Last week, a 16-month-old boy in Florida tested positive for the new coronavirus, a lab report shows. A few days later, he tested negative at a second lab. The chief medical officer at the practice where the tests were ordered is betting that the positive result is the right one. “A false negative is problematic because it tells the patient they don’t have the virus,” said the doctor, Craig Deligdish, an oncologist at Omni Healthcare, a Melbourne, Fla., medical group. Meanwhile, that patient can unwittingly spread it, he said. Health experts say they now believe nearly one in three patients who are infected are nevertheless getting a negative test result. They caution that only limited data is available, and their estimates are based on their own experience in the absence of hard science. That picture is troubling, many doctors say, as it casts doubt on the reliability of a wave of new tests developed by manufacturers, lab companies and the U.S. Centers for Disease Control and Prevention. Most of these are operating with minimal regulatory oversight and little time to do robust studies amid a desperate call for wider testing. “The whole testing field is in flux,” said Bill Miller, a physician and epidemiologist at the Ohio State University. “The thing that is different this time is most of these tests are going through a really rapid validation process. As a result we can’t be completely confident in how they will perform.” The unknown rates of false-negative results could leave patients with unjustified confidence that they can return to business as usual and could show that the nation’s view into the spread of the disease has a blind spot, Dr. Miller said. All lab tests have some margin of error, measured in terms of sensitivity— the percent of positive cases a test accurately detects—and specificity, the percent of negative cases it accurately detects. The sensitivity of the currently available coronavirus tests seems to be lower than other similar tests, said Mike Lozano, a Tampa, Fla.,-based executive at Envision Healthcare Corp., a medical group that contracts to provide care at hospitals. Dr. Lozano said he estimates that the sensitivity of the tests is in the neighborhood of 70%, meaning nearly one in three positive patients walks away with a reassuring negative result. Chris Smalley, a primary-care doctor at Louisville, Ky.,-based Norton Healthcare, said the 70% estimate was gaining traction with doctors finding out how well the tests work in the real world, absent better data. He said several of his patients with negative tests went on to develop highly suspicious coronavirus symptoms and require long hospital stays. Dr. Smalley said a negative result is more likely to be accurate in places like Louisville where the prevalence is low, but could be virtually useless in New York, where it is high. A February study of about 1,000 patients in Wuhan, China, who were hospitalized with suspected coronavirus there, where the pandemic began, found that about 60% tested positive using lab tests similar to those available in the U.S. But, almost 90% showed tell-tale signs of the virus in CT scans of their chests, the article, published in the journal Radiology, found, suggesting many patients in the group were testing negative despite active coronavirus infections. The technology that underpins the new coronavirus tests so far available, a genetic method called polymerase chain reaction, typically detects over 90% of positive cases accurately, said Tom Taylor, a professor and former CDC statistician. In less dire circumstances, he said, the CDC would typically do a study to verify the accuracy of such tests, which might take a year. The U.S. Food and Drug Administration initially required testing companies to submit applications for new tests, a move the agency said was required by law. Critics said that deterred private companies from moving quickly to develop badly needed tests. As demand surged in late February, the agency relaxed the requirements, saying labs could start testing without approval and submit their internal studies later. Published details of those studies are often limited. In a statement Monday, the FDA said it is balancing the need for more testing with its prerogative to ensure tests are accurate. Right now, the FDA’s priority remains getting more tests into the field, an agency spokeswoman said. A Dallas-area emergency-room doctor, Peter Brokish, said several lab results he had sent to Laboratory Corp. of America Holdings came back negative only to have the patients return to the emergency department where he works with worsened symptoms, including fevers and coughs. After being admitted to a hospital, they tested positive. “You kind of figure, yeah, that’s a false negative,” Dr. Brokish said. Linda Girgis, a New Jersey primary-care doctor, saw the same pattern with a test run for a health-care worker by Quest Diagnostics Inc., a finding that made her fear that frontline workers might report for duty thinking they weren’t contagious. “Our materials for providers, including our test reports, make clear that while these tests are designed to minimize false negatives and false positives, such results can occur,” said Wendy Bost, a Quest spokeswoman. A Labcorp spokesman said that while a positive result is a definitive sign of coronavirus infection, “a negative result does not definitively rule out infection.” He said test accuracy can be affected by how a specimen is collected, and how long an individual has been infected before testing. In New York City, “a negative is not clearing anybody who is symptomatic,” said Dara Kass, an emergency-room doctor at NewYork-Presbyterian, a hospital system. Dr. Kass, who is working from home after she tested positive for coronavirus in mid-March, said all patients with symptoms are being treated as coronavirus-positive, because the disease is so widespread in the city. 。。。。。
下面评论之一，都呼吸困难去医院了，测试回来阴性，给送回家了。 18 hours ago I was hospitalized for shortness of breath and a racing heart after being sick for a week. Everyone in the ER, including the attending, was certain I had it. Two days later, the test was negative and as I did not have a fever and or pneumonia, was sent home. I was told to get a sleep test to examine my symptoms. My husband and I decided on our own to treat it as if I have it, a few days before all of these stories came out. We have been keeping as separate as possible but now I am afraid he has it. The entire thing is so frightening - after seeing how busy the hospital was, I pray neither of us will need to go back. It seems there is no safe place right now.
你这个数学不行哈。 “Dr. Lozano said he estimates that the sensitivity of the tests is in the neighborhood of 70%, meaning nearly one in three positive patients walks away with a reassuring negative result.” 是实际13%的阳性。
https://www.wsj.com/articles/questions-about-accuracy-of-coronavirus-tests-sow-worry-11585836001
真是无语，这是要把大陆踩过的雷，一个不落，统统加倍再踩一遍啊
貌似昨天briefing上，dr. Birx驳斥过这个fake news 了。
如果不能保证排除假阴性，就不应该把医院船用来收治非新冠病人，美国对中国的经验教训不屑一顾，要再付出多少人命？
She is a moron. 就会拍马屁。
怎么能质疑伟大的美国呢？ 楼主肯定是是小粉红。只有中国才会制造劣质试剂，嗯，就酱紫
不知道放走多少假阴性了。
你还信birx的话？她就是个政客，要听dr.fauci讲话。
Last week, a 16-month-old boy in Florida tested positive for the new coronavirus, a lab report shows. A few days later, he tested negative at a second lab. The chief medical officer at the practice where the tests were ordered is betting that the positive result is the right one. “A false negative is problematic because it tells the patient they don’t have the virus,” said the doctor, Craig Deligdish, an oncologist at Omni Healthcare, a Melbourne, Fla., medical group. Meanwhile, that patient can unwittingly spread it, he said. Health experts say they now believe nearly one in three patients who are infected are nevertheless getting a negative test result. They caution that only limited data is available, and their estimates are based on their own experience in the absence of hard science.
That picture is troubling, many doctors say, as it casts doubt on the reliability of a wave of new tests developed by manufacturers, lab companies and the U.S. Centers for Disease Control and Prevention. Most of these are operating with minimal regulatory oversight and little time to do robust studies amid a desperate call for wider testing. “The whole testing field is in flux,” said Bill Miller, a physician and epidemiologist at the Ohio State University. “The thing that is different this time is most of these tests are going through a really rapid validation process. As a result we can’t be completely confident in how they will perform.” The unknown rates of false-negative results could leave patients with unjustified confidence that they can return to business as usual and could show that the nation’s view into the spread of the disease has a blind spot, Dr. Miller said. All lab tests have some margin of error, measured in terms of sensitivity— the percent of positive cases a test accurately detects—and specificity, the percent of negative cases it accurately detects. The sensitivity of the currently available coronavirus tests seems to be lower than other similar tests, said Mike Lozano, a Tampa, Fla.,-based executive at Envision Healthcare Corp., a medical group that contracts to provide care at hospitals. Dr. Lozano said he estimates that the sensitivity of the tests is in the neighborhood of 70%, meaning nearly one in three positive patients walks away with a reassuring negative result. Chris Smalley, a primary-care doctor at Louisville, Ky.,-based Norton Healthcare, said the 70% estimate was gaining traction with doctors finding out how well the tests work in the real world, absent better data. He said several of his patients with negative tests went on to develop highly suspicious coronavirus symptoms and require long hospital stays. Dr. Smalley said a negative result is more likely to be accurate in places like Louisville where the prevalence is low, but could be virtually useless in New York, where it is high. A February study of about 1,000 patients in Wuhan, China, who were hospitalized with suspected coronavirus there, where the pandemic began, found that about 60% tested positive using lab tests similar to those available in the U.S. But, almost 90% showed tell-tale signs of the virus in CT scans of their chests, the article, published in the journal Radiology, found, suggesting many patients in the group were testing negative despite active coronavirus infections. The technology that underpins the new coronavirus tests so far available, a genetic method called polymerase chain reaction, typically detects over 90% of positive cases accurately, said Tom Taylor, a professor and former CDC statistician. In less dire circumstances, he said, the CDC would typically do a study to verify the accuracy of such tests, which might take a year. The U.S. Food and Drug Administration initially required testing companies to submit applications for new tests, a move the agency said was required by law. Critics said that deterred private companies from moving quickly to develop badly needed tests. As demand surged in late February, the agency relaxed the requirements, saying labs could start testing without approval and submit their internal studies later. Published details of those studies are often limited. In a statement Monday, the FDA said it is balancing the need for more testing with its prerogative to ensure tests are accurate. Right now, the FDA’s priority remains getting more tests into the field, an agency spokeswoman said. A Dallas-area emergency-room doctor, Peter Brokish, said several lab results he had sent to Laboratory Corp. of America Holdings came back negative only to have the patients return to the emergency department where he works with worsened symptoms, including fevers and coughs. After being admitted to a hospital, they tested positive. “You kind of figure, yeah, that’s a false negative,” Dr. Brokish said. Linda Girgis, a New Jersey primary-care doctor, saw the same pattern with a test run for a health-care worker by Quest Diagnostics Inc., a finding that made her fear that frontline workers might report for duty thinking they weren’t contagious. “Our materials for providers, including our test reports, make clear that while these tests are designed to minimize false negatives and false positives, such results can occur,” said Wendy Bost, a Quest spokeswoman. A Labcorp spokesman said that while a positive result is a definitive sign of coronavirus infection, “a negative result does not definitively rule out infection.” He said test accuracy can be affected by how a specimen is collected, and how long an individual has been infected before testing.
In New York City, “a negative is not clearing anybody who is symptomatic,” said Dara Kass, an emergency-room doctor at NewYork-Presbyterian, a hospital system. Dr. Kass, who is working from home after she tested positive for coronavirus in mid-March, said all patients with symptoms are being treated as coronavirus-positive, because the disease is so widespread in the city. 。。。。。
7，谁都不能保证。哪有这么完美的测试？韩国那种大规模的测试，还有假阴性有监，假阳性游荡.....
18 hours ago
I was hospitalized for shortness of breath and a racing heart after being sick for a week. Everyone in the ER, including the attending, was certain I had it. Two days later, the test was negative and as I did not have a fever and or pneumonia, was sent home. I was told to get a sleep test to examine my symptoms. My husband and I decided on our own to treat it as if I have it, a few days before all of these stories came out. We have been keeping as separate as possible but now I am afraid he has it. The entire thing is so frightening - after seeing how busy the hospital was, I pray neither of us will need to go back. It seems there is no safe place right now.
反正中国做什么，都是技术太差了。
越来越反感birx
X-Ray是一个方向的投影
CT是切片照X-ray， 可以用软件形成3D结构，可以看到不同的东西
不是的，这个病XRay没用，经常xray看上去没问题，ct一看已经感染很多了
下呼吸道这个有文章可以分享一下么？昨天那篇nature文章好像说这个病毒在没有症状或者上呼吸道到感染初期前五天就达到peak time ，然后下降，没仔细看，也许看错了
你觉得她得话，现在可信度有多高？
你根本不懂，核酸检测都是一样原PCR理，灵敏度和特异性都是非常高，全世界都一样，没多大差异。除了无能CDC能mess up。
取样问题不是换台仪器就能解决的。