alphaOutcome is designed to be used in conjunction with alpha, and gives you the ability to access the alpha database, and specify the outcomes of all pregnancies screened. Using alphaOutcome, you can produce summaries of pregnancies with specified abnormalities, and examine the uptake of different prenatal diagnostic procedures.

alphaOutcome is included as a standard feature of alpha version 7.0

Validation of risk screening for Down's syndrome

Studies have demonstrated (Wald NJ, Hackshaw AK, Huttly W, Kennard A. (1997) Empirical validation of risk screening for Down's syndrome. J Med Screen 3, 185-187, Wald NJ, Bestwick JP, Huttly WJ, Morris JK and George LM (2006) Validation plots in antenatal screening for Down’s syndrome J Med Screen 13 166-171) that risk estimates for Down's syndrome produced by alpha are accurate. The validation technique works by assigning each woman in the screened population to one of a number of predicted risk categories, chosen so that each category contains approximately the same number of cases of Down's syndrome. The mean predicted risk in each category is then compared to the prevalence of Down's syndrome among the women in the same category.

alphaOutcome enables alpha users to perform this validation for themselves, provided a sufficiently large number of women have been screened. This technique is a sufficient technical validation of a screening programme.

Click here to see a risk analysis report generated by Alpha which can be used to validate a screening program.  The diagonal line represents perfect agreement between predicted risk and prevalence.