Prenatal Diagnosis for Increased Risk of Down Syndrome
Description:
Quantitative fluorescence PCR (QF-PCR) is an efficient and highly accurate method for the rapid detection of trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), trisomy 13 (Patau syndrome) and triploidy. The X and Y chromosomes can also be investigated where aneuploidy is suspected. When chromosome aneuploidy is detected futher analysis of cultured cells is performed by G-banded chromosome analysis.
Clinical details:
All prenatal samples referred to our laboratory are tested using QF-PCR as a first test. The following groups of women are suitable for rapid aneuploidy exclusion only.
Risk > 1:250 following Down Syndrome screening using a nationally approved Down syndrome screening test, e.g. the combined, triple or quadruple test, or > 1:150 using the integrated test.
Women undergoing invasive testing for a molecular genetic or biochemical genetic disorder (cystic fibrosis, thalassaemia etc) because of a relevant family history or because of a risk identified in their current pregnancy (e.g. following carrier screening for haemoglobinopathies).
Women undergoing other invasive procedures, e.g. transfusion for RhD.
If chromosome aneuploidy is detected futher analysis of cultured cells is performed by G-banded chromosome analysis in order to determine the recurrence risk for the couple.
Risk > 1:250 following Down Syndrome screening using a nationally approved Down syndrome screening test, e.g. the combined, triple or quadruple test, or > 1:150 using the integrated test.
Women undergoing invasive testing for a molecular genetic or biochemical genetic disorder (cystic fibrosis, thalassaemia etc) because of a relevant family history or because of a risk identified in their current pregnancy (e.g. following carrier screening for haemoglobinopathies).
Women undergoing other invasive procedures, e.g. transfusion for RhD.
If chromosome aneuploidy is detected futher analysis of cultured cells is performed by G-banded chromosome analysis in order to determine the recurrence risk for the couple.
Synonyms or keywords:
Rapid Aneuploidy Detection, Karyotyping, Chromosomes, QF-PCR, Turner sydnrome, Prenatal testing, CVS. AF.
Department:
Location:
Sample type and Volume required:
DNA sample (50ng), amniotic fluid in a dry sterile container (20ml), CVS (20mg) (please discuss with the laboratory)
Call in advance:
Please notify the laboratory before sending prenatal samples
Turnaround time:
1 - 3 working days
Special sample instructions:
Request form available at: https://southeastgenomics.nhs.uk/wp-content/uploads/2023/08/SE-GLH-Non-WGS-Genetic-Test-Request-Form-August-2023-v1.5.pdf
- R401 Common aneuploidy testing - prenatal
Include the relevant R code (above) on the referral form; for further details and the eligibility criteria for testing please see https://www.england.nhs.uk/publication/national-genomic-test-directories/
Storage and transport:
All prenatal samples must arrive in the laboratory on the day of sampling, preferably before 3pm.
Cost:
On application
Time limit for extra tests:
Do not spin down or freeze samples before sending.
Contacts:
For clinical advice or interpretation of results, please contact the laboratory in the first instance.
Laboratory:
Last updated: 26/10/2023
