This derived field contains the difference in days between the admission date (admidate) and the discharge date (epiend) provided the discharge method (dismeth) confirms that the spell has finished. If the episode has not finished it is calculated from the end of the year and admidate.

5n = Duration of spell in days from 0 to 29,200

null = Not applicable: patient not discharged (dismeth not in range 1-5), other maternity event (epitype is 5 or 6) or not valid