Risk calculators have been created for Trisomy 21, Trisomy 18, and All Chromosomal Defects

This is an example of Risk Calculators for Trisomy 21. The three calculators are based upon the skill of the examiner. Clicking each button will display the respective calculator.

The calculator lists the markers and their respective likelihood ratios.

The first step is to enter the risk for Down syndrome based upon the maternal age, or the risk from maternal serum screening, or first-trimester nuchal translucency screening (Step 1). In this example, the risk is 1 in 300. Therefore, 300 is entered (Step 1) and the Enter button clicked (Step 2).

In this patient the fetus has tricuspid regurgitation. This is checked (Step 3).

To compute the risk, click the COMPUTE button (Step 4). The risk is displayed as the mean, and the 5% adn 95% condifence intervals.