Omega Diagnostics believes it has identified a possible cause of reliability problems in its much anticipated HIV testing kit.

It said the stability issues of the Visitect CD4 system, which leads to more false positives, may be related to it being stored at ambient temperatures for longer periods.

Alva based Omega outlined how it is working to identify the component of the product, which offers a quick way to see whether retroviral drugs are needed without laboratory testing, that is causing the issue to occur.

The company said it was confident of resolving the problem but “the ultimate timing remains uncertain.”

It added: “We continue to believe that once the current technical challenges are resolved, Visitect CD4 will be competitively positioned to become a major success for the group.”

That came as it forecast an eight per cent rise in revenue to £6.15 million in the six months to September 30.

Underlying pre-tax profit is predicted to be similar to the £560,000 reported in the same period of 2014.

The revenue rise is being led by the food intolerance division which is expected to have grown around 20 per cent to £3.34m helped by increasing sales in the Americas, Middle East, Asia and the Far East.

The infectious disease division is on course to report a 13 per cent uplift to £1.22m but the allergy and autoimmune arm is forecast to be 13 per cent down to around £1.59m. That is said to be related to ongoing weakness in the German business along with unfavourable exchange rates.

On its allergy testing programme Omega said it now has 36 allergens that show equivalent performance to the market leading product.

An external evaluation of the Allersys technology has already been carried out in Spain with one in Italy starting this month. Further tests are scheduled to be conducted in Germany and France.

Analysts from Finncap said the “timing to commercialisation remains uncertain” on both CD4 and Allersys.

Omega’s fit-out of an additional manufacturing base in Pune, India has now been completed. While the site was slated to act as a secondary site to make CD4 kits it will also make other infectious disease tests. It will start working on a range of Malaria tests soon.