Exclusive: No, CT-scans haven’t replaced RT-PCR for detecting Covid! Here’s what top experts say

The RT-PCR tests continue to be the gold standard but there may be instances where there may be a false negative but the clinician is clearly able to identify the symptoms and signs. (File Photo)

Rahul Sharma (name changed on request) is a software engineer in his 30s. Last month in April, Sharma started experiencing flu-like symptoms. Without wasting any time, the family decided to go for rapid antigen tests, which gave negative results. The symptoms persisted and Sharma was advised to take the RT-PCR test. Considered as the gold standard test for detecting coronavirus, RT-PCR test also showed that Sharma didn’t have any kind of viral infection. The situation deteriorated and the family consulted another doctor, who in turn told Sharmas to get a chest X-ray and HRCT. After week-long dilemma, the family finally got a confirmation about the Covid-19 infection. Recuperating at home after a brief hospitalisation, Sharma is now convinced that it was CT-SCAN that saved his life. “RT-PCR can’t be trusted anymore,” Sharma says.

Why this push for CT-Scans?

Rahul Sharma is not alone. More and more people are turning to HRCT or High-Resolution CT scans to understand the extent of the infection. A young PR professional in her 20s decided to go for a CT scan as she felt that it gave her ample time to understand the degree of infection before the situation worsens. The younger population in their 20s and 30s are opting for HRCT even if they have a mild infection. Most feel that the CT scan helps to know the condition of the lungs before one starts gasping for air.

Take for the example case of Jyoti Kumar. Kumar didn’t even wait for RT-PCR when her father showed Covid-like symptoms. She says that she went for CT-Scan straight away on third of noticing symptoms. Many say that they are being advised to go for CT-Scan after usual medication doesn’t help in improving the symptoms. However, when contacted by FE Online, physicians refused to comment. But the trend on social media Covid SOS also shows more and more people are mentioning their ‘CT score’ while asking for help.

Despite caution, debate continues

The CT scan is not only a financially very expensive test but it also drains an individual physically. The trend is becoming a headache for health experts. On Monday during the routine pandemic update, AIIMS Chief Dr Randeep Guleria specifically addressed this issue saying that those with mild symptoms must refrain from CT-scan. He said that every single high-res scan is equivalent to 300 X-rays. He also added that this exposes the patient to high-level of radiations, which can also increase the risk of cancer! Despite this dire warning by Dr Guelria, the CT scan vs RT-PCR debate continues.

Patient symptoms, not scans matter

In order to get an expert view on the options before the patients and the right way forward on treatment, Financial Express Online reached out to Dr Soumya Swaminathan, Chief scientist at the World Health Organisation (WHO) and says, “It is not so much about the type of test but more about treating the patient. In times such as this if there is shortage of tests then physicians would be well advised to use a syndromic approach to treating the patient.” She also made it clear that one should understand that in medical world so far there is particularly no hard and fast rule that CT scans should definitely need to be done. “In fact, an ordinary chest x-ray could provide enough information.”

What if patients are told that the RT-PCR tests are not able to identify the variants, the veteran scientist, who was the former director general of the Indian Council of Medical Research (ICMR) says, “it is wrong to say that RT-PCR tests are not able to identify the variants. The RT-PCR tests continue to be the gold standard but there may be instances where there may be a false negative but the clinician is clearly able to identify the symptoms and signs. In such cases, physicians can arrive at the diagnosis on clinical and radiological grounds with the help of just an X-ray or perhaps in some cases a CT-scan.”

She reminds us “it is also important to remember that if the clinical condition of a patient is such that he or she needs immediate treatment then the doctor is not going to wait for the test reports. Rapid tests are also used in situations where the viral transmission is high. Even though the sensitivity of rapid tests is lower than RT-PCR, they can prove very handy in some situations. For example, when family members need to be tested if somebody in the family is sick then definitely rapid tests can be used to confirm and get the result in say about 30 minutes.”

In severe cases when the oxygen levels are dropping then the priority would be the management of the patient and making oxygen available and at that stage, the CT scan values do not add much. The clinical condition and oxygen saturation levels of the patient, she says, matter more than just the CT scan scores. The key message is that with the rising caseload of covid, it is the symptoms and signs that should guide management and covid would be the initial diagnosis till proven otherwise by say a rapid test or an x-ray.

Data can guide future actions

The focus now, says Dr Swaminathan, should be to contain the spread of the virus to locations beyond the hotspots and for that ideally, it is important to look at the district-wise granular data. This alone can guide us to the path of the virus and take action to stay ahead of it. Data on district-wise tests done and test positivity will be crucial. “Along with the data on test positivity, knowledge about the availability of hospital beds is critical and if these rates are rising and beyond manageable levels then,” the doctor says, “stricter public health measures may be required.”