Evaluation of Prolonged PTT
Prolonged PTT Evaluation
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Dilution of patient's plasma with normal plasma followed by APTT and/or PT determination on the mixtures tested immediately and after 30 minute incubation at 37 C.
To determine reason for prolongation of the PT7 and/or aPTT test. Help to differentiate between a factor deficiency or coagulation inhibitor.
Physician interpretation included.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Collect specimen in two blue top (citrate 3.2%) tubes. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Alternatively, centrifuge, aliquot plasma into two plastic tubes, and freeze the specimen within 4 hours of collection. Transport frozen specimen on dry ice. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device), the line should be flushed with 5 mL of saline and the first 5 mL of blood or six dead space volumes of the VAD discarded.