J Lab Med Qual Assur.  2015 Mar;37(1):44-46. 10.15263/jlmqa.2015.37.1.44.

An Experience of Using the Harmony Test for Genomics-Based Non-Invasive Prenatal Testing

• Seo DH
• Cho SE
• Kwak JR

• KMID: 1789362
• DOI: http://doi.org/10.15263/jlmqa.2015.37.1.44

Abstract

Serological prenatal screening tests are widely used to detect fetal chromosomal abnormalities such as Down and Edward syndromes. Amniocentesis is conducted as a confirmatory test in the screening-positive case. After discovering of presence of fetal cell-free DNA in maternal blood, non-invasive prenatal test (NIPT) coupled with next generation sequencing are performed in abroad. Results of genomics-based NIPT results supplied to Labgenomics laborotory from June, 2013 to August, 2014 were analyzed. Maternal blood samples were collected into specific Cell-Free DNA BCT tube and were transported. The samples were then delivered to Ariosa Diagnostics by FEDEX. Fetal cell-free DNA samples were analyzed using the Harmony test with sequencing of relevant chromosomes and by using the FORTE (fetal-fraction optimized risk of trisomy evaluation) algorism at Ariosa Diagnostics. In all, 149 cases from 28 medical clinics were analyzed. Six subjects were required recollection of samples because of a low fetal DNA fraction in the initially obtained samples. Of these 6 subjects, no sample could be collected from one. Of the remaining 148 cases, 144 had a low risk of trisomy, and 4 had a high risk for Down syndrome, thus providing a positivity percentage of 2.7%. Fetal DNA fraction in the maternal blood samples ranged from 4.2% to 23.7% with a mean value of 12.0%. We have experienced cases with a high risk for Down syndrome with genomics-based NIPT referred to abroad.

Keyword

Non-invasive prenatal test; Harmony test; Cell-free DNA; Fetal DNA fraction

MeSH Terms

Amniocentesis
Chromosome Aberrations
DNA
Down Syndrome
Prenatal Diagnosis
Trisomy
DNA