Pathology All are true about blood coagulation except? A Intrinsic pathway can be activated in vitro. B Extrinsic pathway is activated by contact of plasma with negatively charged surfaces. C Calcium is very important for coagulation. D Factor X is a part of both intrinsic and extrinsic pathway. 💡 Explanation All are true about blood coagulation except? ✓ Correct Answer: D. Factor X is a part of both intrinsic and extrinsic pathway.