Need to filter out blank end dates in measure

[ArchStanton]

I have the following measure below that works but I need to modify it so it excludes any 'Closed' dates thatb are blank.

Cases Deferred YTD = 
                (TOTALYTD(COUNTA('Cases'[Total Deferrals]),
                'Cases'[createdon],
                "31/3"))

Any ideas how to do this? Everything I attempt doesn't work because intellisense only shows me other measures, whereas I need to filter out Blanks from another column.

The Column name is called Closed and its from the same Cases table.

Thanks

[johnt75 · Accepted solution]

Try

Cases Deferred YTD =
(
    TOTALYTD (
        COUNTA ( 'Cases'[Total Deferrals] ),
        'Cases'[createdon],
        NOT ISBLANK ( 'Cases'[Closed] ),
        "31/3"
    )
)

[ArchStanton]

Perfect, thank you so much!!!!