Prenatal Diagnosis

Introduction

Prenatal diagnosis is the process of evaluating the presence of disease or potential disease in the fetus. This enables families to be better prepared before the birth of the baby.

The Prenatal Diagnostic & Counselling Service including Mrs. Wu Chung Prenatal Diagnostic Laboratory was established at Tsan Yuk Hospital in 1981.

The Prenatal Diagnostic & Counselling team accepts referrals for prepregnancy counselling, pre-implantation genetic diagnosis, prenatal diagnosis, counselling & therapy, and provides prenatal screening and diagnosis of chromosomal disorders, metabolic and genetic disorders and fetal anomalies.

Clinical Services
Prenatal Screening for thalassaemia, Down syndrome, and structural abnormalities
  • Antenatal screening for thalassaemia
  • Nuchal translucency for fetal Down syndrome screening in multiple pregnancy
  • First trimester combined, integrated, or second trimester serum screening for fetal Down syndrome
  • 19 to 21 week fetal morphology scan

Non-invasive and invasive prenatal diagnosis
  • Targeted 2D ultrasound examination in 1st and 2nd trimester
  • Fetal echocardiography (joint consultation with paediatric cardiologist)
  • 3D/4D ultrasound examination
  • Noninvasive ultrasound diagnosis of a-thalassaemia
  • Invasive diagnostic procedures including amniocentesis, chorionic villus sampling, cordocentesis, embryoscopy, hysterofetoscopy

Medical and surgical fetal therapy
  • Various shunting procedures for fetal disorders such as urethral obstruction or pleural effusion
  • Laser photocoagulation for twin abnormalities such as severe twin-twin transfusion syndrome
  • In-utero transfusion for treatment of fetal anaemia
  • Amnio-reduction
  • Medical treatment for cardiac arrhythmia
  • Radiofrequency ablation for complicated multiple pregnancies

Fetal monitoring for high risk pregnancies
  • Multiple pregnancies
  • Intrauterine growth restriction
  • Fetal abnormalities
  • Rhesus isoimmunisation

Multidisciplinary genetic counseling
  • Joint counseling for fetal anomalies with clinical geneticists, paediatricians or paediatric surgeons
  • Prepregnancy counselling
  • Pre-implantation genetic testing
  • Pregnancy following preimplantation genetic testing

Laboratory Services
History of Prenatal Diagnostic Laboratory

The Mrs. Wu Chung Prenatal Diagnostic Laboratory was established by the Department of Obstetrics and Gynaecology of the University of Hong Kong in 1981. The capital cost of the laboratory was paid by the Hong Kong Government and by a donation from Mrs. Wu Chung. The operation cost was paid by the Hong Kong Government until December 1991 and then by the Hospital Authority who came over the management of all the government hospitals in December 1991. Staff members of the laboratory are employed by the Hospital Authority and the University of Hong Kong. The laboratory is providing prenatal diagnostic and screening laboratory service in Hong Kong. The laboratory is accredited by HOKLAS (ISO 15189, International Organisation for Standardization (ISO) standard for medical laboratories) with scope of tests as specified in HOKLAS Directory of Accredited Laboratories.


Chromosomes and molecular genetic analysis for prenatal diagnosis (Chromosomal microarray, karyotype, QF-PCR, molecular genetics analysis, Whole Exome Sequencing)
Instructions to doctors on sending samples HA PRIVATE
Request form HA / PRIVATE
Consent form for genetic testing
遺傳檢驗同意書
ENGLISH 繁體
Diagrams for illustrating Chromosomal Microarray (CMA) testing
基因體晶片(CMA)檢測圖表說明
Download PDF 
Information on Prenatal Chromosomal Microarray (CMA) Testing (HA)
產前基因體晶片(CMA)檢測資料 (HA)
Information on Prenatal Chromosomal Microarray (CMA) Testing (Private)
產前基因體晶片(CMA)檢測資料 (Private)
Prenatal Chromosomal Microarray (CMA) Testing pamphlet
產前基因體晶片(CMA)檢測小册子
ENGLISH 繁體 
Fragile X testing pamphlet
Download PDF 
Information on Prenatal Exome Sequencing (HA)

產前外顯子組測序檢測資料 (HA)

ENGLISH 繁體

Thalassaemia Genetic Testing
Instructions to doctors on sending samples HA PRIVATE
Request form HA / PRIVATE
Thalassaemia Screen Request HA / PRIVATE
Consent form for genetic testing
遺傳檢驗同意書
ENGLISH 繁體

Chromosomes and Y-microdeletion analysis for reproductive medicine investigation
Instructions to doctors on sending samples HA PRIVATE
Request form HA / PRIVATE
Consent form for Genetic Tests in Reproductive Medicine
生殖醫學遺傳檢驗同意書
ENGLISH 繁體

Down syndrome screening
Instructions to doctors on sending samples HA PRIVATE
Request forms for
  • 1st trimester nuchal screening
  • 1st trimester (combined) screening test
  • 2nd trimester quadruple screening test
Provide upon request

Chromosomes and molecular genetic analysis for postnatal study
Instructions to doctors on sending samples HA PRIVATE
Request form HA / PRIVATE
Consent form for genetic testing
遺傳檢驗同意書
ENGLISH 繁體
Diagrams for illustrating Chromosomal Microarray (CMA) testing
基因體晶片(CMA)檢測圖表說明
Download PDF 
Information on Postnatal Chromosomal Microarray (CMA) Testing
基因體晶片(CMA)檢測資料
ENGLISH  繁體
Postnatal Chromosomal Microarray (CMA) Testing pamphlet
基因體晶片(CMA)檢測小册子
ENGLISH 繁體 

Scope of Services
Cytogenetic, molecular genetic, haematological and biochemical tests for prenatal screening and diagnosis
Laboratory Services
Cytogenetic tests

Karyotyping is a test to examine chromosomes in a prenatal and postnatal sample of cultured cells, which can help to identify the numerical and structural abnormalities in chromosome. The test can be performed on different tissues, including


  • Chorionic villi
  • Amniotic fluid
  • Peripheral, cord and fetal blood
  • Tissue and skin biopsy
Molecular tests

Molecular diagnostic and screening tests can provide rapid, sensitive and accurate genetic diagnosis.


  1. Rapid Aneuploidy Detection for chromosomes 13,18,21 and sex chromosomes (QF-PCR)
  2. DiGeorge syndrome (22q11.2) microdeletion Detection
  1. Fluorescence in situ hybridisation (FISH) analysis
    • conventional FISH
    • multi color FISH(m-FISH)
    • multi color banding (mBand)
  1. Chromosomal Microarray (CMA)

CMA is a special test which finds differences in the amount of genetic material among individuals. It is more sensitive than traditional cytogenetic Karyotyping and is able to find a chromosome gain or loss even if testing of the chromosome by Karyotyping shows normal result. For more information including request and consent forms, please visit Chromosomes and molecular genetics analysis for prenatal diagnosis and postnatal study

  1. Molecular diagnosis of other genetic conditions
    • Uniparental disomy by short tandem repeats
    • Duchene muscular dystrophy (DMD)
    • Spinal muscular atrophy (SMN1)
    • Huntington disease (CAG repeats)
    • Thanatophoric dysplasia (FGFR3)
    • Apert syndrome (FGFR2)
    • Erythropoietic protoporphyria (FECH)
Reproductive medicine investigations
Down syndrome screening tests

The markers of first trimester combined screening test include maternal age, nuchal translucency (NT) and biochemical markers. Combining the marker levels together with maternal age, the risk of having a Down syndrome pregnancy can be estimated by mathematical modeling. Women are screened positive if their risks are higher than the specified cut-off value.

There are three kinds of Down syndrome screening tests offered by our laboratory

  • First trimester combined test (gestation 11-13+6 weeks)
  • Second trimester biochemical test (gestation 16 to 19+6 weeks)
  • First trimester nuchal translucency test ( for multiple pregnancy)
Haematological and genetic tests for inherited blood disorders

Thalassemia is the consequence of an imbalance in alpha and beta globin chain synthesis. Excess alpha or beta chains are insoluble in red blood cells. Precipitated globin genes damage red cell membrane thus shortening red cell half life.

Haemophilia disease is due to genetic defect in blood clotting factors impairing coagulation when a blood vessel is broken.

  • Molecular diagnosis of alpha and beta thalassaemia
  • Molecular diagnosis of haemophilia A and B (clotting factor VIII and IX deficiency)
  • Molecular diagnosis of factor VII deficiency
Staff
Laboratory Director: Mr. W.K. TAM
Clinical Consultants: Dr. Mary H.Y. TANG
Dr. Anita S.Y. KAN
Quality Manager: Dr. Sandy L.K. AU
Contact and Complaint
Address: Room 210,
Tsan Yuk Hospital 30 Hospital Road,
Sai Ying Pun, Hong Kong
Telephone: (852)-2589-2288
Fax: (852)-2517-2373
Website: web.obsgyn.hku.hk/PDL/
Useful links

Training

Our department is recognized by the Royal College of Obstetricians & Gynaecologists as a training centre for maternal fetal medicine subspecialists since 2000. We offer training in prenatal diagnosis and ultrasound examination for:


  • Maternal-fetal medicine subspecialists programme
  • Hospital Authority- level II obstetric and gynaecologic ultrasonography programme
Referral
  • For referrals, please call the prenatal diagnostic and counselling clinic at (852) 2589-2218, or fax referrals to (852) 2517-2373.
  • For laboratory services, please call Mrs. Wu Chung Prenatal Diagnostic Laboratory at (852) 2589- 2288.