Table 1.

Antigens included in multiplex bead assay

Antigen	Organism	Cutoff method*	Cutoff
pgp36	Chlamydia trachomatis	ROC†	1,113
CT6946	Chlamydia trachomatis	ROC†	337
CTBc	Vibrio cholera
ETEC LTB‡	Heat labile toxin-producing enterotoxigenic Escherichia coli
Cp1711	Cryptosporidium parvum	Standard curve§	182
Cp2311	Cryptosporidium parvum	Standard curve§	323
LecA12	Entamoeba histolytica	Mean +3 SD‖	28
p1813	Camplyobacter jejuni
p3913	Camplyobacter jejuni
Sal Bc	Salmonella typhimurium Group B
Sal Dc	Salmonella enteritidis Group D
VSP314	Giardia lamblia	Mean +3 SD‖	167
VSP514	Giardia lamblia	Mean +3 SD‖	295

^*Blank cells indicate that the antibody response was not classified as seropositive or seronegative.

^†Receiver operating characteristics (ROC) curve derived from a panel of external standards that were previously classified as positive or negative by MBA, using Youden’s index to determine threshold.⁷

^‡Sigma Chemical Co., St. Louis, MO.

^§Threshold defined using a 2-fold serial dilution curve with previously established unit cutoff values.⁸

^‖The third standard deviation above the mean from a sample of 86 volunteers from the CDC who did not travel internationally.