Since July 1, Bengaluru has registered 15,147 cases, including 1,315 reported on Monday. (Express photo)

Despite scepticism among some experts over use of X-rays as a tool to diagnose lung infections caused by Covid-19, the Karnataka government has decided to go for large-scale purchase of digital X-ray machines as a tool to diagnose lung infections and prevent coronavirus-linked deaths.

On Monday, state Medical Education Minister Dr K Sudhakar said , “Digital X-rays can carry out 1,000 X-rays per day. With digital X-ray we can assess if the lungs are infected. It is a simple tool to detect an infection in early stage. If there is evidence of lung infection, then the person can be admitted in hospital immediately and lives can be saved.”

“We have decided to buy digital X-rays for every medical college, and the Health Department must buy them wherever they have hospitals — the Chief Minister has ordered,” the minister, overall in-charge of measures to control spread of Covid-19 in Karnataka, said.

X-rays have been used widely to assess lung conditions of front-line workers in the battle against the virus, such as policemen.

“We have used X-ray as a first test for policemen and have found it to be a useful tool to identify people who may be infected by the coronavirus,” state Revenue Minister R Ashoka, who is also involved in Covid-19 control measures in Bengaluru, said recently.

At Rajiv Gandhi Institute of Chest Diseases in Bengaluru, a government hospital that has a dedicated Covid-19 treatment facility, X-rays have been regularly used to assess whether patients showing up with SARI or Influenza-Like Illness need hospitalisation. The institute’s director, Dr C Nagaraja, said that in coronavirus, X-rays are “only a supportive tool for diagnosis; lab tests are the primary tool”. But since labs these days are taking four to five days to provide results, “it is OK to take chest X-rays since lesions show up in X-rays in about five to six days. It is being used to decide on admissions since results are delayed,” he said.

But experts like epidemiologist Dr Giridhar R Babu, who is a part of a technical committee constituted by Karnataka government for advice on tackling the pandemic, have cited findings from the British Society of Thoracic Imaging to question the wisdom of using X-rays as a diagnostic tool for Covid-19. “How much of use is X ray to screen Covid 19 while cases are surging? The BSTI radiology decision tool for suspected COVID-19 indicates it is for persons with lower respiratory tract involvement. Why is the Government proposing this for screening in Karnataka?” Dr Babu, an epidemiologist from the Public Health Foundation of India, recently posted on social media.

The BSTI radiology decision tool says that chest X-rays are to be done after clinical assessment and lab tests have confirmed Covid-19 infection and mostly in cases where patients are very ill.

Pulmonologist Dr K S Sathish, who is also part of the government expert panel, said, “Use of regular X-rays for assessing lung infection is not possible due to factors like contamination of X-ray facility in a lab but a mobile digital X-ray can be useful.”

X-rays are already being used across hospitals as a supportive diagnostic tool to assess if patients showing up with breathing problems are possibly infected by Covid-19 but not as a primary tool, as there are doubts over whether lesions that show up in X-rays are indicative of Covid-19 infections.

With results for RT-PCR tests in overworked laboratories in cities such as Bengaluru getting increasingly delayed by up to a week given the huge sample load, medical practitioners in Bengaluru have been frequently turning to X-rays to decide on hospitalisation of patients.

Earlier, on the advice of experts the Karnataka government had ordered widespread use of pulse oximeters to assess oxygen saturation levels in people as a first level of clinical assessment for Covid-19 before an RT-PCR lab test. Some experts are of the view that pulse oximeters are sufficient to assess lung functioning in suspected Covid-19 cases.

Diagnostic tools such as X-rays and CT scans are, however, reported to be in use in places like Mumbai where there has been a high incidence of cases and a lag in RT-PCR lab tests.

In Bengaluru, laboratories have seen a huge pile-up of samples in recent weeks after a few members of the staff of three key labs tested positive. As a result, nearly 11,000 samples were pending for testing at the beginning of July. Against its daily testing target of 4,370 samples, the Bengaluru urban region achieved only 59 per cent of the target on July 12.

Since July 1, Bengaluru has registered 15,147 cases, including 1,315 reported on Monday.