NIPT for Down syndrome screening
Down syndrome screening
Down syndrome is caused by an extra copy of Chromosome 21 in the human cells. It is the most common chromosomal abnormality and the most common genetic cause of mental retardation. The local incidence is around 1 in 800. The first-trimester combined Down syndrome screening test (fetal nuchal translucency NT measurement plus maternal biochemical blood test) detects around 90 out of 100 Down syndrome, but around 5 out of 100 normal babies would be reported as high risk. A more accurate screening test called NIPT (non-invasive prenatal test) is now available.
What is NIPT?
People normally have 23 pairs of chromosomes in each cell. Each chromosome is made up of a coil of DNA. Besides her own DNA, mother’s blood also contain small amount of fetal DNA. Therefore, it allows accurate screening for fetal Down syndrome using mother’s blood. If the baby has Down syndrome, the test will show increased amount of DNA from chromosome 21.
NIPT detects around 99 out of 100 Down syndrome, and only around 1 out of 1000 normal babies would be reported as high risk. It also detects Edward syndrome (an extra copy of chromosome 18), Patau syndrome (an extra copy of chromosome 13) and Turner syndrome (only 1 copy of chromosome X).
NIPT is not currently available in Hospital Authority, but is available in The Chinese University of Hong Kong Fetal Medicine Private Clinic as well as other private clinics and hospitals in Hong Kong.
There are several brands of NIPT presently available in the market, e.g., SafeT21express, Panorama, NIFTY, verifi, Harmony, Prenetics V.
Gestational age for NIPT
From 10 gestational weeks onwards
Around 7 working days after blood taking
Charge (consultation, ultrasound and blood test)
HKD$5,700 singleton pregnancy
HKD$6,400 twins pregnancy
– Chromosome 21 (Down syndrome) 13 18 X Y + 7 microdeletion syndromes
Other information about NIPT
Pregnant women are recommended to have a dating scan to determine the exact gestational age which is important for all forms of Down syndrome screening. This service is also available in The Chinese University of Hong Kong Fetal Medicine Private Clinic. NIPT can be done at the same time if the gestational age is beyond 10 weeks.
How to make an appointment
In person :
The Chinese University of Hong Kong Fetal Medicine Private Clinic, Room 30, 2/F, Li Ka Shing Specialist Out-patient Clinic South Wing, Prince of Wales Hospital
By phone :
Call The Chinese University of Hong Kong Fetal Medicine Private Clinic direct line (852) 5600 1970 or leave a message at (852) 3505 4219 (Please leave your name and telephone number)
By fax :
Please download the NIPT pamphlet from the link below, complete the form and fax it to The Chinese University of Hong Kong Fetal Medicine Private Clinic at (852) 2632 5065
The content on this page does not include all the information about NIPT. Doctor’s counselling is essential before you undergo NIPT. Our department reserves the right to amend any information on this page without prior notice.