DAS28-ESR Calculator

Calculate DAS28-ESR with its four component contributions shown separately, and see exactly how far it diverges from DAS28-CRP in the same patient.

Last updated 18 Sep 2026

DAS28-ESR

4 inputs → activity score

Tender joint count (of 28)Shoulders, elbows, wrists, MCPs and PIPs of both hands, and both knees.

Swollen joint count (of 28)The same 28 joints. Feet and ankles are not in the count.

ESR (mm/h)The score takes the natural logarithm of the ESR, so it is undefined at 0. An ESR reported as 0 or <1 is conventionally entered as 1, or the 3-variable DAS28 is used instead.

Patient global health (0–100 mm VAS)0 is very well, 100 is very poor. This is the patient’s own mark, not the clinician’s.

4.89DAS28-ESRExample

Tender joint count 6, swollen joint count 4, ESR 28 mm/h, patient global health 45 mm

Formula

DAS28-ESR = 0.56√(TJC28) + 0.28√(SJC28) + 0.70·ln(ESR) + 0.014·GH

TJC28, SJC28: tender and swollen joint counts out of 28 — shoulders, elbows, wrists, MCPs and PIPs of both hands, and both knees
ESR: erythrocyte sedimentation rate in mm/h, entered as a natural logarithm, so the term is undefined at 0
GH: the patient’s own global health mark on a 0–100 mm visual analogue scale
Coefficients: 0.56, 0.28, 0.70 and 0.014 — the swollen joint count carries the smallest weight of the three clinical terms
DAS28-CRP: a different formula with a different constant: 0.56√TJC + 0.28√SJC + 0.36·ln(CRP+1) + 0.014·GH + 0.96

Worked example

Tender joint count 6, swollen joint count 4, ESR 28 mm/h, patient global health 45 mm
0.56 × √6 = 0.56 × 2.4495 = 1.37
0.28 × √4 = 0.28 × 2 = 0.56
0.70 × ln(28) = 0.70 × 3.3322 = 2.33
0.014 × 45 = 0.63
1.37 + 0.56 + 2.33 + 0.63 = 4.89 — moderate disease activity
The ESR term alone supplies 2.33 of the 4.89 — nearly half the score from one variable
The same patient with a CRP of 18 mg/L scores 4.58 on DAS28-CRP, a gap of 0.31

DAS28-ESR and DAS28-CRP activity bands side by side

The middle column is what almost every calculator and registry does — carry the ESR-derived bands straight over to the CRP score. The right-hand column is what the studies that actually re-derived them found. Note that the three CRP high-activity figures do not agree with each other either, which is why this page prints all three with their cohorts rather than an average.
Activity	DAS28-ESR	DAS28-CRP as usually applied	What the published CRP data actually give
Remission	< 2.6	< 2.6	2.3 (Inoue, Japanese cohort)
Low activity	2.6 – 3.2	2.6 – 3.2	2.7 (Inoue)
Moderate activity	> 3.2 to 5.1	> 3.2 to 5.1	— no separately derived band
High activity	> 5.1	> 5.1	> 4.06 (Greenmyer, n = 171); > 4.1 (Inoue); > 4.6 (Fleischmann, n = 834)

How big is the gap between the two scores?

Every published comparison puts DAS28-CRP lower, but the size ranges from 0.3 to 0.7 depending on the population — enough to move a patient a whole band. Fleischmann found that using the 5.1 cut-off on CRP classified 69.0% of one trial arm as high activity where the ESR score classified 85.1%.
Study	Population	Mean DAS28-ESR − DAS28-CRP
Hensor et al, Rheumatology 2019	UK cohort, all patients	0.30 (0.35 in women and in patients over 50)
Fleischmann et al, RMD Open 2017	COMET and PRIZE early-RA trial data, n = 834	≈ 0.55
Matsui et al, Ann Rheum Dis 2007	Japanese observational cohort, n = 3,073	0.72 (mean 4.31 against 3.59)

Why the ESR term behaves the way it does

Because the term is logarithmic, every doubling of the ESR adds the same 0.48 — so the move from 5 to 10 mm/h costs as much score as the move from 40 to 80. At low joint counts this single variable can dominate the total, which is what the component breakdown above the result is there to show.
ESR (mm/h)	0.70 × ln(ESR)	Change from the row above
5	1.13	—
10	1.61	+0.48
20	2.10	+0.48
40	2.58	+0.48
80	3.07	+0.48
120	3.35	+0.28

One patient, two scores, and which thresholds were actually derived

DAS28-ESR is the original of the pair. The DAS28 was developed and validated using the ESR, and the activity thresholds everyone quotes — remission below 2.6, low activity to 3.2, high activity above 5.1 — belong to that version. DAS28-CRP came later, derived by fitting a CRP-based formula against the ESR-based one in a cohort of 334 patients, and it arrived with a different constant term and a different coefficient on the inflammatory marker. What it did not arrive with is its own set of thresholds. As Hensor and colleagues put it, “ACR and EULAR do not differentiate between the two versions of the score when using disease activity thresholds” — so the ESR bands were simply carried across.

That would not matter if the two scores agreed. They do not. Every published comparison finds DAS28-CRP systematically lower: by 0.30 points in a UK cohort, by about 0.55 in pooled early-RA trial data, and by 0.72 in a Japanese observational cohort of 3,073 patients, where the mean DAS28-ESR was 4.31 and the mean DAS28-CRP 3.59. The clinical consequence is exactly what it sounds like: the same patient, measured on the same day, can be in remission on one score and not on the other, or below the high-activity line on one and above it on the other. Matsui and colleagues concluded that DAS28-CRP “significantly underestimated disease activity and overestimated the improvement in disease activity compared with DAS28-ESR” — which matters most where the score gates access to a biologic, because a patient can fail to qualify on the wrong instrument.

Three groups have tried to re-derive the high-activity threshold for CRP, and the honest summary is that they disagree. Inoue and colleagues found DAS28-CRP values of 2.3, 2.7 and 4.1 corresponding to the ESR score’s 2.6, 3.2 and 5.1, with the explicit caveat that their results came “from only Japanese patients”. Greenmyer and colleagues found 4.06 in 171 newly diagnosed American patients, with 33.9% discordance between the two scores. Fleischmann and colleagues, using pooled data from the COMET and PRIZE trials, found 4.6 and recommended it directly. So the CRP equivalent of 5.1 is somewhere between 4.06 and 4.6 depending on whose cohort you trust — and that uncertainty is itself the argument for picking one instrument per patient and tracking it, rather than switching between them. This site keeps the two as separate pages for that reason; the DAS28-CRP page covers the joints the 28-joint count omits and the way coexisting fibromyalgia inflates both scores.

The component breakdown printed beside the result exists because of the logarithm. The ESR enters as 0.70 × ln(ESR), so it climbs steeply from low values and then flattens: going from 5 to 10 mm/h adds 0.48, and so does going from 40 to 80. In a patient with few tender or swollen joints, that single term can supply most of the score — and the ESR is the least specific of the four inputs, moving with age, sex, anaemia, pregnancy, paraproteins and infection rather than with synovitis. If your patient is older, the age-adjusted ESR upper limit is worth checking before reading a raised ESR as active disease. And the 28-joint count excludes the feet and ankles entirely, so a patient whose disease is confined to the forefoot can score low on either version. This supports a clinician’s judgement rather than replacing it. It is arithmetic on the figures entered, and it knows nothing about the patient in front of you.

Frequently asked questions

What is the DAS28-ESR formula?

DAS28-ESR = 0.56 × √(tender joint count of 28) + 0.28 × √(swollen joint count of 28) + 0.70 × ln(ESR in mm/h) + 0.014 × patient global health on a 0–100 mm scale. There is no constant term — that is the DAS28-CRP formula, which adds 0.96.

Why is DAS28-CRP lower than DAS28-ESR?

Because the CRP formula was fitted to approximate the ESR one rather than derived independently, and the approximation is biased downward. Published mean differences are 0.30 in a UK cohort, about 0.55 in pooled early-RA trial data, and 0.72 in a Japanese cohort of 3,073 patients. The same patient can therefore be in remission on CRP and not on ESR.

Can DAS28-ESR thresholds be used on a DAS28-CRP score?

They are, universally, and they probably should not be. The 2.6, 3.2 and 5.1 thresholds were derived on the ESR version. Studies that re-derived the high-activity threshold for CRP found 4.06, 4.1 and 4.6 — all well below 5.1 — so applying 5.1 to a CRP score under-calls high disease activity.

What if the ESR is reported as 0?

The formula takes ln(ESR), which is undefined at 0, so a zero cannot be entered. The usual conventions are to enter 1, or to use the three-variable DAS28, which omits the patient global health term and rescales. This calculator has a minimum of 1 mm/h.

Which joints are in the 28-joint count?

Shoulders, elbows, wrists, metacarpophalangeal and proximal interphalangeal joints of both hands, and both knees. The feet and ankles are excluded, which is the count’s best-known blind spot — active forefoot disease does not register.

How does DAS28 remission differ from ACR/EULAR Boolean remission?

DAS28 remission is simply a score below 2.6. Boolean remission requires the tender joint count, swollen joint count, CRP in mg/dL and patient global assessment each to be 1 or less. A patient can meet the DAS28 definition with a swollen joint present, because the swollen joint count carries the smallest of the three clinical coefficients.

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References

Prevoo MLL, 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):44–8.
van Gestel AM, Prevoo MLL, van ‘t Hof MA, et al. Development and validation of the European League Against Rheumatism response criteria for rheumatoid arthritis. Arthritis Rheum. 1996;39(1):34–40.
Fransen J, van Riel PLCM. The Disease Activity Score and the EULAR response criteria. Clin Exp Rheumatol. 2005;23(5 Suppl 39):S93–9.
Fleischmann R, van der Heijde D, Gardiner PV, et al. DAS28-CRP and DAS28-ESR cut-offs for high disease activity in rheumatoid arthritis are not interchangeable. RMD Open. 2017;3(1):e000382.
Matsui T, Kuga Y, Kaneko A, et al. Disease Activity Score 28 (DAS28) using C-reactive protein underestimates disease activity and overestimates EULAR response criteria compared with DAS28 using erythrocyte sedimentation rate in a large observational cohort of rheumatoid arthritis patients in Japan. Ann Rheum Dis. 2007;66(9):1221–6.
Inoue E, Yamanaka H, Hara M, Tomatsu T, Kamatani N. Comparison of Disease Activity Score (DAS)28-erythrocyte sedimentation rate and DAS28-C-reactive protein threshold values. Ann Rheum Dis. 2007;66(3):407–9.
Hensor EMA, Emery P, Bingham SJ, Conaghan PG. Gender stratified adjustment of the DAS28-CRP improves inter-score agreement with the DAS28-ESR in rheumatoid arthritis. Rheumatology (Oxford). 2019;58(5):831–8.
Greenmyer JR, Stacy JM, Sahmoun AE, Beal JR, Diri E. DAS28-CRP cutoffs for high disease activity and remission are lower than DAS28-ESR in rheumatoid arthritis. ACR Open Rheumatol. 2020;2(9):507–11.

Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.