This is the cookie-cutter flaw of confusing necessary and sufficient conditions. The doctor doesn’t make this mistake; her argument relies on causal logic, not conditional logic.

The doctor’s argument is flawed because she assumes that angiotensinogen levels cause high blood pressure, not because she overlooks other factors that might counteract the effects of disease X.

In order to conclude that disease X causes high blood pressure by raising angiotensinogen levels, the doctor must assume that high angiotensinogen levels cause high blood pressure. However, her argument only establishes that the two are correlated.

The only proven causal connection in the argument is that disease X usually causes higher angiotensinogen levels. The doctor doesn’t confuse this by saying that higher angiotensinogen levels cause disease X. Instead, she assumes that they cause high blood pressure.

This is descriptively inaccurate. The doctor says one phenomenon (disease X) causes a second phenomenon (higher angiotensinogen) and assumes that higher angiotensinogen causes high blood pressure. She then concludes that disease X is the immediate cause of high blood pressure.