Table 1. Calculated volumes of blow required per well to reach 50%B/Bo (the middle of the standard curve) for each cortisol EIA tested.

Assay Kit	Vol of unknown required per well (µl)	Dilution for 50% B/Bo	Actual Vol. of sample needed per well (µl)
Cayman	50	1∶4 to 1∶16	3.125–12.5
Arbor Assays	50	1∶2	25
MP Biomedical	25	ND	ND
ENZO	100	1 to 1∶2	50–100
Salimetrics	25	1	25

MP biomedical did not provide measurements necessary to calculate the %B/Bo and so absorbance values were used during assessment (indicated by ND  =  no data).