Recovery of Anti-
            <i>Toxoplasma gondii</i>
            Immunoglobulin M in Stored Guthrie Card Blood Spots

Tan, H Van; Petersen, Eskild; Møller, Line; Phillips, Pamela; Neto, Eurico Camargo; Gilbert, Ruth

doi:10.1128/jcm.00893-09

Cited by 6 publications

(10 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This situation is mainly observed in countries where maternal screening is not performed (29). Thus, the possibility of testing stored Guthrie cards could be helpful in distinguishing acquired from congenital toxoplasmosis (1,15,22).…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, it should be emphasized that the retrospective use of DBS specimens for diagnosis of different congenital infections has raised questions regarding the stability of nucleic acids and antibodies on filter paper (15,31), as well as the sensitivity of DNA recovery methods and amplification techniques (32,(34)(35)(36).…”

Section: Discussionmentioning

confidence: 99%

“…At present, only a few studies have evaluated the usefulness of DBS testing for retrospective CT diagnosis and investigated the recovery of specific IgM to distinguish between congenital and acquired toxoplasmosis in children presenting with symptoms later in childhood (15) or the clinical usefulness of the measurement of T. gondii IgG avidity on DBS specimens in the postnatal diagnosis of congenital toxoplasmosis (22).…”

mentioning

confidence: 99%

“…In any case, it is noteworthy that only conventional automated assays have been used for CT diagnosis with DBS specimens (10,15,(19)(20)(21), while, curiously, no study has been designed to evaluate WB performance with eluted DBS samples. Moreover, detection of T. gondii DNA has never been attempted on DBS samples, even as a control for other congenital infectious diseases, such as those caused by cytomegalovirus or rubella.…”

mentioning

confidence: 99%

“…In particular, preprinted collection cards known as Guthrie cards have been designed for mass screening for inborn errors of metabolism (9). In the last 2 decades, many studies focused their attention on the usefulness of DBS card analysis as an alternative method to diagnose and monitor several congenital infectious diseases (10) or as a viable option for surveillance in settings where the collection of serum samples remains challenging (11,12), since it allows the evaluation of specific antibody levels (13)(14)(15) as well as the presence of nucleic acids (16)(17)(18).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Evaluation of a New Protocol for Retrospective Diagnosis of Congenital Toxoplasmosis by Use of Guthrie Cards

et al. 2014

View full text Add to dashboard Cite

The aim of this study was to assess the diagnostic value of IgM Western blotting (WB), IgA enzyme immunoassay (EIA), and DNA amplification by real-time PCR on Guthrie cards to retrospectively establish the diagnosis of congenital toxoplasmosis (CT). To this purpose, Guthrie cards were collected from 18 infants born to mothers with primary Toxoplasma gondii infection during pregnancy. Moreover, the analytical sensitivity of T. gondii PCR was assessed by testing mock dried blood specimens set up with several known DNA dilutions. IgM WB was demonstrated to be the most sensitive method. When the results of T. gondii DNA detection and specific IgM recovery were combined, retrospective CT diagnosis by using Guthrie cards was established in 3 out of 6 infected infants (sensitivity, 50%; 95% confidence interval, 26.8% to 73.2%). No positive PCR or serologic results were found in the group of 12 uninfected infants, demonstrating the excellent specificity of the three methods (95% confidence interval, 78.1% to 99.5%). The findings of the present study suggest that, in cases of missed diagnosis of CT at birth, analysis of Guthrie cards for children with compatible clinical findings after the perinatal period, in particular the combination of recovery of specific IgM antibodies and T. gondii DNA amplification, could be helpful. Nevertheless, since suboptimal conditions of storage of dried blood specimens can seriously affect sensitivity, negative results cannot rule out CT diagnosis. In contrast, because of the excellent specificity shown by IgM serologic testing and T. gondii DNA amplification on Guthrie cards, positive results obtained by either of the two methods should be considered diagnostic.

show abstract