Store at 4 degree C or -20 degree C. The working antibody solution is stable for at least 7 days at 4 degree C. Precautions should be taken for storage for longer periods. Problems of long term stability may occur with highly diluted solutions. No other preservative agent has been added to the present formulation. For long storage purposes in solution the addition of sodium azide to 0.02 % is advised with the appropriate precautions of use.