Table 5.

Negative predictive value (%) for three pairs of tests according to the parallel and serial testing schemes as well as epidemiological variables for donors with inconclusive serology screening

	Parallel						Serial
	ELISA/c-ELISA		ELISA/rec-ELISA		c-ELISA/rec-ELISA		ELISA/c-ELISA		ELISA/rec-ELISA		c-ELISA/rec-ELISA
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
General	99.98	0.03	99.98	0.02	99.98	0.02	98.36	1.11	98.42	1.01	98.38	1.06
First time donor	99.99	0.01	99.99	0.01	99.99	0.02	99.41	0.55	99.42	0.56	99.40	0.58
Repeat donor	99.99	0.06	99.99	0.03	100	0.03	98.86	1.99	98.93	1.75	98.95	1.73
Age < 30 years	99.63	0.58	99.67	0.43	99.66	0.45	89.82	5.67	90.17	5.42	90.01	5.45
Age > 30 years	100	0.00	100	0.00	100	0.00	99.82	0.23	99.82	0.22	99.81	0.25
Male	99.96	0.09	99.96	0.05	99.96	0.05	96.93	2.24	97.07	2.00	97.04	2.08
Female	100	0.00	100	0.00	100	0.00	99.84	0.18	99.84	0.20	99.83	0.20
Endemic region
No	99.93	0.10	99.94	0.08	99.94	0.08	97.11	1.70	97.19	1.65	97.20	1.50
Yes	99.99	0.03	99.99	0.02	99.99	0.02	98.67	1.16	98.72	1.04	98.67	1.14
Contact with vector
No	99.96	0.09	99.96	0.06	99.96	0.06	96.86	2.54	96.95	2.32	96.88	2.43
Yes	100	0.00	100	0.00	100	0.00	99.82	0.19	99.83	0.18	99.82	0.19
Family history
No	99.90	0.15	99.91	0.12	99.90	0.12	93.80	3.55	94.00	3.44	93.91	3.40
Yes	100	0.01	100	0.00	100	0.00	99.77	0.33	99.78	0.27	99.77	0.33

SD: Standard Deviation