Doctors are also able to identify a possible novel coronavirus infection from a chest X-ray and other medical investigations
Nafia Jesmin (not her real name) began to exhibit symptoms similar to those of Covid-19, fever and a sore throat, yesterday. Herself a doctor, having completed her last shift at a private hospital five days ago, she considered taking a polymerase chain reaction (PCR) test to determine whether she had contracted the virus.
She called the dedicated hotline numbers and contacted public and private facilities, but to her dismay, she learned that none of them could collect her sample from home until four to five days later. Instead, she would have to stand in long queues in front of testing facilities. The thought of catching the virus while waiting in line, if she had not already been infected, deterred her.
The doctor considered waiting another day to see if the symptoms intensified and required her to be hospitalised. Many of the hospitals – both public and private – that have been designated by the government for novel coronavirus treatment, ask patients to get PCR test results before admission.
The limited number of labs, now 43, compared to the crowds of people who show up with symptoms for tests, lengthen the waiting time for the results by two to five days.
The time could be crucial for a patient. A fatal consequence might be avoidable if a patient receives immediate treatment – any hospital's failure to provide care in an emergency is unacceptable.
Treatment should not rely on test results
There is no single proven treatment for Covid-19. What doctors suggest is symptomatic treatment evolving on the basis of their hands-on experience with patients.
People with mild symptoms can stay home, isolated from other members, but those with a history of comorbidities and with moderate to severe signs, must be admitted to hospital.
"The Directorate General of Health Services has issued treatment guidelines and nowhere it said that PCR test result is required before hospital admission," said Robed Amin of the medicine department at Dhaka Medical College Hospital.
"We begin treatment on grounds of clinical judgment," he said.
From a chest X-ray and other medical investigations, doctors can identify a possible infection of the novel coronavirus.
The purpose of test
Additionally, there is a risk of 30 percent of PCR test results showing false negatives but that should not deprive a patient of treatment, Amin added.
So, why is the test required?
The World Health Organisation recommends testing to identify cases of infection, isolate them and trace their contacts – and that is the most effective way found until now to curb the virus' transmission.
The PCR test, that detects the genetic material from the virus, can help diagnose an active Covid-19 infection. It is "incredibly accurate" with the setback that the test and analysing the results take time, according to the US Food and Drug Administration (FDA).
Against the backdrop of researchers and scientists scrambling to find a quicker and cheaper alternative to PCR testing, the FDA has authorised 12 antibody tests and one antigen test under a special arrangement called Emergency Use Authorisation (EUA) to speed up the review process and give permission.
The authorisations came along with notes of caution.
The antigen test detects fragments of protein found on or within the virus. One of the main advantages of it is the speed of the test, which can provide results in minutes, the FDA said in its latest EUA announcement on May 9 for an antigen test.
However, an antigen test may not detect all active infections because it is not as sensitive as the molecular PCR test.
"Positive results from antigen tests are highly accurate, but there is a higher chance of false negatives, so negative results do not rule out infection. With this in mind, negative results from an antigen test may need to be confirmed with a PCR test prior to making treatment decisions or to prevent the possible spread of the virus," read the announcement.
Since the antigen test is cheaper, it can help scale up the testing process to find out the infection rate closer to real time.
The antibody test that finds out if the body's immune system is responding to the pathogen is not appropriate to diagnose an active Covid-19 infection, the FDA warns. At the initial stage of the infection, the test may fail to identify antibodies.
However, such a test could play a role in the fight against Covid-19 by helping healthcare professionals identify individuals who have developed an adaptive immune response to Covid-19.
Dr Jahidur Rahman of the virology department of Shaheed Suhrawardy Medical College and Hospital said the PCR test is the most efficient one and as the country has entered the phase of community transmission, it should intensify its testing capacity to contain it.
However, he said effective antigen and antibody tests would result in an enhanced capacity to draw the actual rate of infections.
Virologist Prof Saif Ullah Munshi of Bangabandhu Sheikh Mujib Medical University said the two inexpensive tests can reduce pressure on the PCR test.
"Those with mild symptoms are advised to stay home. The health condition of some of them becomes critical seven to eight days after contracting the infection," he said.
"They might need immediate hospitalisation and a quicker test may facilitate this," Munshi added.