Table 2.

Performance of Diagnostic Tests for Congenital Chagas Disease in Specimens from Infants of Infected Mothers

Characteristic	Micromethod						Immunoglobulin M Trypomastigote Excreted-Secreted Antigen–Blot
	Cord Blood		1-Mo Blooda		Cumulative		Cord Blood		1-Mo Blooda		Cumulative
	Neg	Pos	Neg	Pos	Neg	Pos	Neg	Pos	Neg	Pos	Neg	Pos
Infant status
Uninfected	431	0	301	0	445	0	377	2	275	2	399	4
Infected	30	6	20	7	25	13	15	21	14	12	10	28
Performance % [95% CI]
Sensitivity	16.7	[6, 33]	25.9	[11, 46]	34.2	[20, 51]	58.3	[41, 75]	46.2	[27, 67]	73.7	[57, 87]
Specificity	100	[99, 100]	100	[99, 100]	100	[99, 100]	99.5	[98, 100]	99.3	[97, 100]	99.0	[97, 100]
PPV	100	[54, 100]	100	[59, 100]	100	[75,100]	91.3	[72, 99]	85.7	[57, 98]	87.5	[71, 96]
NPV	93.5	[91, 96]	93.8	[91, 96]	94.7	[92, 97]	96.2	[94, 98]	95.2	[92, 97]	97.6	[96, 99]
	Quantitative polymerase chain reaction
	Cord Blood		Umbilical Tissue		1-Mo Blooda		Cumulative
	Neg	Pos	Neg	Pos	Neg	Pos	Neg	Pos
Infant status
Uninfected	390	10	81	1	257	0	411	11
Infected	12	24	11	23	6	19	6	32
Performance % [95% CI]
Sensitivity	66.7	[49, 81]	67.6	[49, 83]	76.0	[55, 91]	84.2	[69, 94]
Specificity	97.5	[95, 99]	98.8	[93, 100]	100	[99, 100]	97.4	[95, 99]
PPV	70.6	[53, 85]	95.8	[79, 100]	100	[82, 100]	74.4	[59, 86]
NPV	97.0	[95, 98]	88.0	[80, 94]	97.7	[95, 99]	98.6	[97, 99]
	Conventional serology at 6 mo or older
	IHA ≥16 at 6 mo		IHA ≥128 at 6 mo		ELISA at 6 mo		IHA ≥16 at 9 mo		ELISA at 9 mo
	Neg	Pos	Neg	Pos	Neg	Pos	Neg	Pos	Neg	Pos
Infant status
Uninfected	203	50	245	8	159	49	166	7	163	3
Infected	1	14	6	9	0	14	0	12	0	12
Performance % [95% CI]
Sensitivity	93.3	[68, 100]	60.0	[32, 84]	100	[77, 100]	100	[74, 100]	100	[74, 100]
Specificity	80.2	[75, 85]	96.8	[94, 99]	76.4	[70, 82]	96.0	[92, 98]	98.2	[95, 100]
PPV	21.9	[13, 34]	52.9	[28, 77]	22.2	[13, 34]	63.2	[38, 84]	80.0	[52, 96]
NPV	99.5	[97, 100]	97.6	[95, 99]	100	[98, 100]	100	[98, 100]	100	[98, 100]

Abbreviations: CI, confidence interval; ELISA, enzyme-linked immunosorbentassay; IHA, indirect hemagglutination assay; NPV, negative predictive value; PPV, positive predictive value.

^aSix infants treated before 1 month of age excluded from 1-month specimen analyses.