Every fifth person who underwent a test for influenza H1N1 since April in the city has tested positive for the virus. The wide footprint of swine flu becomes clearer given that only a fraction of H1N1 patients - those hospitalized or belonging to the high-risk groups - are being tested according to the government protocol.Health experts say H1N1 has been the most dominant influenza type this monsoon.Data compiled by the BMC showed that of the 2,603 people tested for the infection since April, 484 were positive. Maharashtra, including Mumbai, recorded 284 deaths and 2,324 cases this year, and continues to be one of the worst-affected states. The city has had nearly 500 confirmed cases and nine deaths so far.Interestingly, the positivity rates seem to differ between public and government testing laboratories. In the public laboratories such as Kasturba and Haffkine Institute, the positivity rate is higher at around 23%. The rate drops significantly to 17% in the private laboratories. Currently, 11 laboratories and private hospitals in the city are permitted to carry out H1N1 tests.“The difference in positivity is because of sampling. At public hospitals, appropriate sampling techniques are followed, whereby specimens from only serious or hospitalized patients are being tested. Private centres, on the other hand, are not abiding by the government protocol and testing even those who don't need to get tested,“ said a senior civic official.He added that this not only puts a burden on the labs but also unnecessarily taxes the patient. The H1N1 test costs Rs 4,500 in a private laboratory and a couple of thousands more when the patient is admitted to a private hospital.Under the national guidelines, there are three testing categories depending on the symptoms, severity and vulnerability of high-risk patients, such as pregnant women, senior citizens, children, people with hypertension, diabetes, etc.Physicians also blamed patients who insist on getting tested.A doctor from Saifee Hospital cited the example of a family where three members had flu like symptoms. “They had already got tested at one of the private labs. They came to consult me only because one had tested positive,“ said infectious disease consultant Dr Vasant Nagvekar.The unusual rush of samples has also led to a delay in providing reports. Some private labs take up to two days to give the report. “At the Kasturba hospital, we are giving the molecular test reports within 4-5 hours,“ said Dr Jayanti Shastri, head of the Kasturba laboratory.But patients have complained that availing the testing facility at Kasturba Hospital is not easy. Advocate Adil Khatri said his family friend's child, who was recommended the test, was denied the facility till she got admitted to the hospital.