Table 1.
Parallel workflow for the IGF1 assay.
Figure 1.
Mass spectra from a normal individual (A) and an individual with a single nucleotide polymorphism (B). m/z values refer to the average mass [M+H]+.
A) Native IGF1 was detected (observed 7649.99 m/z, theoretical 7649.71) along with a putative glycosylated variant (labeled with *; observed 8346.90 m/z, theoretical unknown). B) Both IGF1 (observed 7649.75 m/z, theoretical 7649.71) and IGF1 A67T (observed 7679.75 m/z, theoretical 7679.71) were detected as well as their respective putative glycosylated variants (observed 8349.35 m/z, theoretical unknown and observed 8379.15 m/z, theoretical unknown).
Figure 2.
An example of a standard curve for the IGF1 MSIA.
Plotted are the peak area ratios of IGF1/LR3-IGF1 over the standards concentrations. Solid line: linear fit with R2 = 0.99, SEE = 0.69. Dotted lines: 95% prediction intervals. The average r2 for the twelve standard curves was 0.98 and the range was 0.97–0.99.
Table 2.
Intra-and inter-assay precision.
Table 3.
Assay linearity.
Table 4.
Spiking recovery.
Figure 3.
Histogram of IGF1 concentrations determined by MSIA for 1054 EDTA treated human plasma samples.
Figure 4.
A) Scatter plot. B) Difference plot.