The laboratory aspect of the specialty means that most patients have some indirect contact with a haematologist. Laboratory and clinical advice is provided to a range of other professionals by letter, telephone or advice clinic, so that patients have the benefit of specialist advice through their usual healthcare provider.

Patients with haematological disorders can present to any healthcare professional so the referral pattern is wide. Most patients initially present to primary care, and are subsequently referred for specialist input. Others present through the hospital pathway, either as a result of their presenting condition, or a consequence of their illness or treatment. These patients are referred by other specialties.

A minority of patients are directed to services through laboratory services. Some patients with haematological disorders requiring emergency treatment (such as acute leukaemia, acquired haemophilia or thrombotic thrombocytopenic purpura) result in the laboratory triggering a pathway, resulting in a clinical review. Screening programmes for haemoglobin disorders (antenatal and newborn) may also trigger access to the service.

Due to the complex nature of some haematological disorders and the requirement for resource and expertise, some patients are referred from haematologist to haematologist. Examples include haemophilia and haemoglobinopathies, where there is an established network of accredited specialist centres which direct care. These networks operate as hub-and-spoke models, with some care delivered closer to home, and more specialist services within a specialist centre. It is not uncommon, due to the increasing subspecialisation within malignant haematology, for onward referral to be made to a subspecialist in a particular haematological cancer. Such a referral might be required for expertise or access to particular therapies (such as clinical trials or stem cell transplantation).