Variability of anti-human transglutaminase testing in celiac disease across Mediterranean countries

Table 1 TGA assay kits used by each centre

Centre	Kit (Manufacturer)	Cut-off
Naples	Anti-Tissue Transglutaminase IgA (Delta Biologicals)	7 U/mL
Spain	Elia Celikey IgA (Phadia, Thermofisher)	7 U/mL
Messina	Transglutaminasi Umana IgA	3 U/mL
	(IPR - Immuno Pharmacology Research s.r.l)
Albania	Celiac Ttg IgA (Immco Diagnostic, Hague Netherlands)	25 EU/mL
Slovenia	Eu-Ttg IgA (Eurospital)	16 U/mL
Tunisia	Quanta Lite® R H-Ttg Elisa (Inova Diagnostics)	10 U/mL
Turkey	Anti-Tissue Transglutaminase IgA (Orgentec)	10 U/mL
Greece	Quanta Lite® H-Ttg Elisa (Inova Diagnostics)	20 U/mL

Table 2 Mean results from each Centre by the expected value

Expected values	1	3	10	20	50	60	100
Naples	0.23	0.76	10.67	19.50	48.99	59.66	91.12
Spain	0.16	0.69	7.73	16.32	34.13	62.13	67.73
Messina	1.60	1.97	3.04	21.17	57.87	52.75	95.25
Albania	0.77	1.01	6.22	15.25	44.27	44.12	62.61
Slovenia	0.10	0.70	8.10	16.73	44.30	41.33	89.2
Greece	0.83	1.76	14.13	25.97	56.99	89.12	86.05
Tunisia	0.16	0.16	4.48	10.56	31.68	36.69	64.85
Turkey	0.21	0.53	5.76	11.89	28.27	37.12	47.09
MEAN	0.51	0.95	7.52	17.17	43.31	52.87	75.49
SD	0.53	0.62	3.55	5.00	11.21	17.59	17.24