Prekallikrein Deficiency is a rare inherited blood disorder affecting dogs, including a Shih Tzu. Prekallikrein is a protein that is part of the blood clotting process, and when deficient, increases the time for blood to clot. The Shih Tzu reported with this condition did not show increased incidence of Hemorrhage however, recognizing a congenital cause for increased blood clotting times is important because it can be associated with clinically important diseases. Dogs with this disorder can have severe bleeding if they have concurrent deficiencies in other proteins required for normal blood clotting. Dogs with a bleeding disorder may bruise easily, have frequent nosebleeds and exhibit prolonged bleeding after surgery or trauma. Due to the mild nature of this disorder, affected dogs may not be identified until a surgery is performed or trauma occurs at which time excessive bleeding is noted. Veterinarians performing surgery on dogs that are known to have prekallikrein deficiency should have ready access to blood banked for transfusions. Most dogs with this condition will have a normal lifespan despite increased blood clotting times.