Fig. 2.

Anti-Bovine ALP Ab Spiking Studies. A, Human serum spiked with 1.7 ng/ml E2 and 3.4 ng/mL uE3 was incubated in the presence or absence of different concentrations of anti-calf intestinal ALP Abs – sheep polyclonal ALP Ab (#367321; A, D), mouse monoclonal ALP Ab (#P4071-15; B, E), and mouse monoclonal ALP Ab (#MIA1703; C, F). Serial dilutions were performed and specimens were tested for E2 (A-C) and uE3 (D-F) on DxI 800 instruments. Dashed lines indicate RLU thresholds for the assay upper calibrator (A-F), whereas dotted lines indicate the RLU threshold for the assay zero calibrator (only visible in D; RLU, 1080727). *, p ​< ​0.05 compared to measurement in the absence of spiked antibody. Note that as a competitive immunoassay, increased RLUs correlate to decreased apparent analyte concentrations.