Diagnostic study on an immunochromatographic rapid test for schistosomiasis: comparison between use on serum and on blood spot from fingerprick

Abstract

BackgroundAn immunochromatographic rapid test (ICT; Schistosoma ICT IgG-IgM, LDBIO Diagnostics) demonstrated high sensitivity (96%) in the diagnosis of Schistosoma mansoni and S. haematobium. To date, the test has been validated for use on serum only, but in the absence of lab equipment, blood drop from fingerprick could be a useful option. This method is acquiring more interest because of the high flow of migrants rapidly moving across Italy and other European countries.ObjectiveThe aim of this prospective study was to evaluate the use of ICT on whole blood obtained from fingerprick.SettingCentre for Tropical Diseases (CTD), Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy.ParticipantsThe inclusion criteria were African migrants aged ≥18 years with epidemiological risk of infection. The exclusion criteria were refusal to participate in the study and impossibility of execution of one of the two study methods, for any reason. Seventy of the 72 eligible patients completed the study, 79% of whom were male.InterventionsThe ICT was performed twice for each included patient: one on blood drop (by the research nurses, in the ward) and one on serum (by staff of CTD lab). The primary outcome was the concordance between the two methods, assessed by Cohen’s kappa.ResultsCohen’s kappa was 0.45 (95% CI 27.0 to 63.6), indicating moderate agreement between the ICT on serum and the ICT on blood drop. Assuming the results on serum as reference standard for diagnosis, the sensitivity and specificity of ICT on blood drop were 55% (95% CI 40 to 69) and 93% (95% CI 79 to 98), respectively.ConclusionsThe agreement between the two diagnostic methods is too low to support the alternative one. Implementation of the kit for using blood drop instead of the serum and/or further studies aimed to identify easy-to-use tests for schistosomiasis feasible outside referral centres for tropical diseases are needed.

Diagnostic accuracy of Schistoso ma ICT Ig G - IgM and comparison to other used techniques screening urinary schistosomiasis in Nigeria

“…The use of Schistosoma ICT IgG-IgM will avoid the misconfidence and untrust of rural inhabitants towards the laboratory examination of schistosomiasis in Primary Health Cares. Schistosoma ICT IgG-IgM had a similar report as it was used to screen illegal Africans that resided on sea lands in Italy when they were migrating to various European countries [15,16]. Proteinuria had the second higher concordance, this could be the effect of S. haematobium eggs on the glomeruli leading to excretion of albumin in urine thereby indicating infection with urinary schistosomiasis.…”

Schistosomiasis Among Female Migrants in Non-endemic Countries: Neglected Among the Neglected? A Pilot Study

“…Exposure to schistosomiasis was confirmed using the standard ELISA SCHISTO-96 serological test (SciMedx Corporation, Denville, NJ, USA) on a blood serum extracted from participants. Cross-check examination of urine and stool samples was not performed since it did not add substantial benefit to the screening strategy due to the very low yield ( 3 , 4 ). Proportions were calculated considering as a denominator participants with corresponding data available and stratified by serology results, as shown in Table 1 .…”

“…Estimation of the real burden of schistosomiasis is hampered by the lack of an adequate gold standard for diagnosis. Detection of parasite eggs in urine or stool samples has very low sensitivity and serological testing is considered the most cost-effective diagnostic tool in non-endemic countries (3)(4)(5).…”

Schistosomiasis screening in non-endemic countries from a cost perspective: Knowledge gaps and research priorities. The case of African long-term residents in a Metropolitan Area, Spain

“…Future research should also focus on the development of point-of-care (POC) tests (e.g. a finger-prick blood test) [52] that would help to effectively implement a rapid test-and-treat strategy, and the development of more specific diagnostic methods in order to avoid unnecessary treatment (e.g. a PCR-based diagnostic that could differentiate among Schistosoma species, for clinical and/or laboratory use) to overcome the limitations of the serology test (including false-negative results).…”