Table 1.

Cases of Congenital Chagas Disease Determined Using the Composite Reference Standard in the Training and Validation Cohort

Group and Age	Composite Reference Standard	Training Cohort	Validation Cohort
Early diagnosis
0 mo, No.	Positive microscopy	6a	19a
	Positive qPCR and IgM-TESA blot	10	12
0 and/or 1 mo, No.	Positive microscopy	3b	1c
	Positive qPCR at 0 and 1 mo	3	1
	Positive qPCR and IgM-TESA blot at 1 mo	2	2
	Positive qPCR at 0 mo and IgM-TESA blot at 1 mo	1	0
	Positive IgM-TESA blot × 2	1	0
Total, no./No. (%)	…	26/34 (76.5)	35/43 (81.3)
Late diagnosis	…
6–9 mo, no./No. (%)	Positive by 2 IgG tests	8/34 (23.5)	8/43 (18.6)
Total (early and late diagnosis), No.	…	34	43

Neonates were considered to have congenital Chagas disease (CChD) at birth if the result of microscopy was positive and/or the results of qPCR and IgM-TESA blot were positive. Neonates were considered to have CChD at 1 month if (1) microscopy at 1 month was positive; (2) qPCR and IgM-TESA blot were positive at age 1 month; (3) qPCR (or IgM-TESA blot) was positive at 0 month and IgM-TESA blot (or qPCR) was positive at age 1 month; (4) they had 2 positive results by qPCR at different times (0 and 1 month of age); or (5) had 2 positive results by IgM-TESA blot at different times (0 and 1 month of age). Cases were assigned based on the earliest criterion of diagnosis.

Abbreviations: IgG, immunoglobulin G; IgM-TESA blot, Western blot with trypomastigote excretory-secretory antigen for the detection of immunoglobulin M antibodies; qPCR, quantitative polymerase chain reaction.

^aAll neonates in these cells were also positive by qPCR and IgM-TESA blot at birth.

^bTwo of these infants were positive by qPCR at birth and 1 month, and 1 was positive by qPCR at birth and to IgM-TESA blot at 1 month.

^cThe sample was also positive by qPCR at 0 and 1 month.