All of these programmes use a stable whole blood material. The samples you will receive are stabilised using a patented procedure and will remain stable up to 1 year at between +2 and +8 degrees C. Please store any samples at this temperature until testing but allow the samples to reach ambient temperature before staining.
Because the material is stabilised some minor adjustments may be required to the Forward Scatter (FSc) and Side Scatter (SSc) Photo Multiplier Tube (PMT) voltages. This is normal and does not affect the staining characteristics. Owing to the stabilisation process, the cells are not viable. UK NEQAS LI therefore recommends that viability dyes are either not used or, if used, all cells are included in the viable cells gate. In addition, the stabilisation process allows for haemoglobin to leach out of the red blood cells. As a result of this the samples may have a haemolysed appearance. This is normal and the samples can be tested.
Do not be concerned if the haematology profile on these samples does not give a valid differential. This is due to the stabilisation process. These samples have been developed to give the optimum performance using “flow cytometric” assays and have been used in these EQA programmes for over fifteen years.