PSAT Study Guide (updated 2025)

The most common lab result in psoriatic arthritis? Normal. PsA is one of the few inflammatory arthritides where: • ESR and CRP can be normal • RF and anti-CCP are usually negative • Early X-rays may not show changes That’s why this is not a lab diagnosis. In rheumatology, the diagnosis comes from the pattern: history exam imaging when needed. This is also why so many people are told: “Your labs are fine” while the disease is still active. If your symptoms are inflammatory — morning stiffness, en