212867.fig.003
Figure 3: Percentage of PF value change in relation to the number of PF determinations. 2PF: two PF determinations. 3PF: three PF determinations. 4+PF: four or more PF determinations. The number of PF measurements is positively associated with the percentage of PF change ( 𝑟 = 0 . 3 5 7 , 𝑃 < 0 . 0 1 ) .