Adaptation of alpha-fetoprotein and intact human chorionic gonadotropin fluoroimmunometric assays to dried blood spots

Neto, Eduardo Vieira; Carvalho, Eulália C.D.; Fonseca, Armando A.

doi:10.1016/j.cccn.2005.04.023

Cited by 7 publications

(4 citation statements)

References 6 publications

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“…Yet, this scenario cannot be imaged in the developing countries, where contemporary prenatal care is restrained by limited medical personnel and substantial supplies. In the current study, we first focused on validation of DBS method accompanied by time-resolved immunofluorescence analysis, 18 which can be affordably applied in the medically disadvantaged areas, such as rural China.…”

Section: Discussionmentioning

confidence: 99%

“…Numerous previous reports have examined the similarity and difference between DBS and MMS on their efficiency in assaying serum proteins, but most of the studies concentrated on the assay per se 18 to compare the assay’s validity represented by intra- and inter-assay variability between two sampling methods. Almost all studies 18 agreed upon those analysts, such as AFP and HCG assayed from DBS samples, correlated well with the results produced by conventional serum assay. In addition, most assays examined retrospective blood samples 25 in contrast to our prospective clinical trial with advanced careful and matched experimental designs.…”

Section: Discussionmentioning

confidence: 99%

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A prospective clinical trial to compare the performance of dried blood spots prenatal screening for Down’s syndrome with conventional non-invasive testing technology

Jiang

Zhang

et al. 2017

Exp Biol Med (Maywood)

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Children born with Down's syndrome display a wide range of mental and physical disability. Currently, there is no effective treatment to ease the burden and anxiety of the Down's syndrome family and the surrounding society. This study is to evaluate the efficiency of dried blood spots against serum screening for Down's syndrome and to construct a two-tier strategy by topping up the fetal cell-free DNA (cfDNA) secondary screening over the high-risk women marked by the primary blood testing to build a practical screening tactic to identify fetal Down's syndrome. Results demonstrate that fetal cfDNA can significantly reduce false-positive rate close to none while distinguishing all true positives. Thus, we recommend that fetal cfDNA analysis to be utilized as a secondary screening tool atop of the primary blood protein screening to further minimize the capacity of undesirable invasive diagnostic operations. AbstractTo evaluate, side by side, the efficiency of dried blood spots (DBSs) against serum screening for Down's syndrome, and then, to construct a two-tier strategy by topping up the fetal cellfree DNA (cfDNA) secondary screening over the high-risk women marked by the primary blood testing to build a practical screening tactic to identify fetal Down's syndrome. One thousand eight hundred and thirty-seven low-risk Chinese women, with singleton pregnancy, were enrolled for the study. Alpha-fetoprotein and free beta human chorionic gonadotropin were measured for the serum as well as for the parallel DBS samples. Partial high-risk pregnant women identified by primary blood testing (n ¼ 38) were also subject to the secondary cfDNA screening. Diagnostic amniocentesis was utilized to confirm the screening results. The true positive rate for Down's syndrome detection was 100% for both blood screening methods; however, the false-positive rate was 3.0% for DBS and 4.0% for serum screening, respectively. DBS correlated well with serum screening on Down's syndrome detection. Three out of 38 primary high-risk women displayed chromosomal abnormalities by cfDNA analysis, which were confirmed by amniocentesis. Either the true detection rate or the false-positive rate for Down's syndrome between DBS and the serum test is comparable. In addition, blood primary screening aligned with secondary cfDNA analysis, a ''before and after'' two-tier screening strategy, can massively decrease the false-positive rate, which, then, dramatically reduces the demand for invasive diagnostic operation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

A prospective clinical trial to compare the performance of dried blood spots prenatal screening for Down’s syndrome with conventional non-invasive testing technology

Jiang

Zhang

et al. 2017

Exp Biol Med (Maywood)

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“…18 More recently, immunofluorometric ␣-fetoprotein and intact hCG assays have been adapted for measurement of these analytes in dried blood spots for the purposes of prenatal screening for neural tube defects and Down syndrome. 19 Once the feasibility of measurement of prenatal screening markers using dried blood spots has been demonstrated, the next step is to conduct intervention studies to gain information on screening performance in practice. A number of these have been published, and in general the screening performance using dried blood spots has been comparable to that reported for serum.…”

Section: Discussionmentioning

confidence: 99%

Estimating first-trimester combined screening performance for Down syndrome in dried blood spots versus fresh sera

Palomaki

Neveux

Knight

et al. 2007

Genetics in Medicine

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Purpose: The study purpose was to examine the consequences of using dried blood spots rather than fresh sera in first-trimester Down syndrome screening. Methods: We collected and compared human chorionic gonadotropin and pregnancy-associated plasma protein-A results from clients providing dried blood spots (Cohort 1) and from other clients providing fresh sera (Cohort 2). Inclusion and exclusion criteria aimed at ensuring the two cohorts were similar. Results: The average concentrations of human chorionic gonadotropin and pregnancy-associated plasma protein-A are significantly different for the two cohorts. When the results are converted to multiples of the median and weight-adjusted, the variances for human chorionic gonadotropin and pregnancy-associated plasma protein-A in Cohort 1 are greater by 25% and 14%, respectively. Modeling the impact of this increased variance shows that Down syndrome detection is expected to be lower in Cohort 1 (83% vs. 85% at a 5% false-positive rate) or the false-positive rate is expected to be higher (3.9% vs. 3.0% at an 80% detection rate). Conclusions: This study of two closely matched cohorts provides indirect evidence that dried blood spots will result in slightly lower Down syndrome screening performance. Studies should be undertaken to confirm and further quantify differences in assigned risks by a direct comparison using matched serum and dried blood spots collected from the same Virtually all prenatal screening protocols for Down syndrome use measurements made in maternal serum, sometimes with the inclusion of first-trimester ultrasound determination of nuchal translucency (NT) thickness. In a few reports, these serum markers have been measured by using dried blood spots rather than fresh sera. 1-4 Collection of blood spots is less invasive than drawing blood and is sometimes more convenient for office personnel and the patient because referral to a phlebotomy station is not required. Also, some analytes can be more stable in blood spots than in whole blood or serum when shipping and handling occurs under conditions such as elevated temperature (e.g., the free ␤-subunit of human chorionic gonadotropin [hCG]). 5 There is limited information concerning possible differences introduced by the choice of sample type. To our knowledge, no study has made a direct (matched) comparison of the screening performance of maternal Down syndrome markers using measurements obtained from a dried blood spot and maternal serum collected from the same women. Matched studies have been undertaken for other analytes, such as newborn screening markers 6 and prostate-specific antigen. 7 Although not as powerful as a matched study, a cohort study design can yield information on the relative performance of the two sample types when results are compared from women screened who provided blood spots with those screened who provided maternal serum. The current study was undertaken to determine whether any meaningful differences attributable to collection method are observed between two similar cohorts o...

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“…This approach has already been attempted in other situations: as a second tier test for tyrosinemia newborn screening (26), as a screening for fetal neural tube defects and trisomy 21 in pregnancy (27)(28)(29), and for liver adenocarcinoma mass screening in adults (30). In this study, we adapted the method for αFP plasmatic measurement to blood dried on standard newborn screening filter paper and studied its reliability by comparing it with the traditional method, in both blood of patients with hepatoblastoma predisposition syndromes and controls.…”

Section: Discussionmentioning

confidence: 99%

α-Fetoprotein assay on dried blood spot for hepatoblastoma screening in children with overgrowth-cancer predisposition syndromes

Mussa

Pagliardini

et al. 2014

Pediatr Res

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Background: Beckwith-Wiedemann syndrome (BWS) and hemihyperplasia (HH) are overgrowth conditions with predisposition to hepatoblastoma for which early diagnosis patients undergo cancer screening based on determination of the tumor marker α-fetoprotein (αFP). Repeated blood draws are a burden for patients with consequent compliance issues and poor adherence to surveillance protocol. We sought to analyze feasibility and reliability of αFP dosage using an analytical micromethod based on blood dried on filter paper (DBS). Methods: Overall 143 coupled αFP determinations on plasma and DBS collected simultaneously were performed, of which 31 were in patients with hepatoblastoma predisposition syndromes and 112 were in controls. The plasma αFP dosage method was adapted to DBS adsorbed on paper matrix for newborn screening. results: There was strong correlation between plasmatic and DBS αFP (r 2 = 0.999, P < 0.001). Cohen's k coefficient for correlation was 0.96 for diagnostic cut-off of 10 U/ml (P < 0.001), commonly employed in clinical practice. The measurements on plasma and DBS were highly overlapping and consistent. conclusion: The DBS method allowed to dose αFP reliably and consistently for the concentrations commonly employed in clinical settings for the screening of hepatoblastoma, opening new scenarios about conducting cancer screening in overgrowth syndromes.

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Adaptation of alpha-fetoprotein and intact human chorionic gonadotropin fluoroimmunometric assays to dried blood spots

Cited by 7 publications

References 6 publications

A prospective clinical trial to compare the performance of dried blood spots prenatal screening for Down’s syndrome with conventional non-invasive testing technology

A prospective clinical trial to compare the performance of dried blood spots prenatal screening for Down’s syndrome with conventional non-invasive testing technology

Estimating first-trimester combined screening performance for Down syndrome in dried blood spots versus fresh sera

α-Fetoprotein assay on dried blood spot for hepatoblastoma screening in children with overgrowth-cancer predisposition syndromes

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