qPCR Kit Outperforms Microscopy for Early Detection of Congenital Chagas Disease
A prospective multicenter study across endemic and non-endemic sites in Argentina evaluated a duplex TaqMan qPCR kit for early diagnosis of congenital Chagas disease in 370 infants. The qPCR demonstrated higher sensitivity (72.7%) and specificity (99.2%) in peripheral venous blood compared to the standard micromethod (AUC 0.86 vs 0.68), while also enabling parasite load quantification and strain typing. This first prospective field validation supports qPCR as an auxiliary tool to improve detection of the 3.8% congenital transmission rate.
The original study
Prospective multicenter evaluation of real time PCR Kit prototype for early diagnosis of congenital Chagas disease.
- Authors
- Benatar AF, Danesi E, Besuschio SA, Bortolotti S, Cafferata ML, Ramirez JC, et al.
- Journal
- EBioMedicine
- Type
- Evaluation Study, Journal Article, Multicenter Study
- PMID
- 34186488
Original abstract
BACKGROUND: Current algorithm for Congenital Chagas Disease (cCD) diagnosis is unsatisfactory due to low sensitivity of the parasitological methods. Moreover, loss to follow-up precludes final serodiagnosis after nine months of life in many cases. A duplex TaqMan qPCR kit for Trypanosoma cruzi DNA amplification was prospectively evaluated in umbilical cord (UCB) and peripheral venous blood (PVB) of infants born to CD mothers at endemic and non-endemic sites of Argentina. METHODS: We enrolled and followed-up 370 infants; qPCR was compared to gold-standard cCD diagnosis following studies of diagnostic accuracy guidelines. FINDINGS: Fourteen infants (3·78%) had cCD. The qPCR sensitivity and specificity were higher in PVB (72·73%, 99·15% respectively) than in UCB (66·67%, 96·3%). Positive and negative predictive values were 80 and 98·73% and 50 and 98·11% for PVB and UCB, respectively. The Areas under the Curve (AUC) of ROC analysis for qPCR and micromethod (MM) were 0·81 and 0·67 in UCB and 0·86 and 0·68 in PVB, respectively. Parasitic loads ranged from 37·5 to 23,709 parasite equivalents/mL. Discrete typing Unit Tc V was identified in five cCD patients and in six other cCD cases no distinction among Tc II, Tc V or Tc VI was achieved. INTERPRETATION: This first prospective field study demonstrated that qPCR was more sensitive than MM for early cCD detection and more accurate in PVB than in UCB. Its use, as an auxiliary diagnostic tool to MM will provide more accurate records on cCD incidence. FUNDING: FITS SALUD 001-CHAGAS (FONARSEC, MINCyT, Argentina) to the Public-Private Consortium (INGEBI-CONICET, INP-ANLIS MALBRAN and Wiener Laboratories); ERANET-LAC-HD 328 to AGS and PICT 2015-0074 (FONCYT, MinCyT) to AGS and FA.