Azad said the government is also planning to buy cheaper chemicals used for testing influenza A virus from a German-based company.

Till now the government has been procuring the reagents and chemicals from the US firm Biosystem.

The health minister said each test costs a minimum of Rs.5,000, while for those that turned positive the test cost was Rs.10,000.

'It takes a minimum of six hours for a test to return positive,' he added.

Since May 16, when the first case was reported in Hyderabad, more than 4,000 people have been tested for influenza A (H1N1) virus. Of these, 840 people have tested positive, he added.