Diagnostic Accuracy of Two Molecular Tools for Diagnosis of Congenital Chagas Disease

Abstract

Background and Objective The real prevalence of congenital Chagas disease is undefined because of difficulties in the detection of Trypanosoma cruzi by microscopic examination. The aim of this study was to determine the diagnostic accuracy of two molecular diagnostic tools, qPCR and LAMP, in the diagnosis of congenital Chagas disease in a clinical setting. Methods To this end, we conducted a prospective cohort study in a tertiary care center, of infants under 9 months of age, born in Buenos Aires to women with Chagas disease. Blood samples were collected for microscopic examination and molecular diagnosis at baseline. If negative, infants were followed up until 9 months of age to determine a final diagnosis by serology. In-house qPCR and LAMP previously validated were challenged as index tests. Results A total of 154 participants were potentially eligible, 120 of whom were enrolled. Finally, 102 (66.2%) of them fulfilled the follow-up. The diagnosis of congenital Chagas disease was confirmed in 13 infants and excluded in 89. Both the sensitivity and specificity of the qPCR were 100.0% (95% confidence interval 75.3–100.0 and 95% confidence interval 95.9–100.0, respectively), whereas the sensitivity and specificity of LAMP were 69.2% (95% confidence interval 38.6–90.9) and 100% (95% confidence interval 95.9–100.0), respectively. Conclusions The qPCR agreed with the current diagnostic algorithm, and was a reliable and sensitive tool to detect congenital Chagas disease earlier, providing an appropriate and timely identification of infected infants requiring treatment. LAMP was able to detect congenital Chagas disease in infected infants by naked-eye visualization in accordance with a microscopic examination. The advantages of molecular diagnostic tools should be taken into account by the health system to improve congenital Chagas disease diagnosis.

Molecular Diagnosis of Chagas Disease: A Systematic Review and Meta-Analysis.

“…The studies also included information on the type of sample collected from the patients (in all cases, these were blood samples) and the number of samples taken. The blood volume taken ranged from 0.5 mL [15,19] to 15 mL [5]; 22 of the 32 (68.7%) studies indicated the preservation conditions of the samples; none reported the time period between sample collection and extraction or performance of the diagnostic tests. A total of 6 studies (18.7%) did not specify the type of ampli cation control of the tests analysed.…”

“…Some individual ndings, such as those of the qPCR method, are more reliable than cPCR for CD diagnosis (Cura et al [19]); the commercial qPCR kit is more e cient in congenital Chagas disease diagnosis (Benatar et al [13]); the kDNA OligoC-TesT showed a signi cantly higher sensitivity than satDNA OligoC-TesT (De Winner et al [20] and Ramírez et al [35]); and the Tc24-based PCR assay is more sensitive than that based on kDNA (Espinoza et al [24]) or TcH2AF/R PCR (Gil et al [26]). In addition, LAMP kits offer appropriate analytical sensitivity for the diagnosis of CD patients and are potentially useful for monitoring treatment response (Besuschio et al, 2017 and2020 [7, 14]); they also offer high performance for the diagnosis of congenital CD (Bisio et al [15], Flores-Chavez et al…”

“…The parasite load of patients was estimated in 12 of the 32 studies analysed (37.5%). Most of the included studies used proprietary methods except for the studies validating commercial LAMP methods [6, 7,14,15,41].…”

“…2 illustrates this increasing trend in journal articles. Regarding study design of the studies included in this review, they are longitudinal comparative studies (some of them multicentre, e.g., Benatar et al [13], or international, e.g., Ramírez et al [35]), some with prospective follow-up, e.g., [13,15,20,22,31,32,36,39,41], and others retrospective (case-control), e.g., [6,7,14,18,19,23,25,30,34]. With respect to Hernández et al…”

“…Of the 32 study papers, 27 papers assessed the diagnostic performance of PCR techniques [5,13,, 3 articles assessed T. cruzi-LAMP technology [6, 7, 14], and two studies evaluated both molecular techniques [15,41]. The characteristics of the included studies are outlined in Table 1 (PCR) and Table 2 (LAMP).…”