Diagnostic testing (typical indications):
- Intra-uterine fetal demise
- High-risk for chromosomal aneuploidy 13, 18, 21, X or Y based on prenatal screening, NIPT or a previously affected pregnancy
- Indicative fetal ultrasound findings
- Pregnancy at risk for another disorder and for which prenatal diagnosis is being ordered
QF-PCR allows for rapid diagnosis of aneuploidies of chromosomes 13, 18 and 21, and X and Y by genotyping of highly polymorphic chromosome-specific short tandem repeats (STRs) and the sex-specific amelogenin marker in AMXY. The analytical sensitivity and specificity of the test for trisomies 13, 18 and 21 and non-mosaic aneuploidies of sex chromosomes is reported to be higher than 95% (PMID: 17108223, 21316319).
This test is performed in parallel on fetal and maternal DNA samples using the Aneufast QF-PCR kit (v4). Copy number of chromosomes 13, 18, 21, X and Y is examined. At least three informative markers on each chromosome are required for reporting. Equivocal results and other abnormal results are further investigated using additional chromosome-specific STR markers. Maternal cell contamination is also assessed. Low-level maternal cell contamination (less than 20%) is acceptable for interpretation and reporting.
This test will not detect balanced chromosomal rearrangements or any abnormality in any other chromosome than 13, 18, 21, X and Y. It may not detect low level mosaicism (below 30%) and some segmental aneuploidies or chromosome rearrangements involving chromosomes 13, 18, 21, X and Y. Maternal contamination of fetal samples, unusual genetic variants, genetic recombination, and rare genotyping errors can result in inaccurate diagnosis.
Turnaround time: 3-5 working days
Specimens accepted:
- Amniotic fluid: 2 x 1.0 ml EPPENDORF
- Amniotic fluid: 20 ml (for possible further testing)
- Direct CVS: min 10 mg direct villi
- For any other sample type, contact the laboratory for testing availability
All request must be accompanied by a maternal sample (blood or buccal swab) for maternal cell contamination analysis.
Submit your test request using our molecular genetics requisition for Fetal Aneuploidy Analysis by QF-PCR.