how many days before an op do I need to go in for a pre op assesment
Report Abuse. Depending on the nature of your surgery, about a week before hand. Pre-op assessments for day surgery are valid for 6 weeks as long as there's no change in condition, and 4 weeks for in-patient. This is a national guideline.You should already have a date, which the nurse will confirm with you at your pre-assessment.eport Abuse. Depending on the nature of your surgery, about a week before hand. Pre-op assessments for day surgery are valid for 6 weeks as long as there's no change in condition, and 4 weeks for in-patient. This is a national guideline.