Table 1.

Results of HIV testing in three U.S. State Public Health Laboratories.

	Massachusetts State Public Health Laboratory, Boston MA	Michigan State Public Health Laboratory, Lansing MI	Maryland State Public Health Laboratory, Baltimore MD
Results of fourth-generation immunoassay screening	Bio-Rad GS HIV Antigen/Antibody Combo	Bio-Rad GS HIV Antigen/Antibody Combo	Abbott Architect HIV Antigen/Antibody Combo
Prospective time period	July 1, 2012-June 30, 2013	November 27, 2012-June 30, 2013	July 1, 2012-June 30, 2013
Immunoassay test results
Total	7914	6069	36266
Non-reactive	7652 (96.69%)	5898 (97.18%)	35232 (97.15%)
Repeatedly reactive	262	171	1034
Results of supplemental testing in specimens with repeatedly reactive results
Confirmed HIV-1 antibody positivea	246 (3.11%)	163 (2.68%)	983 (2.71%)
Acute infectionb	8 (0.10%)	1 (0.02%)	19 (0.05%)
IA false positivec	7 (0.09%)	5 (0.08%)	29 (0.08%)
HIV-2 positived	1 (0.01%)	0 (0.00%)	1 (0.003%)
Other	0 (0.00%)	2 (0.03%)e	2 (0.005%)f
Specificity of the fourth-generation immunoassay	99.9%	99.9%	99.9%

^aHIV-1 positive by Western blot (WB) or supplemental HIV-1/HIV-2 antibody test

^b4^th generation immunoassay (IA) reactive, WB or HIV-1/HIV-2 differentiation IA negative or indeterminate, reactive nucleic acid test (NAT)

^c4^th generation IA reactive, WB or HIV-1/HIV-2 differentiation IA negative or indeterminate, NAT not reactive

^dPositive for HIV-2 by HIV-1/HIV-2 differentiation IA or HIV-2 WB or differential HIV-1/HIV-2 proviral DNA conventional polymerase chain reaction

^eIA reactive, HIV-1/HIV-2 differentiation IA undifferentiated, WB positive, NAT not reactive (n=1); IA reactive, HIV-1/HIV-2 differentiation IA undifferentiated, NAT not reactive (n=1)

^fIA reactive, WB indeterminate, HIV-1/HIV-2 differentiation IA positive, NAT not reactive (n=1); IA reactive, WB indeterminate, HIV-1/HIV-2 differentiation IA negative, NAT not reactive (n=1)