The effectiveness of the coronavirus test kit is under questioning after a confirmed patient failed three times to test positive for the virus, Beijing News reported.

Before the patient who flew from Wuhan to Beijing was diagnosed with the 2019-nCoV at the China-Japan Friendship Hospital on Friday, only his oropharyngeal swabs had tested positive for the 2009 H1N1 virus.

He was at first treated as a severe 2009 H1N1 virus patient when admitted to the hospital on January 30. Only after the bronchoalveolar lavage, a lower respiratory tract test in which a bronchoscope is passed through the mouth or nose into the lungs to collect the samples did the doctors spot the novel coronavirus.

A respiratory physician in Beijing told Beijing News a routine checkup to a suspect case requires two oropharyngeal swabs tests. As long as there is one positive result, then the case can be confirmed by doctors. But only when both results are negative, the possibility of having the virus can be ruled out.

The patient's oropharyngeal swabs tests against 2019-nCoV returned negative three times.

"Lesions occur in the lungs, that is, the lower respiratory tract, sometimes just testing the oropharyngeal swabs in the upper respiratory tract cannot help find the pathogen," Ding Xinmin, chief physician of the respiratory department at Beijing Shijitan Hospital explained.

"That's why the patient was confirmed after the bronchoalveolar lavage test," he added.

On Sunday's press conference, Xu Shunqing, deputy dean of school of public health at Huazhong University of Science and Technology also explained the special case found in the Beijing hospital, saying that a chest CT scan may help reduce the missed diagnosis.

A chest CT scan will take detailed pictures of lungs where the lesions occur. 

"Previously, test kits were the only tool to diagnose the coronavirus, now, we will take patients' CT results and their clinical symptoms into consideration," Xu said. 

The new fifth edition of China's Diagnosis and Treatment for Novel Coronavirus has added CT results into the clinical evidence to help doctors diagnose cases.

Diagnostic test kit in China

The nucleic acid test kit is an essential diagnostic tool to combat against the novel coronavirus pneumonia. According to Xinhua, more than 43,000 samples had been tested in Wuhan, the epicenter of the pneumonia outbreak.

As the confirmed cases spiral, the demand for the test kit is also growing. China's National Medical Products Administration (NMPA)  has granted medical device registration certificates to seven companies who have been producing the diagnostic test kits.

On Sunday's press conference held by the National Health Commission, a CCTV reporter raised questions to NMPA's staff whose responsibility is to make sure the companies have the qualifications and can guarantee the effectiveness and safety of the test kits. 

Jiang Deyuan, medical device inspection department specialist at NMPA, said the products had been proven effective in the clinical trials, the reason they can have quick approval is that they are in the emergency approval list.

On January 22, the NMPA organized a group of China's Center for Disease Control the best clinic physicians to evaluate and review the effectiveness of the nucleic acid test kits for the new coronavirus, in a move to speed up the products' application process.

"Products quality and safety are well guaranteed. We set strict application standards for the test kits at both provincial and national level," Jiang stressed.