TABLE 9.

Illustrative effect of European immunoblot interpretation rules on percent sensitivity and specificity^a

Ruleb	No. of bands	Average		Laboratory A		Laboratory B		Laboratory C		Laboratory D (B. afzelii)		Laboratory D (B. garinii)		Laboratory E (no IgM OspC)		Laboratory F
		% Sensc	% Specd	% Sens	% Spec	% Sens	% Spec	% Sens	% Spec	% Sens	% Spec	% Sens	% Spec	% Sens	% Spec	% Sens	% Spec
1	2	68	91	85	92	59	95	73	78	55	99	53	99	81	91	73	80
	3	29	100	45	100	25	100	33	99	19	100	11	100	34	99	38	99
2	2	75	89	85	92	81	94	73	78	61	98	57	99	88	85	82	79
	3	49	98	54	99	53	99	41	99	43	99	37	100	64	97	50	97
3	2	87	72	92	73	87	88	96	44	75	92	72	89	95	70	95	47
	3	69	92	76	95	66	98	71	82	57	99	50	99	84	91	81	80
4	2	77	88	86	89	81	94	74	76	67	97	57	99	89	84	82	79
	3	56	98	66	99	56	99	47	99	54	99	40	100	67	97	56	97
5	2	87	72	93	71	88	88	96	46	80	92	74	89	95	69	95	47
	3	71	92	80	94	67	98	73	81	62	98	51	99	85	91	81	80
6	2	79	86	86	87	85	92	78	76	68	97	57	99	89	84	88	67
	3	62	96	73	95	60	99	56	99	56	99	42	100	68	96	78	87
7	2	90	70	93	69	91	86	96	44	83	92	74	89	95	69	97	39
	3	74	90	82	92	69	98	77	81	62	98	57	99	85	91	88	69
	4	58	97	69	97	49	99	55	99	54	99	38	100	66	97	77	87

^aExamples of the “best” qualifying rules (70% sensitivity and 90% specificity) for each laboratory are given in boldface italic type. 

^bRules 1 and 3 were eliminated because they did not provide an adequate combination of sensitivity and specificity for all laboratories. 

^cSens, sensitivity was calculated by combining data for IgG and IgM. 

^dSpec, specificity was calculated by combining data for potential cross-reactor and healthy individuals' sera.