PF4 and acute kidney injury: Specifically, PF4-positive patients had a higher adjusted OR of severe AKI in analyses assessing a composite of severe AKI or death (adjusted OR, 1.30 [95% CI, 1.00 to 1.70]), in analyses limited to patients who did not initiate KRT before the PF4 test (adjusted OR, 1.60 [95% CI, 1.03 to 2.49]), and in analyses limited to patients with a PF4 test performed in the first 10 days of hospitalization (adjusted OR, 1.71 [95% CI, 1.09 to 2.69]) (Figure 2).