SERPINA4 and Sepsis: Day 1 and 3 kallistatin levels were also significantly lower in patients with septic shock compared with severe sepsis (day 1, p = 0.004 and day 3, p = 0.010) (Fig 2A) and in patients who had positive blood cultures versus negative blood cultures (day 1, p = 0.021 and day 3, p = 0.035) (Fig 2B).