www.fetalmedicine.hk 29 October 2016
English | 简体 | 繁體


OSCAR stands for "One-Stop Clinic for Assessment of Risk". This is the latest prenatal screening program for Down's Syndrome, introduced from Fetal Medicine Foundation of United Kingom. The screening program is performed during 11-13 (+6d) weeks of gestation, and consists of the measurements of Nuchal Translucency, maternal serum level of Pregnancy Associated Plasma Protein-A (PAPP-A), and free beta-human Chorionic Gonadotropin (free beta-hCG). The chance of having a Down fetus is computed using the above information. This screening test is safe with a detection rate of 90%.

Download Area

Page 1 / Page 2


  1. Firstly, ultrasound scanning is performed to confirm the gestational age and fetal size. The nuchal translucency is also measured.
  2. Blood is then taken from the pregnant woman for PAPP-A and free-beta hCG assay. The result will be available after an hour.
  3. A software issued by Fetal Medicine Foundation will be used to compute the chance of Down's syndrome. The test is regarded as positive if the computed chance is higher than 1:180 for T21, 1:150 for T13 & T18; otherwise it is negative.
  4. About 7% of all women undergoing the screening will have a positive result (high risk). Further invasive procedures such as chorionic villus sampling or amniocentesis will be required to confirm whether the fetus is having Down's syndrome. We recommend chorionic villus sampling as it can be performed before 14 weeks, and have the same risk of amniocentesis (1% abortion rate).
  5. A negative screening test indicate that the chance of having a Down fetus is very low, though it cannot be totally excluded.  Invasive procedures are not indicated.

Comparing OSCAR and other screening programs

Currently in most of the public and private obstetrtic sectors in Hong Kong,  Down's Syndrome is screened by maternal age or second trimester biochemical tests (maternal serum levels of alpha-fetal protein and total hCG). The detection rate is only 30% and 70% respectively.  Moreover, the  biochemical screening cannot be performed until after 16 weeks. Result can only be available few days later. On the other hand, OSCAR can be done before 14 weeks, and the result can be generated in an hour. Its detection rate is the highest among all. The detail scientific report of OSCAR can be viewed from Fetal Medicine Foundation.

How can I join OSCAR?

You can contact us by phone 2632-6412 /2632-4219 or make an appointment via internet.

Content disclaimer  |  Privacy statement  |  Copyright @2014. All Rights Reserved. O&G, CUHK.