A method for counting monosodium urate crystals in synovial fluid

Submitted: 5 May 2015
Accepted: 18 June 2015
Published: 30 June 2015
Abstract Views: 1814
PDF: 898
Publisher's note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.


This study was aimed to standardize the technique for counting monosodium urate (MSU) crystals in the synovial fluid (SF) of patients with gout. A total of 52 SF specimens were examined under a polarized light microscope. The amount of SF ranged between 0.1 and 45 mL (median 3 mL). MSU crystals were counted in four areas with the same size at 400x magnification. Cytological examination of the same specimens was also performed. Median leukocyte count was 400 cells/mm3 (range 50-14,000 cells/mm3), with a median percentage of polymorphonuclear leukocytes of 9% (range 0%-98%). Median crystal count was 179.5 (range 3-1600). Inter- reader and intra-reader agreement in crystal counting were good with a weighed k of 0.89 [95% confidence interval (CI) 0.85-0.94] and 0.89 (95% CI 0.84-0.93), respectively. Our data indicate that the SF MSU crystal count is a feasible and highly reliable technique.



PlumX Metrics


Download data is not yet available.


How to Cite

Montagna, P., Brizzolara, R., Ferrone, C., Cutolo, M., Paolino, S., & Cimmino, M. (2015). A method for counting monosodium urate crystals in synovial fluid. Reumatismo, 67(1), 29–32. https://doi.org/10.4081/reumatismo.2015.827