CellFree DNA Prenatal Screen

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General Information

Lab Name
CellFree DNA Prenatal Screen
Lab Code
PDNAS
Epic Ordering
Cell-Free DNA Prenatal Screen
Description

This screening test evaluates the copy number state for all 46 chromosomes, including common aneuploidies (trisomy 13, 18, 21, and sex chromosomes). Individualized patient-provider discussion is highly recommended prior to ordering.

Ordering Requirements:

  • Singleton Pregnancies:
    • For orders submitted electronically via Epic, providers must complete the Clinical Order Questions in Epic or submit a completed UW Genetics Clinical Lab Request Form.
    • Submissions from outside (reference lab) clients must be accompanied by a completed UW Genetics Clinical Lab Request form.

  • Twin Pregnancies: For twin pregnancies, samples are sent out to Illumina. Refer to separate test #484, "Twin cfDNA Prenatal Aneuploidy Screen (Sendout)."
Forms & Requisitions

UW Genetics Clinical Lab Request

Synonyms
cell-free fetal DNA, cfDNA, Down syndrome, fetal chromosome aneuploidy screen, NIPS, NIPT, noninvasive prenatal screening, noninvasive prenatal testing, Placental DNA, Trisomy 13, Trisomy 18, Trisomy 21, Turner syndrome
Components

Interpretation

Method

Massively parallel sequencing of total cell-free DNA (cfDNA)

Reference Range
See individual components
Guidelines

Ordering & Collection

Specimen Type
Whole blood
Collection

Two 10 mL whole blood in Streck Cell-Free DNA BCT® tubes (mottled black and tan).

Gently mix blood by inverting tube 8-10 times.

Do not send samples via pneumatic tube system. Samples collected in Streck tubes must be walked to the laboratory.

Forms & Requisitions

UW Genetics Clinical Lab Request

Handling Instructions

Walk samples to the laboratory after collection. Do NOT use the pneumatic tube system, as this may compromise the sample.

Quantity
requested: 20 mL whole blood
minimum: 7 mL whole blood

Processing

Processing

Note: For twin pregnancies, refer to test #484, Twin cfDNA Prenatal Aneuploidy Screen (Sendout).

Store whole blood at room temperature. Do not freeze. For orders not placed in Epic, a completed UW Genetics Clinical Lab Request form is required.

At the cfDNA Panel (PDNAP) prompt, enter PSFULL for "Full prenatal test with chromosomes 21, 18, 13 PLUS sex chromosome aneuploidies."

Enter PSAU for "Limited prenatal test for chromosomes 21, 18, 13 ONLY."

Stability: Ambient: 5 days

Transport Temperature

Performance

LIS Dept Code
Genetics (GEN)
Performing Location(s)
UW-MT Genetics

Attention: Genetics Lab
Clinical lab, Room NW220
University of Washington Medical Center
1959 NE Pacific Street
Seattle, WA 98195

Tel: 206-598–6429 M–F (7:30 AM–4:00 PM)
Fax: 206-598–0304
Lab email: genelab@uw.edu

Tel (EXOME only): 206-543-0459

Manager

Joe Bernal, jbernal@uw.edu

Genetic Counselors

Angela Jacobson, MS, LGC agibson@uw.edu
Sandra Coe, MS,LGC, scoe20@uw.edu
Dru Leistritz, MS, LGC, dru2@uw.edu (EXOME testing only)
Daniel W. Serber, PhD, MS, LCGC, dwserber@uw.edu

Variant Review Scientist

Ankita Jhuraney, PhD
Sarah Paolucci, MA, MS, LGC, spaolucc@uw.edu
Catherine A. Darcey, MSc

Faculty

Colin C. Pritchard, MD, PhD
Brian H. Shirts, MD, PhD
Christina Lockwood, PhD, DABCC
Stephen Salipante, MD, PhD
Eric Konnick, MD, MS
Niklas Krumm, MD,PhD
Vera Paulson, MD, PhD
Jillian Buchan, PhD, FACMG

Frequency
Turnaround time 8-10 business days
Available STAT?
No

Billing & Coding

CPT codes
81420
Billing Comments

81420

LOINC
73967-2