Background Procalcitonin (PCT), the calcitonin peptide precursor, is a new specific marker of severe bacterial and fungal infections. PCT is not or slightly elevated in others inflammatory diseases. PCT measurements could help to differentiate bacterial arthritis to other forms of acute arthritis.

Objectives To determine the interest of serum and synovial PCTfor the diagnosis of acute bacterial arthritis.

Methods

• A one year prospective study (RR study group): sera and synovial fluid from 32 adults with acute arthritis were immediately frozen (-20°C) before treatment. for all patients, the diagnosis was confirmed by specific synovial analysis.

• PCT (N < 0.5 mg) was measured by a specific and ultrasensitive immunoluminometric yesy (BRAHMS diagnostica, Berlin, Ger.)

ResultsResults are expressed in median and range. Values are compared between septic group and crystal or rheumatoid group by Mann-Whitney test: **p < 0.01; *p < 0.05.

Conclusion

• These results show that plasma PCT levels are higher in patients with septic arthritis, but PCT sensitivity remains unsufficient. However, in case of bacterial arthritis, PCT in association with CRP, could be of great interest for clinicians, as its increase is in favour of a bacterial origin.

• PCT is not present in all biological fluids. If synovial PCT does not seem to be helpful in clinical diagnosis, this study is, to our knowledge, the first to demonstrate PCT existence in synovial fluid.