In order to obtain serum samples from plastic tubes, the tube must have a coagulation activator added. As the plastic surface alone is insufficient to trigger the coagulation within an acceptable time, BD Vacutainer® Plus plastic serum tubes have silica particles added for this purpose. These tubes are marked with the acronym CAT (Clot Activator Tube).
The recommended minimum time for the coagulation of samples from patients who have not been treated with anticoagulants is 60 minutes for serum (red) and 5 minutes for thrombin (orange) tubes.
≤ 1200 g for 10 minutes at 18-25°C for glass serum tubes
≤ 1300 g for 10 minutes at 18-25°C for plastic serum tubes
Both plastic and glass serum tubes should be gently inverted 180° and back 5-6 times.