Can I specify which set of normal medians to use?

αlpha will normally calculate the expected marker level based on the regression equation coefficients in place on the date of the screening report. There may be cases when it is not correct to use the coefficients in place on this date. For example, when the first trimester markers in an Integrated test were assayed and the medians subsequently updated before the screening report was made, then the medians in place on the date when the measurement was taken should be used.

For cases such as this, αlpha provides the assay date field in the data entry screen. The assay date field is next to the field where the marker level is entered on the αlpha data entry screen. When a date is entered into the assay date field, αlpha will use the regression equation coefficients in place on that date, otherwise it will use those current at the time of issuing the screening report.