TAIPEI, Taiwan >> Lu Muying died on April 1 in a government quarantine facility in Shanghai, with her family on the phone as doctors tried to resuscitate her. She had tested positive for COVID-19 in late March and was moved there in line with government policy that all coronavirus cases be centrally isolated.

But the 99-year-old, who was just two weeks shy of her 100th birthday, was not counted as a COVID-19 death in Shanghai’s official tally. In fact, the city of more than 25 million has only reported 25 coronavirus deaths despite an outbreak that has spanned nearly two months and infected hundreds of thousands of people in the world’s third-largest city.

Lu’s death underscores how the true extent of the virus toll in Shanghai has been obscured by Chinese authorities. Doctors told Lu’s relatives she died because COVID-19 exacerbated her underlying heart disease and high blood pressure, yet she still was not counted.

Interviews with family members of patients who have tested positive, a publicly released phone call with a government health official and an internet archive compiled by families of the dead all raise issues with how the city is counting its cases and deaths, almost certainly resulting in a marked undercount.

The result is a blurred portrait of an outbreak that has sweeping ramifications for both the people of Shanghai and the rest of the world, given the city’s place as an economic, manufacturing and shipping hub.

An Associated Press examination of the death toll sheds light on how the numbers have been clouded by the way Chinese health authorities tally COVID-19 statistics, applying a much narrower, less transparent, and at times inconsistent standard than the rest of the world.

In most countries, including the United States, guidelines stipulate that any death where COVID-19 is a factor or contributor is counted as a COVID-related death.

But in China, health authorities count only those who died directly from COVID-19, excluding those, like Lu, whose underlying conditions were worsened by the virus, said Zhang Zuo-Feng, an epidemiologist at the University of California, Los Angeles.

“If the deaths could be ascribed to underlying disease, they will always report it as such and will not count it as a COVID-related death, that’s their pattern for many years,” said Jin Dong-yan, a virologist at the University of Hong Kong’s medical school.

That narrower criteria means China’s COVID-19 death toll will always be significantly lower than those of many other nations.

Both Jin and Zhang said this has been China’s practice since the beginning of the pandemic and is not proof of a deliberate attempt to underreport the death count.

However, Shanghai authorities have quietly changed other standards behind the scenes, in ways that have violated China’s own regulations and muddied the virus’ true toll.

During this outbreak, Shanghai health authorities have only considered virus cases where lung scans show a patient with evidence of pneumonia as “symptomatic,” three people, including a Chinese public health official, told the AP. All other patients are considered “asymptomatic” even if they test positive and have other typical COVID-19 symptoms like sneezing, coughing or headaches.

This way of classifying asymptomatic cases conflicts with China’s past national guidelines. It’s also a sharp change from January, when Wu Fan, a member of Shanghai’s epidemic prevention expert group, said that those with even the slightest symptoms, like fatigue or a sore throat, would be “strictly” classified as a symptomatic case.

Further adding to the confusion, the city has overlapping systems to track whether someone has the virus. City residents primarily rely on what’s called their Health Cloud, a mobile application that allows them to see their COVID-19 test results. However, the Shanghai health authorities have a separate system to track COVID-19 test results, and they have the sole authority to confirm cases. At times, the data between the systems conflict.

In practice, these shifting and inconsistent processes give China’s Centers for Disease Control and Prevention “wiggle room” to determine COVID-related deaths, said the Chinese health official, allowing them to rule out the coronavirus as being the cause of death for people who didn’t have lung scans or positive test results logged on their apps. The official spoke on condition of anonymity to discuss the sensitive topic.

In response to questions about Shanghai’s COVID-19 figures, China’s top medical authority, the National Health Commission, said in a fax that there is “no basis to suspect the accuracy of China’s epidemic data and statistics.” Shanghai’s city government did not respond to a faxed request for comment.

Statements from the authorities are little comfort to the relatives of the dead. Chinese internet users, doubting the official figures, have built a virtual archive of the deaths that have occurred since Shanghai’s lockdown based on firsthand information posted online. They have recorded 170 deaths so far.

Chinese media reports on the unrecorded COVID-19 deaths have been swiftly censored, and many criticisms of Shanghai’s stringent measures expunged online. Instead, state media has continued to uphold China’s zero-COVID approach as proof of the success of its political system, especially as the world’s official death toll climbs past 6.2 million.

Earlier this month, doubts over the data burst into public view when a Shanghai resident uploaded a recording of a phone conversation he had with a CDC officer in which he questioned why city health authorities told his father he had tested positive for COVID-19 when data on his father’s mobile application showed up as negative.

“Didn’t I tell you to not look at the Health Cloud?” said the official, Zhu Weiping, referring to the app. “The positive cases are only from us notifying people.”

Others skeptical of the data include relatives of Zong Shan, an 86-year-old former Russian translator who died March 29. Despite testing positive and being moved to a government quarantine facility, online test results showed Zong supposedly was negative for COVID-19 on the day of her death.

“My relative, like most of the other people in Shanghai who were notified as positive, all reported negative results” on the Health Cloud app, one of Zong’s relatives said, declining to be named for fear of retribution.

Zong was taken to a government quarantine facility from the Donghai Elderly Care Hospital on March 29, and died there that night. The family was told by hospital staff she was being transferred after she tested positive for COVID-19. But they didn’t think the virus was the biggest threat to her health — rather, it was the dearth of nursing care at the quarantine facility. Zong needed to be fed liquids and couldn’t eat without assistance.

She had been in stable condition before the transfer, said a relative. When the family asked for the cause of death, doctors didn’t give a clear answer.

“They gave me very vague answers. One minute they said it was stroke, then they said this was also just a hypothesis,” said the relative. “But on one point, they were very clear, they said it had nothing to do with COVID. Her lungs were clear.”

Lu, who was also transferred from the Donghai hospital, would have celebrated her 100th birthday April 16; her relatives had ordered a cake and gotten permission to host a small celebration Thursday. But when she tested positive, the family made mental preparations for her death, acknowledging she had lived a long life.

But the strange thing, a relative said, was the night before she died, the doctor had specifically called the family to let them know Lu was now testing negative for COVID-19. Ultimately, the doctor said she died because the virus had worsened her underlying illnesses, said the relative, speaking on condition of anonymity to discuss the issue.

Further, the family knew of another patient from the same hospital, a neighbor, who died the day after being transferred to a quarantine facility on March 25 and also had not been counted.

Jin, the Hong Kong virologist, noted the potential political benefits of Shanghai’s low official COVID-19 death toll.

“They might claim this is their achievement, and this is is their victory,” Jin said.