Table 2: RF concentrations in synovial fluid prior to and following precipitation in patients SF1–SF5. SF1 was RF-negative, SF2–SF5 were RF-positive.

Synovial fluid sampleRFs prior to precipitation IU/mLRFs following precipitation IU/mLRFs in plasma from the same patient IU/mL

SF1217
SF234185
SF3291378
SF4541554
SF518960400