Quantitative alpha-defensin testing: Is synovial fluid dilution important?

Figure 1 Results of alpha-defensin concentration (mg/L) according to each dilution. A: 1:10; B: 1:100; C: 1:500; D: 1: 1000; and E: 1:5000. Noteworthy, for infected cases a gradual increase in the sample dilution resulted in an increasing level of alpha-defensin. The same was not observed in the aseptic cases. In addition, both 1:1000 and 1:5000 dilutions presented favorable results to differentiate infected and aseptic cases.

Figure 2 Results of synovial fluid alpha-defensin values of all patients using 1:1000 and 1:5000 dilution. A: 1:1000 dilution; B: 1:5000 dilution. As observed, there was one case of false negative in the infected group.