| Description: |
Plasma with a prolonged Prothrombin Time is mixed with normal plasma and a Prothrombin Time is performed. An inhibitor of the Prothrombin system is indicated if the Prothrombin Time is not corrected with the addition of the normal plasma. Prolongation of the PT may be due to either factor deficiencies or a circulating inhibitor (usually an antibody). In the case of a factor deficiency, the 1:1 mix of patient and normal should show correction of the PT equal to or less than the 1:1 mix of the normal and buffer. An inhibitor will prolong the 1:1 mix of the patient and normal compared to the 1:1 mix of the normal and buffer. If the factor concentrations are adequate, the 1:1 mix of patient and buffer may have a shorter clotting time than the original patient specimen because the inhibitor has been diluted. |
