TABLE 2.

Qualitative evaluation results of the IgG anti-PT ELISA test during an interlaboratory collaborative study^a

Sample identifier	Mean sample concentrations (EU/ml)b	No. of resultsc	% of determinations scored as:
			Negative (ODS < ODCII)	Intermediate (ODS ≥ ODCII and < ODCIII)	Positive (ODS ≥ ODCIII)
S1	< 15	39	100	0	0
S2	32	32	91	9	0
S3	53	104	42	54	4
S4	74	99	3	71	26
S5	100	34	0	26	74
S6	109	34	3	21	76
S7	148	97	0	0	100
S8	230	93	1	0	99

^aThe OD of samples (OD_S) were compared with the OD of controls CII and CIII (OD_CII and OD_CIII, respectively). Boldface (samples S3 and S4) indicates those samples with an IgG anti-PT concentration between those of CII (49 EU/ml) and CIII (94 EU/ml).

^bELISA units/ml.

^cAll results from valid plates were used provided that the %CV criteria were met for CII, CIII, and sample. Qualitative analyses were based solely on ODs; no results were excluded based on calculated values of <15 EU/ml or >480 EU/ml.