DVT is a medical condition that occurs when a blood clot forms in a deep vein. These clots usually develop in the lower leg, thigh, or pelvis, but they can also occur in the arm.. Anything that prevents your blood from flowing or clotting normally can cause a blood clot. The main causes of DVT are damage to a vein from surgery or trauma and inflammation due to infection or injury .DVT can be very serious because blood clots in your veins can break loose, travel through your bloodstream and get stuck in your lungs. This is called a pulmonary embolism. A pulmonary embolism can be life threatening and needs treatment straight away. 2 mL (1 mL min.) Serum from 1 SST AND 6 mL Whole blood in 2 Blue Top (Sodium Citrate) tubes. Mix thoroughly by inversion. Transport to Lab within 4 hours. If this is not possible make PPP within 1 hour of collection as follows: Centrifuge sample at 3600 rpm for 15 min. & transfer supernatant to a clean plastic tube. Centrifuge this supernatant again at 3600 rpm for 15 mins. & finally transfer the supernatant (PPP) to 1 labelled, clean plastic screw capped vial. FREEZE IMMEDIATELY. Ship frozen. DO NOT THAW.