Nucleic acid dilemma: 3 institutions were filed in 10 days, and false negatives and false positives appeared frequently. Why did it become a high-risk industry?

In the past three days, Jinzhun Medicine and Zhongtong Lanbo have been in Beiji.

It is reported that the former's "illegal and criminal behavior" is "three-tube mixed-tube testing of multi-tube samples"; the latter is "part of the amplification file records do not match the laboratory's self-reported testing quantity, and multi-tube samples are mixed-tube testing in violation of regulatio.

A week ago, because "the original test data was significantly less than the number of samples tested", Beijing Pu Shi Medical Laboratory .

In addition, on May 21, Beijing Changping police reported an illegal act of forging and purchasing false nurse practitioner certificates to defraud the qualifications for nucleic acid sampling; on May 22, a nucleic acid testing site in Beijing was notified and fined for using expired sample preservation soluti.

There have been at least five cases related to nucleic acid testing violations in the current round of the Beijing epidemic that began on April 2

Nucleic acid testing chaos is not only happening in Beiji.

In January, during the epidemic in Yuzhou, Henan, Zhang Moudong, an employee of Zhengzhou Jinyu, was accused of "carrying out behaviors that caused the spread of novel coronavirus pneumonia or had a serious risk of spreadin.

In April, Hefei Hehe Medical Laboratory and Hefei Nuoweier Medical Laboratory were accused of having super-capacity to undertake the testing business, issuing test reports seriously over the promised time, and issuing "false positive" reports several tim.

In May, the positive results issued by Shanghai Zhongke Runda Precision Medical Testing .

8:00 Jianwen learned that in a city where the epidemic broke out, the relevant departments will frequently conduct on-site inspections of the testing institutions, "always find some small problems, and then supervise the improveme.

Accuracy sacrificed by time

No diagnostic technology is 100% accura.

Guo Yanhong, Inspector of the Medical Administration and Hospital Administration, introduced at the press conference of the Joint Prevention and Control Mechanism of the State Council on the 23rd, "Although the specificity of our nucleic acid test is 100%, in actual work, the laboratory may cause problems due to the test process and operati.

Theoretically 100%, in practice, there are ubiquitous pollution challenges in the whole process from collection to inspecti.

An inspector who just participated in a large screening in the north encountered a case of sampling contamination: the gymnasium of a university was used to vaccinate students on the first day, and nucleic acid samples were taken for the students on the second day, and the nucleic acid test results were all positi.

The same sampling pollution is not an isolated ca.

In the testing process, the process control of each laboratory is particularly critic.

Regardless of true or false positives, in accordance with the relevant regulations such as the "New Coronavirus Nucleic Acid Detection Workbook for Medical Institutions" and other relevant regulations, the laboratory should "use one or two other nucleic acid detection reagents that are more sensitive and amplify different regions for each abnormal resu.

According to the norm, under multiple guarantees, "after 2-3 rounds of review, false positives can basically be ruled ou.

In the aforementioned pollution incident, it took the aforementioned inspector a week to review and analyze the cause of the polluti.

For laboratories with relatively mature quality control, in large-scale screening, the most critical trouble comes from ti.

In local screening, it is normal to require 6 hours for results, and a person in charge of a third-party agency pointed out: "This time is simply too late to revi.

"

Eight points of Jianwen has learned from many sources that in order to speed up the screening, some areas in Shanghai cancelled the review mechanism during the peak period of the epidem.

According to the test, the time limit given in the Shanghai epidemic is "6 hours of chasing the sun", and "the time is quite urgen.

During the period of time when the sun chasing is not timely, some incidents of false positives being transferred are prone to occ.

It is also difficult for laboratories to maintain the intensity of quality control during mass screeni.

.

Meng Lingzhuo of Sidi Diagnostics revealed in a recent sharing meeting that the quality control theory is very classic and clear, but it is difficult to impleme.

During the large screening, the quality of consumables such as sampling tubes, the matching of instruments and reagents, and the calibration of instruments cannot be Control, "It is difficult to keep the environment clean in a 24-hour laborato.


Many inspectors fight continuously and can only rest in the laboratory at nig.

This series of problems is due to the huge scale of inspections, so it was not a probl.

The problem has also been highlight.

"

In order to further shorten the time for results, more and more laboratories are choosing rapid test reagen.

A practitioner in a related industry told Badianjianwen, "Rapid test reagents can play a greater role in emergencies, fever clinics and other scenarios that require higher timeliness, saving 40-60 minutes compared to conventional ordinary reagents, but the sensitivity If the ratio is lower, it may cause missed detecti.

”

An industry expert clearly told Badianjianwen that in the gray area of ​​35≤Ct value≤40, compared with standard reagents, the missed detection rate of some rapid test reagents can reach 5

Other "more, faster, better and more economical operations" include increasing the amount of enzyme used during amplification, changing the number of cycles, or mixing two tubes into one tube or multiple tubes in one tube for detecti.

The recently reported Jin Zhun and Zhongtong Lanbo Medical Laboratory have multiple-tube mixed inspectio.

An industry insider analyzed to Badian Jianwen that the reason why Beijing Pu Shi's "original test data is significantly less than the number of samples tested" is also likely to be multi-tube mixed-in-one inspection for the sake of speed or cost reducti.

In addition to the problems caused by rapid testing and mixed testing, some experts also reminded that the differences between reagents from different manufacturers also need to be paid attention .

If the Ct value of reagent A is less than or equal to 35, it is positive, and the Ct value of reagent B is less than or equal to 4 Taking the gray area subject's two reviews as an example, the result reported after A and B is actually "false negative", and B first The result reported by A is actually a "false positiv.

According to people familiar with the matter, in the nucleic acid false positive incident in Shanghai, the relevant departments have conducted certification assessments on the relevant laboratories involved, and the conclusion is that the laboratory's own inspection process and quality control are "no proble.

In order to solve all kinds of "false positive oolongs" caused by reagents and standards, a person in charge of a tripartite inspection agency suggested that between "negative" and "positive" of nucleic acid code inspection platforms in various places, add "abnormal" to mixed tub.

item, and it will show positive after single-tube revi.

Another expert suggested that the basic information of the reagents used should be published in the results to protect the subjects' right to kn.

Countless possibilities for false vaginas

Compared with false positives, "false negatives mean white testi.

" A practitioner in the testing industry told 8:00 Jianwen that residents took the risk of cluster infection to participate in sampling, but did not achieve the expected screening goa.

Even more troublesome, false positives can be resolved through quality control and review, but the only way to deal with false negatives is to increase the number of tes.

Therefore, when one round of testing cannot screen out all the positives, there is only one more rou.

The round of nucleic acid results in a rapid increase in the amount of testing, and the surging demand brings new challenges to production capacity and experimental specifications, which also lead to More false negatives and even false positiv.


The superposition of all these forms a vicious circle, with more and more nucleic acid tests, more and more false negatives and false positiv.

Compared with false positives, false negatives are more difficult to avoid because of the diverse causes and huge room for interpretati.

Jin Dongyan reminded that the scientific evaluation of the nucleic acid detection effect needs to consider the changes in the usage scenarios, "First, the viral load of Omicron is low; Some people have been vaccinated, and the immune situation has chang.

"

On May 16, "Nature" magazine published a preprinted paper from the famous Japanese virologist Kawaoka Yoshihi.

An important conclusion of this animal experiment is that PCR viral load detection showed that Omicron BA Both th.

1 and .

2 strains infected mice with lower viral loads in the lungs and nose than the original stra.

New strains are harder to dete.

In addition to the characteristics of the strain itself, changes in herd immunity brought about by vaccination can also increase the risk of missed detections and false negativ.

In addition to changes in the virus itself, the quality of manual sampling will directly affect the quality of testi.

However, compared to testing, sampling lacks effective quality control measures, and the methods and locations of sampling personnel cannot be trac.

An airport in the south, which has a high risk, uses monitoring to supervise the sampling behavior throughout the process, but in large-scale normalized screening, monitoring is not generalizable, which makes the sampling work "a conscience jo.

Jin Dongyan, a virologist at the University of Hong Kong, told Badianjianwen that the requirement for antigen sampling in Hong Kong in the later period was deep throat saliva, "requires residents to get up early in the morning and spit saliva 14 times into a tub.

While the mainland nucleic acid screening is mainly based on throat swabs, the actual sampling site is often the oral cavity, and the oral environment is unstab.

The subject's mouthwash, drinking water, and eating before sampling will theoretically affect the sampling quali.

If there is less detoxification and the sampling site is not good enough, it is difficult to capture a sufficient amount of virus, and mixed detection will further dilute the virus, making it more difficult to detect weak positiv.

Mixed testing has sacrificed the accuracy of nucleic acid to a certain exte.

Virology expert Chang Rongshan analyzed that, "One sampling cotton swab is soaked in 3 ml of sampling solution during apheresis, and ten swabs are used for mixed sampli.

Soaked in 12 ml of sampling solution, mixed and diluted samples, if the same sensitivity kit is used again, it is easy to cause false negatives, which is difficult to avo.

"

However, the Beijing Jinzhun Medical Laboratory adopted a combination of three tubes, five, and t.

"This method cannot guarantee the detection effect, and false negatives will definitely occur," Chang Rongshan told 8:00 Jianw.

From the point of view of the laws of detection science, the detection volume of tens of millions, whether it is collection or laboratory operation, system errors are unavoidab.

Chang Rongshan analyzed that if the positive rate is less than one ten thousandth, even if the mixed sampling Efficiency is the same as single test and apheresis, and false positives and false negatives are bound to occur, and the probability of false negatives is great.

This may be the key issue to be considered when adopting the "normalized nucleic acid testing" pl.

Virus characteristics, collection and inspection specifications, quality of reagents and consumables, personal detoxification characteristics and compliance of the subject are all closely related to the detection ra.

In addition to active fraud, the reason for the distortion of a test result is often an inevitable accide.

"Medical technology has high complexity, high risks and limitatio.

Variant viruses increase the difficulty of detecti.

Medical institutions cannot guarantee accurate detection of patients' conditio.

Misdiagnosis within a certain range is acceptab.

" The staff of the testing agency of the Ministry of Foreign Affairs told Eight Point Jianw.

Jin Dongyan reminded that it is necessary to pay attention to whether the comprehensive observation of a single nucleic acid test as the gold standard has reached the methodological lim.

Instead of paying too much attention to the horns of false negatives and weak positives, we should actually go back and discuss nucleic acid positivity and infectiousne.

Correlation, "a considerable number of people with positive nucleic acid are not infectiou.

The public does not understand all of these, and they have only one more intuitive feeling: nucleic acid tests are getting more and more dense, and there are more and more false negatives and false positiv.

Normalized nucleic acid dilemma

The four corners of normalized nucleic acid are money, people, time, and testing quality: companies must quickly complete testing with low cost, quality and quantity, local governments with different situations must prepare sufficient budgets, and there is also a shortage of personnel for normalized testi.

Fast delivery, and under these conditions, the timeliness must be improved as much as possible to meet the normalized life of residen.

The back of the four corners that are pulling each other is in an area where funds and personnel are not in pla.

How can normalized nucleic acid testing be completed in a high-quality and timely manner? It is not difficult for large-scale tripartite medical laboratories to transform into a normalized model in cities with abundant reserves and sufficient funds that have previously experienced large-scale screening, but how to solve the problem in areas that are not rich enough and lack normalized testing resources?

In the past, the sampling work was completed by local or regional or national medical support in the nucleic acid of all employees in various plac.

On the testing side, there has been a real dilemma of "140,000 testers doing nucleic acid for 4 billion people" in the past two yea.

However, after the normalization of nucleic acid, the medical and nursing force gradually withdraws, and some volunteers return to normal li.

These gaps must be filled with new personn.

Henan, a populous province that has announced normalized nucleic acid testing, plans to train 50,000 relevant personnel within the ye.

Eight points Jianwen learned through several education and training institutions that the requirements for recruiting and training inspection personnel vary from place to pla.

Some have "unlimited educational background", and some are "related to medicin.

There are online training and online examinations for 1,500 yu.

Those who get the certificate every week, there are also those who have trained for two months and offline field exams for "only 800 yua.

According to the "Notice of On-the-job Training for New Crown Nucleic Acid Testing Personnel" issued by a northern province that can be checked on the Internet, the trainees can get the nucleic acid testing laboratory after 3 days of training and one hour of online examinati.

The PCR work permit required by the operat.

A trainer told Eight Points Jianwen that although the job requirements in some areas are PCR job certificates, "Biosafety Qualification Certificates" and other qualification certificates, due to the large gap, the requirements have been relaxed in specific practice, and PCR certificates are sufficie.

A related person who provides medical certificate rental services has also recently provided nucleic acid testing related servic.

She told Eight Points Jianwen that the average nurse's certificate is 200 yuan a day, and the inspection of a full set of relevant certificates is "7,000 yuan for three month.

Several practitioners told Badianjianwen that the collection and inspection work is very mature and standardized, "equivalent to a mechanic", but the laboratory must also improve the intensity of quality contr.

If the experts who have been engaged in nucleic acid testing for two years cannot guarantee the quality of testing, then a large number of new personnel who have been rushed to work will inevitably go through a relatively chaotic adaptation peri.

Who should pay for the additional cost?

On May 25, the Office of the National Medical Security Administration and the Medical Treatment Team of the Joint Prevention and Control Mechanism of the New Coronavirus Pneumonia Epidemic of the State Council issued the "Notice on Further Reducing the Prices of New Coronavirus Nucleic Acid Testing and Antigen Testing" (hereinafter referred to as the "Notice"), requiring "all The province should reduce the single-person inspection to no more than 16 yuan per person; the multi-person mixed inspection will be reduced to no more than 5 yuan per pers.

”

The "Notice" also requires, "For the large-scale screening and normalized testing of government organizations, the scale effect and the cost-sharing effect of grassroots organizations and volunteers must be fully consider.

The standard billing is 5 yuan per person, and if the testing agency only provides sample transfer and testing services, the billing standard needs to be further reduc.

” The mixed mining price in Anhui, Beijing and other provinces is 4 yuan per pers.

For small-throughput laboratories, cost and quality are at sta.

According to Lilac Garden, after a laboratory selected a certain rapid test reagent with a "relatively high false positive rate", the time for results was increased from 4 hours to 1 hour, and the company's production capacity increased by 4

And "integration of collection, transportation and inspection" requires new investme.

Eight points Jianwen learned from industry insiders that two samplers at a sampling point in the industry are 50 yuan per person per hour, and auxiliary personnel are 28 yuan per hour, extracting reagents and amplifying The cost of reagents is about 4 yuan, and each set of sampling tubes and throat swabs is about 3 to 35 yu.

In addition, there is equipment lo.

"The ultra-low price model is not sustainab.

"

Tripartite testing agencies are experiencing a crisis of confiden.

On May 27, on the day of the Jinzhun Medical Incident, Beijing's Yanqing District announced that "all nucleic acid testing samples in the region will be tested by public medical institution.

In addition, many public hospitals and third-party institutions have reported to Badian Jianwen that the settlement of nucleic acid testing funds was not time.

"The county responded to the call to do a large screening, but no one asked for the mon.

After the official announcement of the refusal of medical insurance and the payment of normalized nucleic acid by local governments, on May 28, Sichuan Langzhong announced the implementation of normalized nucleic acid testing at their own expen.

, the government can't afford it, it can't be one size fits all, we just implement the order", after causing controversy, on the evening of the 29th, the local issued a document to "voluntary testing" by residen.

Beyond the four corners, the temporal and spatial distribution of normalized nucleic acid testing resources is also related to the rhythm of life of hundreds of millions of citizens, "Whether a new sampling point is unattended or will be overloaded, whether the concentrated work time is morning or evening, return to In which interval the volunteers will be matched, and how to adapt the sampling and laboratory operation to the rhythm of citizens' life and work, these are still unkno.

" The multi-party running-in of personnel, laboratories, information systems, and related departmen.