Categorization / classification pattern

This question may be a bit too generic and abstract because I do not know what I'm looking for yet. I do not have too much experience with patterns. I need to know what pattern/ technique I can use to categorize patients in a medical app.

Let's say the hospital has a documentation app with 10 data fields. Dates, numbers, selects, multi-selects. Every patient that visits the hospital will have it's own specific information. After input and analysis, each patient must be placed in a category. Each category is determined by a set of rules. Those rules are created based on some or all fields defined above and their individual value.

In reality I'm speaking about hundreds of patients and hundreds of input fields. So I'm trying to find out whether there is some traditional way of doing this (something more generic) or if I'm stuck with writing tens of "IF and Switch" statements.

PS: this is not a machine learning task Thank you all in advance!