Synovial fluid sampling from the temporomandibular joint: sample quality criteria and levels of interleukin-1 beta and serotonin.

The aims of this study were to compare two sets of quality criteria (SQC A and B) with respect to synovial fluid (SF) sampling and to present temporomandibular joint (TMJ) SF levels of IL-1 beta and 5-HT. The study comprised 310 TMJ SF samples from 12 healthy individuals (HI) and 59 patients with TMJ inflammatory disorders. Ten HI and 37 patients were selected for investigation of TMJ SF levels and samples were obtained by a push-and-pull method with quantification by vitamin B12. The SQC comprised aspirate weight (AW), dilution factor (DF), blood contamination and hemolysis. IL-1 beta and 5-HT levels did not differ between the samples that satisfied SQC A or B. The proportion of samples that satisfied SQC A was higher than for SQC B. Patients with polyarthritides had significantly higher TMJ SF concentrations of 5-HT and IL-1 beta than HL. In conclusion, there is a recovery of TMJ SF of 0.1-0.2 g with the method used and the criteria set with the highest success rate do not differ from the other one with respect to SF levels of IL-1 beta and 5-HT. This set of sample quality criteria comprised no hemolysis, no or only minor blood contamination, AW > 0.5 g and DF < 0.98. The higher SF levels in the diseased TMJ (polyarthritides) compared to the healthy joint with respect to 5-HT and IL-1 beta is of clinical diagnostic relevance and the presence of 5-HT or IL-1 beta in TMJ SF seems to indicate a pathological joint condition probably of an inflammatory nature.