Blood Tests in Relation to the Coagulation Cascade

When I said the INR is insensitive to prothrombin activation, I meant that prothrombin cleavage tends to be localized to sites of endothelial activation in the blood vessels. Two people with identical prothrombin times ("bleeding times" that are reflected in the INR, which is the prothrombin time that's been normalized or standardized, to correct for variation between labs, etc.) can have drastically different risks of having some vascular event or having thrombogenic issues. If one site in a blood vessel is constricted or damaged, there can be localized activation of the coagulation cascade. The localized activation may produce generalized platelet activation or other evidence of pro-inflammatory changes, such as elevated fibrinogen or C-reactive protein concentrations or something, but those things may not show up on blood tests until there's some grave problem. The coagulation cascade can get going and still not produce any very obvious symptoms or even changes in blood tests.