Diagnostic testing (typical indications):
- Clinical suspicion of chromosomal aneuploidy 13, 18, 21, X or Y
- High-risk for chromosomal aneuploidy during pregnancy, but prenatal diagnosis not completed
- Molar pregnancy
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% in amniotic fluid and blood samples (PMID: 17108223, 21316319). Test sensitivity can vary depending on DNA quality as well as maternal and fetal cell percentage in the specimen
This analysis allows the detection in parallel of fetal and maternal STRs 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. Cell contamination from maternal or fetal origin is also assessed. Low-level cell contamination 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. Unusual genetic variants, genetic recombination, and rare genotyping errors can result in inaccurate diagnosis. Depending on samples provided, presence of significant cell contamination of maternal or fetal origin can result in inaccurate diagnosis. The ability to amplify all STRs regions is highly dependent on the quality of the DNA, and therefore poor quality DNA may result in an inconclusive result. This test is a PCR-based assay. Therefore, variants located in primer binding sites can result in allelic dropout and consequently an erroneous result.
Turnaround time: 3-5 working days
Specimen accepted:
- 1 x 4 mL blood in EDTA tubes (purple top tube) – 2 mL for newborns
- Fetal cord blood: 500 ul in EDTA tube (purple top tube)
- FFPE specimen : 10 x 5 um scrolls in 1.5 ml tube or 6 x 5 um unstained slides
- For any other sample type, contact the laboratory for testing availability
If fetal cord blood sample is provided, it 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.