IF Statement with multiple conditions and an overriding value

Thanks in advance for helping with this. I have an issue where this I need the following formula to calculate this- i would advise seeing the picture in the link to fully understand the question (as I'm probably not going to explain myself!);

Calculating Risk Score

Condition 1: If Blood Result is less <=9 or Score <=6 or Tumour Size = <5mm show as text value Low

Condition 2 : If Blood Result 10-20 or Score = 7 or Tumour Size 5mm-9mm show as text value Medium

Condition 3: If Blood Result >=20 or Score = 8 or Tumour Size >=10mm show as text value High

The issue I am having is that any person can have a value from any of the condition, but I need to display the overriding value.

Example:

Blood Result = 5 (condition 1)

Score = 7 (condition 2)

Tumour Size = 10mm (condition 3)

SHOW VALUE: HIGH.

The problemn i'm having is that when I'm doing IF statements, as condition 1 of blood result is True, its always displaying Low without looking at the other values which could overwrite it.

I have only tried nested IF statements with AND OR in them, but no luck.

See examples of values