Here is the final code solution that was implemented and appears to be working:
Function dtComprRtrn(ByVal awardField As String, ByVal suspendField As String, ByVal chkDtField As String) As Boolean
If chkDtField Is Nothing Then
Return True
End If
Dim compareDate As Date = DateTime.MinValue
Dim chkDtDate As Date = DateTime.MinValue
' Check to see if input string chkDtField is a date
If (IsDate(chkDtField)) Then
chkDtDate = Convert.ToDateTime(chkDtField)
End If
' Check to see if either awardField or suspendField is a date
' if not then return false
If (IsDate(awardField)) Then
compareDate = Convert.ToDateTime(awardField)
ElseIf (IsDate(suspendField)) Then
compareDate = Convert.ToDateTime(suspendField)
Else
Return False
End If
' Now we know we have a date in compareDate
' and we know that chkDtDate is at least DateTime.MinValue
' so if chkFtField was blank then this comparison will always
' work if we have a valid date for awardField or suspendField
If compareDate >= chkDtDate Then
Return True
Else
Return False
End If
End Function