96x+0.25, r=0.745 (n=135); LIAISON versus RIA was y=1.17x+0.01, r=0.954 (n=79); and Immulite versus RIA was y=1.29x-0.34, r=0.810 (n=40). All ratios were assumed to be linear. The Immulite CLIA was not interchangeable with the other three methods because more than 10% of the calculated differences were outside the limits of agreement. A graphical representation of all method comparisons is shown in Figure …show more content…
All in all, a pronounced degree of analytical variability between the different tests can be detected. The best agreement was found between the LC-MS/MS and the LIAISON CLIA. Although, there are no significant cross-reactions with other steroid hormones in the test according to the manufactures instructions for use, the highest values stated are 0.433% cross-reactivity for each increase to 100 ng/mL testosterone or DHEA, the LIAISON CLIA systematically measures 35% higher values than the LC-MS/MS. Comparisons between LC-MS/MS and RIA as well as between LIAISON CLIA and RIA look similar, but with slightly lower coefficients of correlation. Only the comparison between the Immulite and the other three test formats reveals systematic deviations especially in the higher measuring range that exclude the possibility of interchangeability of the measurement
The lowest coefficients of variation for precision within and between series over the whole tested concentration range were found for the LIAISON CLIA and LC-MS/MS method. Then followed the RIA. The Immulite CLIA showed the highest overall values and thus the lowest precision. A detailed list of all calculated variation coefficients is provided in Table 1 (A).
Sensitivity
The limit of blank (LoB), limit of detection (LoD) and limit of quantification (LoQ) were determined for all methods. The RIA proved to be the most analytically sensitive method, followed by LC-MS/MS. The LIAISON CLIA proved to be less sensitive, the most insensitive method was by far the Immulite CLIA. All determined determination limits are summarized in Table …show more content…
Passing-Bablok regression of the LC-MS/MS versus the LIAISON was y=0.65x-0.01, Pearson`s coefficient of correlation r=0.975 (n=175); LCMSMS versus Immulite was y=0.60x+0.21, r=0.746 (n=125), LC-MS/MS versus RIA was y=0.75x+0.01, r=0.956 (n=80); LIAISON versus Immulite was y=0.96x+0.25, r=0.745 (n=135); LIAISON versus RIA was y=1.17x+0.01, r=0.954 (n=79); and Immulite versus RIA was y=1.29x-0.34, r=0.810 (n=40). All ratios were assumed to be linear. The Immulite CLIA was not interchangeable with the other three methods because more than 10% of the calculated differences were outside the limits of agreement. A graphical representation of all method comparisons is shown in Figure …show more content…
All in all, a pronounced degree of analytical variability between the different tests can be detected. The best agreement was found between the LC-MS/MS and the LIAISON CLIA. Although, there are no significant cross-reactions with other steroid hormones in the test according to the manufactures instructions for use, the highest values stated are 0.433% cross-reactivity for each increase to 100 ng/mL testosterone or DHEA, the LIAISON CLIA systematically measures 35% higher values than the LC-MS/MS. Comparisons between LC-MS/MS and RIA as well as between LIAISON CLIA and RIA look similar, but with slightly lower coefficients of correlation. Only the comparison between the Immulite and the other three test formats reveals systematic deviations especially in the higher measuring range that exclude the possibility of interchangeability of the measurement