Optimizing blood collection, transport and storage conditions for cell free DNA increases access to prenatal testing

Abstract

Objectives: Fetal mutations and fetal chromosomal abnormalities can be detected by molecular analysis of circulating cell free fetal DNA (ccffDNA) from maternal plasma. This comprehensive study was aimed to investigate and verify blood collection and blood shipping conditions that enable Noninvasive Prenatal Testing. Specifically, the impact of shipping and storage on the stability and concentration of circulating cell-free DNA (ccfDNA) in Streck® Cell-Free DNA™ Blood Collection Tubes (Streck BCTs, Streck, Omaha NE). These BCTs were designed to minimize cellular degradation, and thus effectively prevent dilution of fetal ccf DNA by maternal genomic DNA, was evaluated.

Design and methods: Peripheral venous maternal blood was collected into Streck BCTs to investigate four aspects of handling and processing conditions: (1) time from blood draw to plasma processing; (2) storage temperature; (3) mechanical stress; and (4) lot-to-lot tube variations.

Results: Maternal blood stored in Streck BCTs for up to 7 days at ambient temperature provides stable concentrations of ccffDNA. The amount of fetal DNA did not change over a broad range of storage temperatures (4°C, 23°C, 37°C, 40°C), but the amount of total (largely maternal) DNA increased in samples stored at 23°C and above, indicating maternal cell degradation and genomic DNA release at elevated temperatures. Shipping maternal blood in Streck BCTs, did not affect sample quality.

Conclusions: Maternal plasma DNA stabilized for 0 to 7 days in Streck BCTs can be used for non-invasive prenatal molecular applications, when temperatures are maintained within the broad parameters assessed in this study.

Keywords: BCT; Blood preservation; Circulating cell free DNA; FF; FQA; Fetal DNA; Fetal Quantifier Assay; IRB; Institutional Review Board; MALDI-TOF MS; MPS; Maternal plasma; NIPT; NSC; NTC; Non-invasive prenatal testing; Streck® Cell-free DNA™ BCTs; blood collection tube; ccf; ccffDNA; circulating cell-free; circulating cell-free fetal DNA; fetal fraction; massively parallel sequencing; matrix-assisted laser desorption/ionization time-of-flight mass spectrometer; no storage control; no template control; non-invasive prenatal testing.