A blood sampling transfer device that is adapted to receive a blood sample having a cellular portion and a plasma portion is disclosed. The blood sampling transfer device is able to separate the plasma portion from the cellular portion. After separation, the blood sampling transfer device is able to transfer the plasma portion of the blood sample to a point-of-care testing device. The blood sampling transfer device also provides a closed sampling and transfer system that reduces the exposure of a blood sample and provides fast mixing of a blood sample with a sample stabilizer. The blood sampling transfer device is engageable with a blood testing device for closed transfer of a portion of the plasma portion from the blood sampling transfer device to the blood testing device. The blood testing device is adapted to receive the plasma portion to analyze the blood sample and obtain test results.