Evaluación de la eficacia del cribado prenatal del primer trimestre de embarazo en la Región de Murcia
- David Antón Martínez
- Miguel Boronat García
- María Soledad del Pozo Luengo
- Isabel López Expósito
- Juan Antonio Bafalliu Vidal
- Ascensión Vera Carbonell
- José María Egea Mellado
- Francisco Ruiz Espejo
- Pedro Luis Martínez Hernández
- Francisco Gerardo Cañizares Hernández
ISSN: 1888-4008
Year of publication: 2010
Volume: 3
Issue: 3
Pages: 97-103
Type: Article
More publications in: Revista del laboratorio clínico
Abstract
Introduction: First trimester combined screening test for chromosomal anomalies, with its high sensitivity and specificity, can help predict the risk of carrying a foetus with a chromosomal anomaly. Those pregnant women with a high risk can, after genetic advice, then decide to have an invasive diagnostic test. The aim of this article was to determine the sensitivity, negative predictive value and false positive rate of the first trimester combined screening test in our laboratory. Material and methods: First trimester combined screening test was performed on 4494 pregnant women. The test consists of determining PAPP-A, free ß-HCG and nuchal translucency. Karyotype was found in all pregnant women who had a high risk for Down's Syndrome (DS), Edward's Syndrome (ES) or both. Karyotype of the newborn was used for pregnant women who decided not to have the invasive diagnostic test. Risk was calculated with Prisca Software v.4.0.15.9® (DPC Dipesa®), considering >1/270 as high risk. Results: Out of the total of pregnant women, 260 first trimester screenings had a risk >1/270; 201 for DS, 39 for ES and 20 for both. The data obtained for DS and ES, respectively, were: true positives (TP): 5 and 5; false positives (FP): 216 and 54; true negatives (TN): 4273 and 4435; false negatives (FN): 0 and 0; Sensitivity: 100% for both; Specificity: 95% and 99%. Positive predictive value (PPV): 2% and 8%; negative predictive value (NPV): 100% for both. False positive rate was 4.83% for DS and 1.20% for ES. Conclusion: The first trimester combined screening test is an efficient tool that reduces the number of invasive diagnostic tests, due to its high sensitivity, specificity and negative predictive value.