Maternal Serum Screening (MSS)

Last updated 25.08.13

 

Definition

-    Maternal blood test to determine risk of neural tube defects, Trisomy 18 & Trisomy 21 (Down Syndrome)

 

Features

-    In Victoria performed by Victorian Clinical Genetic Services (VCGS)

-     Path slips can be requested on 1300 934 355

-     Samples processed at Royal Childrens Hospital

-    3-5% come back as high risk (>1:300)

-    Request needs to include

-     Maternal age or Age of egg if IVF

-    Also type of IVF: frozen, fresh

-     Weight

-     EDD & what based on (US or LMP)

-     Note if previous Down syndrome pregnancy

 

Types

-    Combined First Trimester Screening

-     Blood test at 10/40

-    Can be done between 9-13+6/40

-    Free Beta HCG: increased

-    PAPP-A: decreased

-     NT US at 11-14/40

-    Can be done between 11+1-13+6/40

-     Tests for Trisomy 18 & Trisomy 21 (Down Syndrome)

-    85-90% sensitivity for Trisomy 21 (Down Syndrome)

-     Results available after NT US

-     95% results available within 1 week of NT US

-     Costs $100 out of pocket with ?$30 rebate

-    Second Trimester Screening = Quad Test

-     Blood test at 15-17/40

-    Can be done between 14-20/40

-    Free Beta hCG

-    Unconjugated oestradiol

-    AFP

-    Inhibin A

-     Tests for neural tube defects, Trisomy 18 & Trisomy 21 (Down Syndrome)

-     Costs $55.25 out of pocket with ?$30 rebate

-     95% results available within 1 week

 

 

References

 

www.vcgs.org.au