Is the Alifax Test-1TH useful to determine the Disease Activity Score (DAS28) in rheumatoid arthritis patients?

Treatment of rheumatoid arthritis (RA) is monitored with the disease activity score (DAS28), for which the erythrocyte sedimentation rate (ESR) is needed. Apart from the original gold standard method, other methods like the Alifax Test-1TH apparatus are widely used in laboratory worldwide. We compared ESR values obtained by the Alifax Test-1Th apparatus and the gold standard method for 218 RA patients. We found a good correlation (r = 0.87) between the Alifax Test-1TH results and the gold standard method. A good correlation (r = 0.96) was also found for the DAS28 results obtained with both methods. The number of patients that were misclassified when the Alifax Test-1TH is used is reasonable for both the ESR (14.7%) and the DAS28 (10.6%). These results suggest that it may be useful to determine the ESR by the Alifax Test-1TH, with a DAS28 misclassification in less than 11% of the patients.