Non-Invasive prenatal testing to determine fetal gender


Free fetal DNA may be detected in maternal plasma from early in gestation and used for determination of fetal gender. Total cell-free DNA reflecting both maternal and fetal material is extracted from maternal plasma collected from 7 weeks gestation. Molecular analysis is performed using real time PCR and Taqman MGB probes for the Y-specific SRY and control-CCR5 markers. The presence of SRY marker in duplicate samples is used to indicate the presence of a male fetus and reduce false positives. In the case of detection of total cell free DNA but absence of the SRY marker, indicative of a female fetus we rely on results from repeated analysis at gestation beyond 7 weeks and the cfDNA control marker to discriminate between a true and false negative result.

Also known as

NIPD, NIPT, cffDNA, cell-free fetal DNA sex determination

Request a test

When requesting this test please use the referral form provided. Please also refer to any additional information provided for this test.

Additional information

Please notify laboratory in advance of sending a sample, samples should arrive within 48 hours. Gestation as determined by ultrasound scan is mandatory information to perform this test. This test is not applicable before 7 weeks gestation or in multiple pregnancies including vanishing twin. Testing is only offered to females at risk of having a child with a severe X-linked disorder.

Sending address

Rare & Inherited Disease Laboratory
London North Genomic Laboratory Hub
Great Ormond Street Hospital for Children
Levels 4-6 Barclay House
37 Queen Square

Laboratory service


Sample requirements

20ml blood (EDTA) from mother. Post 9 weeks this can be obtained in one sampling. At 7-9 weeks gestation 2 x 10ml sample should be taken one week apart.

Reference range

Not applicable

Turnaround time

3 days from receipt of second sample

Disease / group



Upon request

Call in advance?

All referrals should be made via a Clinical Genetics Department, please contact the laboratory in advance of sending a sample.� Advance notice is required so samples can be processed rapidly upon receipt


The Genetics Laboratories provide an extensive range of Cytogenetics and Molecular Genetics diagnostic testing services.

© 2011 Great Ormond Street Hospital for Children NHS Trust