Shares in Omega, the Clackmannanshire-based medical diagnostics company, staged a welcome rally as the company confirmed an expected rise in profits and progress with its key new product.

The AIM-listed group focused on focused on allergy, food intolerance and infectious disease, has seen its shares halve in the past 12 months, hitting a sub-13p low this week. They rose 18per cent yesterday to close at 15.25p, valuing Omega at £16.3million.

The group has been frustrated by delays in its Visitect HIV-testing kit, which it believes could help transform HIV care in developing countries by providing a quick diagnosis of when retroviral drug treatment is needed.

Chairman David Evans said he recognised that Visitect was the major focus of investors' attention, adding: "The prospects for the group as a whole will be significantly enhanced by the success of this product." He said gaining access to a local hospital had significantly shortened testing times and Omega remained "very confident that we will resolve all of the issues previously reported".

Mr Evans said batch variability and long testing lead times had been corrected by internal investigations, more testing sites, and changes to the manufacturing process, which was now entirely in-house.

Omega said revenues for the year just ended were expected to be 4 per cent higher at £12.1m and adjusted profit before tax should be "significantly higher" at around £1.4m.

Testing revenues were up 15 per cent at £5.95m in food intolerance, up 4 per cent to £2.55m in infectious diseases, and down 9per cent to £3.61m in the allergy and autoimmune area.