Table 1.

Characteristics of the ELISA test kits used. Precision data are from kit brochures (k), collaborative studies reports (l) (Halbmayr-Jech et al., 2015, Immer and Haas-Lauterbach, 2012) or are calculated based on our experiments (e). Different extraction procedures include 1 or 2 steps. RT indicates room temperature, ® – proprietary extraction buffer components undisclosed by the manufacturer, 2-ME – 2-mercaptoethanol, SDS – sodium dodecyl sulphate, PBS – phosphate buffer saline, EtOH – ethanol, mAb – monoclonal antibody, pAb – polyclonal antibody, RSD (relative standard deviation).

			Neogen	AllerTek	Agraquant	Biomedal	Rbiopharm	Transia	Morinaga
Antibody		coating	401.21 (Skeritt) mAb	401.21 (Skeritt) mAb	G12 mAb	A1 mAb	R5 mAb	R5 mAb	anti-wheat protein pAb
		detecting				G12 mAb
		target	HMW-glutenins, ω-gliadins	HMW-glutenins, ω-gliadins	gliadins	gliadins	gliadins	gliadins	wheat protein
Quantification		range	3 – 50	5 – 80	4 – 200	1.56 – 25	5 – 80	1.56 – 25	0.78 – 50
		unit	ppm gluten	ppm gluten	ppm gluten	ng/ml gliadin	ppb gliadin	ng/ml gliadin	ng/ml wheat protein
Calibrant			Gluten(vital wheat gluten extract)	Gluten(in cooked breads)	Gluten(vital wheat gluten extract)	Gliadin	Gliadin	Gliadin	Wheat protein standard
Traceability			Kjeldhal method (N x 6.25)	–	WGPAT gliadin	–	WGPAT gliadin	–	–
Extraction.	Sample to buffer ratio		1:10	1:10	1:40	1:10	1:40	1:40	1:19
	Buffer	1st	®, 40% EtOH	®, 40% EtOH	®	®	®	®	®, 2-ME
		2nd	–	–	80% EtOH	–	40% EtOH	80% EtOH	–
	Time	1st	90 s	15 min	40 min	40 min	40 min	40 min	12 h
		2nd	–	–	1 h	–	1 h	1 h	–
	Temp	1st	RT	45 °C	50 °C	50 °C	50 °C	50 °C	RT
		2nd	–	–	RT	–	RT	RT	–
Repeatability (intra-assay) RSDwa%		12.5–15% (k)	–	16% (l)	–	27% (l)	15% (k)	<10% (k)
Reproducibility (inter-assay) RSDba%		–	–	32% (l)	–	37% (l)	23% (k)	<10% (k)
Repeatability (within-run) RSDwr% (e)		10%	12%	12%	7%	5%	14%	9%
Between-run precision RSDbr% (e)		12%	17%	7%	11%	14%	20%	11%