These tubes contain an inert gel barrier and spray-dried lithium heparin additive . The inert barrier separates the plasma from the blood cells during centrifugation, preventing contamination of the plasma . For example, in plasma certain analytes such as potassium, phosphorus and glucose should be separated from the cells within a few hours, otherwise the results will be significantly impacted. Using BD PSTTM II tubes, routine analytes in clinical chemistry such as potassium are still stable after 24 hours storage at 2-8ºC . Clinical evaluation of special chemistries such as therapeutic drugs, proteins, peptides, steroids and vitamins demonstrates a high degree of stability within the BD PSTTM II1,2,3 .
BD Vacutainer® PSTTM II tubes enable faster centrifugation times of 5 minutes at 3000 g .
The main advantages of gel tubes versus non-gel tubes are:
Stable barrier between plasma and clotted blood during transportation and storage, therefore better analyte stability .
Better sample quality .
Optimisation of the work flow: short centrifugation time, sample processing and archiving in the primary tube .
No requirement for secondary tubes, reducing the possibility of misidentification.
Effects of temperature
BD Vacutainer® PSTTM II should be stored at 4-25°C and protected from direct sunlight during storage . Cooling of the tube by or during centrifugation can affect the movement . The optimum separation of sediment and plasma is achieved at a temperature of 20-25°C .
To avoid micro-clotting, mix the BD Vacutainer® PSTTM II tube with 8-10 inversions immediately after the blood sample has been taken .
1300-2000 g for 10 minutes at 18-25°C or alternatively, according to BD study VS 75134 3000 g for 5 minutes at 18-25°C.