Quick Entry
Joint-by-Joint Map
Enter the total count of tender and swollen joints across all 28 assessed joints. Use the joint map for a guided click-through if you prefer.
28 assessed joints: bilateral shoulders, elbows, wrists, MCPs (x5), PIPs (x5), knees. Hips and ankles are NOT included in the DAS28 count.
Click each joint to cycle through states: Tender only then Swollen only then Both then back to normal.
Bilateral Joints (Left / Right)
MCP Joints (metacarpophalangeal)
PIP Joints (proximal interphalangeal)
CRP Value
Enter CRP in mg/L (not mg/dL). If CRP is below the lab's detection limit, enter 0. Normal CRP is typically below 5 mg/L, though lab reference ranges vary.
Unit note: Most US labs report CRP in mg/L. If your lab reports in mg/dL, multiply by 10 before entering (e.g. 1.2 mg/dL = 12 mg/L).
📋 What This Calculator Does
The DAS28-CRP calculates a composite disease activity score for rheumatoid arthritis using four variables: the 28-joint tender count, 28-joint swollen count, patient global assessment on a visual analogue scale, and serum CRP. The result is a continuous score from 0 to 9.4 that places a patient into one of four activity states.
This version uses CRP as the inflammatory marker. The original DAS28 used ESR, but CRP has become preferred in most clinical settings because it is more responsive to short-term changes in inflammation and is less affected by non-inflammatory factors like age, anemia, and hypergammaglobulinemia.
🎯 When to Use This
Use the DAS28-CRP at every clinic visit in established RA patients. It is the standard tool for treat-to-target monitoring, the most common metric required for biologic drug approval in most health systems, and the primary outcome measure in the majority of RA clinical trials over the past 20 years.
It is most useful for tracking change over time in an individual patient rather than as a single snapshot. A patient with a score of 4.0 today compared to 5.8 three months ago has had a meaningful clinical improvement, even if 4.0 still represents moderate disease activity. The EULAR response criteria formalize this by combining the absolute score with the change from a previous visit.
One important limit: the DAS28 is a classification and monitoring tool for established RA. It is not a diagnostic tool and should not be used to establish the diagnosis.
📊 Interpreting the Score
| DAS28-CRP Score |
Activity State |
Clinical Meaning |
| < 2.6 |
Remission |
Target state for treat-to-target. Used for biologic tapering decisions. |
| 2.6 to 3.2 |
Low Activity |
Acceptable state if remission is not achievable. Monitor closely. |
| 3.2 to 5.1 |
Moderate Activity |
Consider escalating therapy. Most biologic eligibility thresholds fall here. |
| > 5.1 |
High Activity |
Active disease requiring treatment change. Elevated erosion risk. |
These thresholds were validated against radiographic progression and physical function outcomes. Wells et al., Ann Rheum Dis 2009.
💡 Pearls and Pitfalls
Clinical Pearls
✓
DAS28-CRP scores run about 0.6 points lower than DAS28-ESR on average in the same patient. This matters when comparing across visits if the inflammatory marker was switched, or when comparing your results to published biologic trial data, which mostly used ESR.
✓
The treat-to-target approach works. Multiple trials, including TICORA and BeSt, showed that using DAS28 to drive treatment decisions to a target of remission or low disease activity produced significantly better radiographic and functional outcomes compared to routine care. The score is only useful if you act on it.
✓
Track scores longitudinally. A single score is less informative than a trajectory. Persistent DAS28 above 3.2 over multiple visits is a stronger signal to change therapy than a single elevated reading.
Common Pitfalls
⚠
DAS28 remission does not equal ACR/EULAR Boolean remission. About 15% of patients who score below 2.6 on DAS28 still have two or more swollen joints. Some studies have reported patients in DAS28 "remission" with more than ten swollen joints. If your patient looks active clinically, trust your exam over the number.
⚠
The patient global assessment carries significant weight. A patient who rates their overall health as 90/100 due to fibromyalgia, depression, or osteoarthritis will push the DAS28 into moderate or high activity even with zero joint involvement. Always interpret the score in the context of why the patient global is elevated.
⚠
Hips, ankles, and feet are not counted. The 28-joint count excludes hips, ankles, and MTP joints. A patient with active ankle synovitis and hip arthritis can appear to be in low disease activity on DAS28 while having significant active disease. Consider supplementing with a clinical global assessment or musculoskeletal ultrasound when lower extremity disease is dominant.
⚠
CRP can be falsely normal in some patients. A subset of RA patients, particularly those with anti-CCP negative or seronegative disease, may have active synovitis with normal CRP. Do not assume disease is controlled based on CRP alone.
🔬 Evidence
The DAS28 was originally developed by Prevoo et al. in 1995 as a modification of the original 44-joint Disease Activity Score created by van der Heijde, van't Hof, and van Riel in 1990. The 28-joint version simplified data collection while maintaining validity.
The CRP-based version was developed and validated by Fransen and van Riel, published in Ann Rheum Dis 2003. Formal validation against radiographic progression and physical function outcomes was demonstrated by Wells et al. using data from two large abatacept RCTs, published in Ann Rheum Dis 2009. The remission threshold of 2.6 was validated against ACR preliminary remission criteria by Fransen et al. in 2004.
Important limitation on the DAS28-CRP thresholds: the standard cutoffs (2.6, 3.2, 5.1) were derived from DAS28-ESR data. Research by Diri et al. in 2020 showed that DAS28-CRP is systematically lower than DAS28-ESR by approximately 0.6 points, meaning the published thresholds may misclassify some patients when using the CRP version.
View References
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1
Prevoo ML, van 't Hof MA, Kuper HH, et al. Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum. 1995;38(1):44-48. Original DAS28 development paper.
2
Fransen J, van Riel PLCM. Development and validation of the DAS28 using CRP. Ann Rheum Dis. 2003;62(Suppl 1):10. Original CRP formula development.
3
Wells G, Becker JC, Teng J, et al. Validation of the 28-joint Disease Activity Score (DAS28) and EULAR response criteria based on CRP against disease progression in rheumatoid arthritis. Ann Rheum Dis. 2009;68(6):954-960. Validation against radiographic progression and HAQ-DI across EULAR responder states.
4
Fransen J, Creemers MCW, Van Riel PLCM. Remission in rheumatoid arthritis: agreement of the DAS28 with the ARA preliminary remission criteria. Rheumatology. 2004;43(10):1252-1255. Validation of the 2.6 remission threshold.
5
Diri E, Greenmyer J, Stacy J, et al. DAS28-CRP cutoffs for high disease activity and remission are lower than DAS28-ESR in rheumatoid arthritis. ACR Open Rheumatol. 2020;2(9):506-510. Documents systematic 0.6-point difference between CRP and ESR versions.
6
Smolen JS, Aletaha D, Bijlsma JWJ, et al. Treating rheumatoid arthritis to target: recommendations of an international task force. Ann Rheum Dis. 2010;69(4):631-637. Foundation paper for treat-to-target strategy using DAS28.