The major national and global policies relevant to public health are continuously changing.There is a continuous cycle of change based on the political party in control at any time, the financial climate, key actors involved in lobbying, public opinion and many more.(See Health Policy section 4c). When thinking about this however, it is helpful to take the broadest possible view possible and remember the wider determinants of health. The World Health Organisation has a useful interactive site with a plethora of useful policies ranging from Antimicrobial resistance to dementia.The UK Government regularly produces a range of policies relating to public health including transport, health and education.The devolved administrations across the UK also produce National policies and plans, all of these will need consideration.

21 1. Please explain the term Coombs' positive (direct and indirect) and negative haemolytic anaemia. 2. What are the principles of the Coombs' test?

22 How often is Aldomet (alpha methyldopa) associated with autoimmune haemolytic anaemia or hepatitis? Is a normal person, with a positive Coombs' test owing to previous treatment with this drug, safe to donate blood?

23 What is the mechanism of priapism in sickle-cell anaemia?

24 Is sickle-cell disease associated with any of the glomerular disorders?

25 What is the acute chest syndrome?

26 Patients with thalassaemia intermedia have recurrent leg ulcers and recurrent infections. What is the mechanism of this?

27 What is the mechanism of iron absorption from iron polymaltose complex and carbonyl iron?

28 Iron overload in patients with thalassaemia major should be checked by measuring the serum ferritin and hepatic iron stores. How are the hepatic iron stores measured? By liver biopsy? And does not the measurement of serum ferritin suffice?

29 In the investigation for paroxysmal nocturnal haemoglobinuria (PNH), are the sucrose haemolysis test and Ham's acid serum test commonly done? What are the principles behind these tests?

30 Why isn't the blood of polycythaemia vera patients, after repeated phlebotomies, used for transfusion purposes? Although it is a premalignant condition, the red cells do not contain a nucleus and thus transfusion of only pure red blood cells (RBCs) would be a great benefit.