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. Author manuscript; available in PMC: 2017 Oct 27.
Published in final edited form as: N Engl J Med. 2017 Apr 5;376(17):1647–1658. doi: 10.1056/NEJMoa1611930

Figure 1. GPIHBP1 Immunoassay Interference.

Figure 1

To validate the enzyme-linked immunosorbent assay (ELISA) analysis, recombinant GPIHBP1 was spiked into 40 plasma samples; the results of that analysis are shown here. (Details are provided in Methods Section S2 in the Supplementary Appendix.) Briefly, GPIHBP1 levels in 1:20 dilutions of plasma were measured before and after spiking of the sample with 62.5 pg of recombinant GPIHBP1. In 38 of 40 plasma samples, the mean (±SD) recovery of spiked recombinant GPIHBP1 was nearly complete (98.8±3.8%). In these samples, the mean GPIHBP1 values were 21.0±3.0 pg per milliliter before spiking with recombinant GPIHBP1 and 82.5±3.0 pg per milliliter after spiking. The recovery of recombinant GPIHBP1 in samples obtained from Patients 38 and 101 (two patients with chylomicronemia and low plasma GPIHBP1 levels) was very low (6.8% and 4.4%, respectively). The GPIHBP1 level in the plasma sample obtained from Patient 38 was 3.0 pg per milliliter in the 1:20 dilution and 4.5 pg per milliliter after the sample was spiked; in the sample obtained from Patient 101, the GPIHBP1 levels before and after spiking were 1.0 pg per milliliter and 3.0 pg per milliliter, respectively. Because of the low coefficient of variation in the ELISA analysis, a few of the samples had an apparent recovery rate that was slightly more than 100%.