Table 1 - Choice of the adequate quantification method for recombinant human GM-CSF produced in different host systems

Table 1.

Comparison of different assays to quantify rhGM-CSF. To measure intra-assay variation, the samples were assayed as triplicates. To assess inter-assay reproducibility, we analysed the same samples of rhGM‑CSF on three occasions.

	Sandwich ELISA (2 MAbs)	Sandwich ELISA (MAb-PAb)	Competitive ELISA	Cell Proliferation Assay
Linear range (ng/ml) r > 0.99	0.39 - 6.25	0.78 - 200	3.125 - 25.0	0.009 - 2.250 (0.1 - 25.0 U/ml)
Detection limit (pg/ml)	100	780	780	9
Mean recovery (%)^a	83.9 ± 2.3	112.4 ± 8.6	82.0 ± 4.2	-
Intra-assay CV (%)^b	8.7	5.6	15.7	28.4
Inter-assay CV (%)^c	5.5	9.8	14.4	14.6

^a Mean standard error of the mean, SEM, at the middle of the linear range.
^bMean intra-assay CV (standard deviation / mean concentration x 100) for all dilutions.
^c Mean inter-assay CV (standard deviation / mean concentration x 100) for all dilutions.