PKD2^SSAA/SSAA mice display reduced thrombus formation in vitro but have normal tail-bleeding responses. Heparin/PPACK-anticoagulated blood from WT or PKD2^SSAA/SSAA mice was passed over collagen (shear rate 1000/s). (Ai) Representative phase-contrast images after 4 minutes of flow. Scale bars represent 20 μm. (ii) Platelet coverage of coated surfaces was quantified and the mean surface area ± standard error of the mean is shown for 3 independent experiments. *P < .05. (B) Mice were anesthetized and a transverse incision made with a scalpel at a position where the diameter of the tail was 2.25-2.5 mm. The tail was immersed in normal saline (37°C) in a hand-held test tube. The time from incision to cessation of bleeding was recorded, and mean times are shown as horizontal bars. No significant difference was seen comparing WT mice with PKD2^SSAA/SSAA mice (n = 10-14).