Rheumatoid Arthritis Severity Score Calculator

What is the Rheumatoid Arthritis Severity Score (RASS)?

The Rheumatoid Arthritis Severity Score (RASS) is a quantitative tool used to assess the severity of rheumatoid arthritis (RA). By evaluating joint tenderness, swelling, patient-reported outcomes, and physician evaluation, RASS provides a comprehensive measure of disease activity.

Why is RASS Important?

RASS helps monitor disease progression, guide treatment decisions, and evaluate the effectiveness of therapeutic interventions. Tracking severity is essential for improving patient outcomes and achieving better quality of life.

How is RASS Calculated?

RASS is calculated by summing scores from the following components:

• Tender Joint Count: Number of tender joints.
• Swollen Joint Count: Number of swollen joints.
• Patient-Reported Outcome: Scored from 0 (very well) to 10 (very poor).
• Physician's Medical Opinion: Scored similarly to patient outcome, from 0 to 10.

The total severity score is computed as:

Total Severity Score = 
Tender Joint Count + Swollen Joint Count +
Patient Outcome (pts.) + Physician Evaluation (pts.)

Example Calculation

Inputs:
  Tender Joint Count: 3
  Swollen Joint Count: 2
  Patient-Reported Outcome: 6 (2.5 pts.)
  Physician's Opinion: 8 (3.5 pts.)

Calculation:
  Total Severity Score = 
  3 + 2 + 2.5 + 3.5 = 11

Result:
  Severity Category = Moderate

Severity Categories

The severity score is classified into the following categories:

• Mild: Score < 10
• Moderate: Score 10–20
• Severe: Score > 20

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