• Arterial blood pressure (BP) is most accurately measured invasively through an arterial line

• Invasive arterial pressure measurement with intravascular cannulae involves direct measurement of arterial pressure by placing a cannula needle in an artery (usually radial, femoral, dorsalis pedis or brachial)
• This is usually done by an anesthesiologist or surgeon in a hospital.

Aside from the white coat effect, arterial pressure readings outside of a clinical setting are ordinarily slightly lower Lower Blood Pressure in the majority of people. The studies that looked into the risks from hypertension and the benefits of lowering the arterial pressure in affected patients were based on readings in a clinical environment.