Thank you for your query.
Double Marker Test is an important and significant test for pregnant women.
This test must be performed from 9 to 13.6 weeks pregnancy
but only after performing an ultrasound
Because,at this time period scan report shows various measurements of the fetus,in that measurements one important one was Nuchal translucency or NT .This NT is nothing but the translucent area at the back of the baby's neck.This translucency is because of the fluid present and thickness of this area advises to go for further analysis. This area diminishes after 14 weeks and is of no use in testing later on.
Regarding NT :
High Normal range: 2.5-3.5
Danger Range: > 3.5
These results are valid for the scan taken at any time from 9 to 13.6 weeks.
This test Helps us to know whether baby is at risk for Mental Disorders mainly Down's syndrome. Trisomy 18 and trisomy 21
.These three disorders are because of chromosomal defects and could cause serious problems.
Free Beta HCG: Presence in High levels indicate risk for Down'syndrome and in low level for Trisomy 18 and 21
PAPP-A(Pregnancy Associated Plasma Protein):Presence in low level indicates risk for Down's syndrome and Trisomy 18 and 21.
So, based on the levels of these markers results will be given.
Results are interpreted as "SCREEN POSITIVE" which indicates HIGH RISK and "SCREEN NEGATIVE" shows LOW RISK for Down's syndrome,Trisomy 18 and 21. The results are given not only based on values of those two markers but also on the basis of mother's age and fetal age(given during Ultrasound).The age here plays an important role because,mother with the age over 35 are more vulnerable than who are in their 20's.So, finally results are given in a Ratio that is,
SCREEN POSITIVE: HIGH RISK- 1:10 AND CUT OFF RANGE IS 1:250
SCREEN NEGATIVE: LOW RISK-1:1000 AND ABOVE.
Green Zone in the graph indicates low risk for the baby,Yellow region is borderline and Red zone indicates a high risk
After Reporting this results to your doctor they will tell whether there is a need for further testing such as AMNIOCENTESIS
or CHORIONIC VILLUS SAMPLING(advanced tests to confirm if the results are screen positive)
You need to post the complete report alongwith NT etc for me to comment.