Fetal cell-free plasma DNA concentrations in maternal blood are stable 24 hours after collection: analysis of first- and third-trimester samples.

Author(s): Angert RM, LeShane ES, Lo YM, Chan LY, Delli-Bovi LC, Bianchi DW

Publication: Clin Chem, 2003, Vol. 49, Page 195-8

PubMed ID: 12507985 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of room temperature storage of whole blood prior to centrifugation on the quantification of fetal cell free plasma DNA by taqman real-time PCR. Aliquots of blood were removed from the room temperature agitator at each time-point, centrifuged, and the plasma was frozen. After thawing, EDTA-plasma was centrifuged again and transferred to a new tube. DNA was extracted from plasma using the QIAamp Mini Blood Kit and stored at 4 degrees C. Specimens collected late in gestation were sent from the United States to Hong Kong.

   Summary of Findings:

   In plasma from women 6-27 weeks pregnant, the beta-globin copy number increased when whole blood was stored at room temperature for more than 4 h prior to centrifugation (p<0.001), but the normalized copies of fetal cell-free DYS1 were not affected by pre-centrifugation storage of whole blood. Beta-globin copy number was unaffected by fetal gender. Plasma from women who were 25-33 weeks pregnant had higher beta-globin copy numbers when blood was stored for 24 h at room temperature prior to centrifugation compared to when blood was centrifuged immediately (p=0.022). DYS14 copy number in specimens from women 25-33 weeks pregnant was not affected by pre-centrifugation storage.

   Biospecimens

   • Bodily Fluid - Blood
   • Bodily Fluid - Plasma

   Preservative Types

   • Frozen

   Diagnoses:

   • Pregnant

   Platform:

   Analyte	Technology Platform
   DNA	Real-time qPCR

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Time at room temperature	15 min 30 min 1 h 2 h 4 h 6 h 24 h
   Preaquisition	Diagnosis/ patient condition	6-17 weeks pregnant 25-33 weeks pregnant
   Preaquisition	Patient gender	Female Male
   Biospecimen Aliquots and Components	Centrifugation	Centrifugation delays investigated

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