Changes

===Laboratory Tests===

===Laboratory Tests===

Coagulation screening tests are unlikely to reveal abnormalities

Laboratory tests are unlikely to show abnormalities until 36-72 hours after exposure, due to the delay in onset of haemorrhagic signs. Because factor VII, involved in the extrinsic pathway, has the shortest half-life prothrombin time is generally the first parameter to become prolonged as factor VII is depleted most rapidly.

until at least 36 to 72 hours post-exposure. The

and is therefore the

first (by 36 to 48 hours), since F-VII, a component of the

tissue factor-mediated coagulation pathway, has the

shortest half-life (about six hours) and is therefore the

first factor to become depleted. The partial thromboplastin

first factor to become depleted. The partial thromboplastin

time (PTT) and activated clotting time (ACT) are

time (PTT) and activated clotting time (ACT) are