Table 1: RF concentrations in the plasma samples prior to and following precipitation in patients 1–5 (P1–5). P1 is RF-negative, the rest are RF-positive.

Plasma sample RFs prior to precipitation IU/mL RFs following precipitation IU/mL P1 4 5 P2 25 12 P3 195 85 P4 236 118 P5 1141 631