is this white cell count is considered to be very low?

My son has had a low white blood cell count for the past few months which was picked up after he was poorly a few times with very bad tummy pains. It was thought at first that he had appendicitis but this turned out not to be the case. He then had blood tests which revealed his low white blood cell count. His reading has been at around 1.1 and 1.5 over a period of around 4 months. He gets very bad tummy pains every few weeks and a temperature. He has also over the last little while had some mouth ulcers. Apart from that he is generally well, albeit struggling to maintain his sporting achievements of the past. Our doctor is now referring him to a haematologist for further investigation. I would like to know if this white cell count is considered to be very low, if anything can be done about it and also what we might expect from the haematologist appointment? Many thanks.