Figure 6

Biases introduced by location artifacts in the commercial CAT instrument. A. Plate layout demonstrating two locations of calibrations curves, column 1 vs. averaged symmetrical columns 1 + 12, used for bioassay analysis in this figure. “TC” denotes thrombin calibrator wells. B. Calibration curves from column 1 (filled symbols) and averaged columns 1 + 12 (open symbols) fitted using polynomial equations (red lines). Means ± S.D. (n = 2 wells). C. Calculated FXIa concentrations obtained for either individual columns 1 through 12 against calibration curve from column 1 (filled symbols) or for averaged symmetrical columns 1 + 12, 2 + 11, etc. against the calibration curve from columns 1 + 12. The activities of FXIa samples were calculated under the assumption that each column contained a single sample that was serially diluted, starting with the highest “neat” sample in the first well of the respective column, followed with 2.5 dilutions for wells 2 through 7 (well 8 was “blank” buffer control). In the bioassay, TPH of each well in the column series was compared with the calibration curve (Figure 6B), and resultant FXIa concentration was multiplied by the respective dilution factor. Thereafter, the FXIa data from the first 6 wells were averaged, and S.D. was calculated. The highest diluted sample in well 7 was ignored because it was too close to the limit of assay detection.