What Is a PsARC Exam?

Psoriatic arthritis (PsA) is a complex disease. The symptoms – which can include joint pain, inflammation, and swelling of the fingers and toes – vary from person to person. The Psoriatic Arthritis Response Criteria (PsARC) is a tool used to evaluate and monitor PsA.¹

A tool to measure disease activity

There are several types of PsA. They consist of various symptoms and occur in different areas of the body. It can be a hard disease to diagnose.¹

For that reason, a more standardized approach to understanding the disease was needed. In 1996, the PsARC was created to help measure disease activity in people with PsA. It also measures any changes in the disease that might need different treatment methods.²

What does the PsARC measure?

A PsARC exam consists of a physical exam and assessments made by a person with PsA and their doctor. These assessments are divided into 4 categories. The categories analyze different aspects of PsA, including:²

• Joint tenderness
• Joint swelling
• A person’s opinion on their overall health
• A doctor’s opinion of a person’s overall health

During the physical exam, a doctor examines the joints on the body for tenderness and swelling. This evaluation is referred to as a 66/68 Joint Count. It evaluates 66 joints for swelling and 68 joints for tenderness and pain with movement.

For tenderness, joints that are examined include hands, wrists, feet, elbows, shoulders, hips, and knees.

Additional considerations: Another aspect of the PsARC exam is for the person to assess their health and answer questions like, “Considering how your arthritis affects you, how are you feeling today?”

Each question receives a numbered rating using the Likert Scale, with 1 being “very good, no symptoms” and 5 being “very poor, severe symptoms.”²

Before the PsARC, what was used to assess PsA?

In the past, clinical tools used to measure PsA were adopted from tools used for other rheumatoid diseases, like rheumatoid arthritis (RA). This is because many of the signs and symptoms of PsA are similar to RA.²

One of the past tools used to assess PsA was the Disease Activity Score (DAS). The DAS measures RA disease activity. It combines information from:²

• Swollen joints
• Tender joints
• Acute phase response (which happens during a flare-up)
• The person’s self-report of general health

What are the similarities and differences between the PsARC and DAS?

A key difference between the PsARC exam is that it assesses more joint activity than the DAS. In the DAS, 28 joints are assessed. Similarities of the PsARC and DAS include assessments of:^2,3

• Number of tender joints
• Number of swollen joints
• Person’s assessment of their general health
• Doctor’s assessment of a person’s general health

In the PsARC exam, 68 tender and 66 swollen joints are evaluated.^2,3 Using the DAS for people with PsA can be limiting. It may not provide enough information to recommend the most appropriate treatment.²

Tools to measure PsA continue to evolve

Reasons for PsA are not exactly known. Research continues to evolve to understand the disease’s progression and its impact on people’s physical health and quality of life.¹

There are now more tools than ever – in the form of assessments, surveys, and questionnaires – that seek to understand how PsA affects each person. In the last several years, 2 new PsA-specific measures of disease activity were created. These are the Psoriatic Arthritis Joint Activity Index (PsAJAI) and Disease Activity in Psoriatic Arthritis (DAPSA).

And there continue to be others. Regular PsA assessments are crucial in treating the disease and helping people achieve remission. The more disease-specific assessment tools there are, the greater impact they may have on treatment options and a person’s overall quality of life.³