Fetal Genotyping from Maternal Plasma

Test description

Blood group genotyping of fetal DNA is performed to predict the blood group antigen status of the fetus at high risk for Hemolytic Disease of the Fetus and Newborn (HDFN). Because cell-free fetal DNA is normally present in maternal blood plasma throughout pregnancy, a non-invasive venipuncture sample can be collected from the mother for testing without risk to the fetus. 

Fetal Genotyping from Maternal Plasma Instructions (PDF)

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Testing Schedule

  • For RhD, Rhc, RhE and RhC antigens, submit mother’s sample > 16 weeks gestation.
  • For K (Kell) antigen, submit mother’s sample > 28 weeks gestation.

Specimen and requisition requirements

Certain test criteria must be met prior to testing. CBS Laboratory Supervisor must be contacted prior to patient sample collection. Refer to 

Fetal Genotyping on Maternal Plasma Maternal Fetal Medicine Instructions (PDF).

Label specimen with the required minimum information: patient’s last name, first name, PHN or unique identifier and date of collection.

Requisition must include, as applicable:

  • Patient's Last name, First name, Date of Birth and PHN or unique identifier.
  • Expected date of delivery (EDD)
  • Clinic and Health Care Provider Name. Complete address, phone and fax number
  • Phlebotomist ID information
  • Date of collection

Download requisitions and related documents:

 

Must be kept at room temperature (18-30°C).

Shipping instructions

For shipping instructions refer to Fetal Genotyping on Maternal Plasma Maternal Fetal Medicine Instructions

Send to

Canadian Blood Services
BC & Yukon Centre
Diagnostic Services Laboratory
4750 Oak Street
Vancouver, BC  V6H 2N9
Tel: 604-707-3434
Fax: 604-874-6582