Biochemical screening

Evans, Mark I.; OʼBrient, Joseph E.; Dvorin, Elena; Johnson, Mark P.

doi:10.1097/00001703-199410000-00011

Cited by 13 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The concept of considering NT measurements to be merely another lab analyte value when used in an algorithm has required a major culture adjustment to those who considered ultrasound to be an 'art' rather than a lab value [12] . As United States National Institute for Child Health and Human Development funded studies such as BUN and FASTER trials have confirmed the efficacy of first-trimester screening, there has been a rapid expansion of utilization of screening in the United States [13,14] .…”

Section: Introductionmentioning

confidence: 99%

Nuchal Translucency Measurements for First-Trimester Screening: The ‘Price’ of Inaccuracy

2007

Self Cite

View full text Add to dashboard Cite

Objective: First-trimester aneuploidy screening is in transition from the phase of ‘development’ to that of ‘diffusion.’ As with all other technologies, there is risk of diminished performance until newer centers are well experienced. Typically, inexperienced sonographers under-measure nuchal translucency (NT), and experience, training and continual monitoring of data are needed to ensure that measurements do not deviate. Here we assess the impact of systematic under-measurement on abnormality detection. Study Design: Actual NT measurements from 13,887 normal fetuses, 82 with trisomy 21 (T21) and 61 with other abnormalities (OA) with birth outcome data were mathematically modified to show either a 25% or 0.5-mm decrease in measurement. The impact upon sensitivity and screen-positive rates were assessed. Results: Reducing the NT measurements of T21 and OA cases lowers the sensitivity from 81.7 and 70.5%, respectively, to 67.1 and 62.3% (p < 0.01). If normals are correspondingly lowered, then the screen-positive rates are reduced from 6.9 to 2.0 and 2.5%. To maintain the same screen-positive rates and sensitivity, the risk threshold would have to be increased from 1/300 to 1/556. Conclusion: Minor inaccuracies in NT measurements as small as 25% or 0.5 mm will have very significant negative impacts upon abnormality detection, reducing detection rates by 18% (81.7 to 67.1%). Just as it is completely accepted that laboratory measurements require standardization and quality assurance, NT measurements, because they are used in an algorithm, need to be treated with the same rigor. That way the published data from centers that have developed such screening can be applied by other operators at other sites when counseling their patients.

show abstract

Section: Introductionmentioning

confidence: 99%

Nuchal Translucency Measurements for First-Trimester Screening: The ‘Price’ of Inaccuracy

2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…AFP, P-hCG, and estriol are commonly used in screening for Down's syndrome [4], However, efforts to enable earlier diagnosis have expanded the search for other possible markers, including PAPP-A, Inhibin, and urinary (3-core hCG [5,6], Estradiol, PAI-2, and many other protein markers have also been theorized to predict pregnancy outcomes. Serum progesterone has been used to discrimi nate between normal and abnormal pregnancies.…”

Section: Introductionmentioning

confidence: 99%

Urinary β-Core Fragment as a Predictor of Abnormal Pregnancy at 4–6 Weeks’ Gestation

et al. 1997

Self Cite

View full text Add to dashboard Cite

Currently, transvaginal ultrasound and serial serum β-hCG measurements are used to differentiate normal versus abnormal gestations in the first trimester of pregnancy. These techniques have been found to be ineffective when the gestations are earlier than 6 weeks. This study was conducted to determine if urinary β-core fragment, the urine degradation product of β-hCG, could be used to distinguish normal from abnormal gestations between 4 and 6 weeks. Urine samples were obtained from 27 patients on initial presentation to the emergency room or outpatient settings with gestations at 4–6 weeks by sure last menstrual period. The urine was then frozen at ––40 °C and sent for β-core assay analysis. Eighteen women with normal intrauterine pregnancies and nine abnormal pregnancies, including ectopics and spontaneous abortions, were studied. Pearson correlations were performed with a p < 0.05 considered significant. In the normal gestations, there was a positive correlation between β-core fragment and gestational age at 4–6 weeks (r = 0.461, p < 0.05). This correlation was not evident in abnormal gestations (r = 0.360, p = 0.34). In early pregnancy, β-core fragment correlates positively with gestational age which is not apparent in abnormal counterparts. This finding suggests that urinary β-core fragment may be a promising marker to differentiate normal early pregnancies from abnormal gestations.

show abstract

“…Screening of all pregnant women for NTDs and aneuploidy, using maternal serum biochemical markers, is generally recognized now as a standard of care in obstetric 304 Fetal Diagn Ther 1998;13: [302][303][304] Feldman/Dvorin/Phillips/Kramer/Johnson/ Evans practice [3,4]. Most states within the United States and many other countries worldwide adopted laws or regulations addressing maternal serum screening [5].…”

Section: Discussionmentioning

confidence: 99%

2nd-Trimester Maternal Serum Marker Results Are Not Altered by Delayed Analysis

et al. 1998

Self Cite

View full text Add to dashboard Cite

Objective: The goal of the study was to evaluate the significance of delayed laboratory analysis of maternal serum α-fetoprotein, β-subunit of human chorionic gonadotropin, and unconjugated estriol for prenatal screening. Methods: Biochemical analysis of 30 consecutive biochemical screening specimens of maternal serum α-fetoprotein, β-subunit of human chorionic gonadotropin, and unconjugated estriol was performed immediately upon arrival to the laboratory, 7 days later, and again 14 days after maternal blood was drawn. Differences among the results of the three sets of biochemical studies were evaluated by one-way analysis of variance for repeated measures. Results: No significant differences were found among the results of immediate assays as compared with those at a 7- or a 14-day delay for all three biochemical markers. Conclusions: Our data suggest that up to a 14-day delay in the performance of the 2nd-trimester maternal serum biochemical screening assays will not alter the results significantly. The results of maternal serum screening are, thus, clinically valid even if the laboratory assays were performed several days after maternal blood was drawn.

show abstract

Biochemical screening

Cited by 13 publications

References 0 publications

Nuchal Translucency Measurements for First-Trimester Screening: The ‘Price’ of Inaccuracy

Nuchal Translucency Measurements for First-Trimester Screening: The ‘Price’ of Inaccuracy

Urinary β-Core Fragment as a Predictor of Abnormal Pregnancy at 4–6 Weeks’ Gestation

2nd-Trimester Maternal Serum Marker Results Are Not Altered by Delayed Analysis

Contact Info

Product

Resources

About