The first over-the-counter DIY testing kit for HIV is expected to go on sale in America in the next month. It's said to allow people to screen potential sexual partners for HIV before deciding to have sex them - all in the comfort of their own home. But sexual health consultant from London's Chelsea and Westminster hospital Ann Sullivan believes that the idea is flawed as someone could be recently infected and still show a negative result. Her hospital offers an HIV test to all patients who are admitted to the Emergency Department. A positive result is picked up in around 4 people in every thousand tested. Glasgow GP Dr Margaret McCartney analyses the latest HIV figures for the UK - which are on the rise. She advises that safe sex should be practised even with a negative result to help protect people from all sexually transmitted infections.

Vitamin D and TB

As much of the UK enjoys the last of the summer sun, Vitamin D is back in the headlines. The body makes its own Vitamin D with sun exposure - but supplements in tablet form can be taken by anyone who's deficient. A dose of the Vitamin D was given to patients with tuberculosis - along with the regular antibiotics - and it helped to speed up their recovery. Dr Adrian Martineau, who's a Senior Lecturer in Respiratory Infection and Immunity at Queen Mary University, London, says that the Victorian idea of giving "consumptive" patients of sunshine was spot on.

Vitamin B12

A growing number of people believe they're deficient in another Vitamin - B12. Sources of the vitamin include meat, fish and dairy products - so strict vegans can be at risk of deficiency. The vitamin is crucial in the production of red blood red cells and for the normal functioning of the brain and nervous tissue. Symptoms of low levels can include anaemia, tiredness, pins and needles, memory loss and confusion. If it's not addressed promptly the damage can be irreversible. John Hunter who's Professor of Medicine at Cranfield University sees many patients who can't absorb the vitamin because of problems with their gut like Crohn's or Coeliac disease. Another condition - pernicious anaemia - is caused by the lack of a protein required to make absorption possible. As many as 1 in 30 adults have B12 deficiency - rising to 1 in 16 in the over 65s. A blood test which is used to check levels is thought by many doctors and patients to be inaccurate. The top-up injections of B12 are usually given every 2 or 3 months, in spite of many patients saying that their symptoms return well before their next one is due. Martyn Hooper from the Pernicious Anaemia Society says that testing and treatments need to be improved - to stop patients resorting to their own drastic solutions outside mainstream medicine.

Mouth Ulcers

One in 5 of the UK population will get mouth ulcers at some stage of their lives. For some, they can recur every month or so - in painful crops that can take a fortnight to heal. Some are associated with underlying problems such as inflammatory bowel disease, or vitamin and mineral deficiencies, but in many cases no cause is found.

Patients like Ruth have to avoid certain foods - like chocolate and fruit - to reduce the risk of recurrence. She's had ulcers since her teens and now takes immunosuppressant drugs to reduce their impact on her life. Tim Hodgson who's a consultant in oral medicine at the Eastman Dental Institute in London has had some success treating them with drugs like thalidomide. He says that some patients fear that their recurrent ulcers could develop into oral cancer - but that simply isn't the case.