Evaluation of the impact of density gradient centrifugation on fetal cell loss during enrichment from maternal peripheral blood


  • Funding sources: This study was partly supported by an operating grant from the Canadian Institute for Health Research (CIHR) and MetaSystems through the University-Industry Program to R. D. and the Canada Research Chair Program to R. D. A. E. is a student scholar of the Public Health Ministry of Egypt. R. D. held a Canada Research Chair in Genetics, Mutagenesis, and Cancer. R. D. is member of the FRQS-funded Centre de Recherche Clinique Étienne-Le Bel. The Cell Imaging Facility of the Faculty of Medicine and Health Sciences, Université de Sherbrooke, was funded by grants from the Canadian Foundation for Innovation and from the Centre de Recherche Clinique Étienne-Le Bel.

  • Conflicts of interest: None declared.



Physical separation by density gradient centrifugation (DGC) is usually used as an initial step of multistep enrichment protocols for purification of fetal cells (FCs) from maternal blood. Many protocols were designed but no single approach was efficient enough to provide noninvasive prenatal diagnosis. Procedures and methods were difficult to compare because of the nonuniformity of protocols among different groups. Recovery of FCs is jeopardized by their loss during the process of enrichment. Any loss of FCs must be minimized because of the multiplicative effect of each step of the enrichment process. The main objective of this study was to evaluate FC loss caused by DGC.


Fetal cells were quantified in peripheral blood samples obtained from both euploid and aneuploid pregnancies before and after enrichment by buoyant DGC using Histopaque 1.119 g/mL.


Density gradient centrifugation results in major loss of 60% to 80% of rare FCs, which may further complicate subsequent enrichment procedures. Eliminating aggressive manipulations can significantly minimize FC loss.


Data obtained raise questions about the appropriateness of the DGC step for the enrichment of rare FCs and argues for the use of the alternative nonaggressive version of the procedure presented here or prioritizing other methods of enrichments. © 2014 John Wiley & Sons, Ltd.