Why is covid pcr test taking so long – none:.Understanding The PCR Test and How There Was Never a Reliable Test for Covid
Dec 27, · The insider at a pathology unit at a hospital detailed why it is taking so long to process PCR tests for Covid and lifted the veil on how torturous it Author: Ash Cant. Dec 28, · A PCR Tester Has Lifted The Lid On Why You’re Waiting Ages For A COVID Test Result. A pathology worker has spilled the beans on why PCR test results are taking ages to arrive and the prognosis. Aug 07, · COVID rapid result testing can give you an answer in an hour – but that’s if the testing location has enough people to read the tests while you wait. If you’re at a location or clinic where hundreds of people are lined up for rapid result testing, then the wait itself may take longer than an hour, not to mention how long it might take.
This policy is taken as an adjustment due to the improvement of COVID in Indonesia. This policy comes into effect on and replaces. But not so with the common people. Rapid test, swab, and PCR are terms used in medical examination methods to detect Covid in a person’s body. One big misconception is that the swab is analyzed right at the point of collection. That’s usually not true — with some rapid (and pricey) PCR.
However, gains in speed are associated to a certain loss in accuracy. Some studies Chartrand et al. Several companies run these types of tests.
Once a patient has recovered, the virus is eliminated from the patients’ body and the molecular tests can no longer tell whether that person had been previously infected. Knowing both who has had the disease, and what proportion of the population has immunity, are both potential key pieces of information in managing the spread of the disease without widespread lockdowns.
The development of an antibody response to infection may still take some time and it may be host dependent i. This means that, unlike molecular tests, serologic tests are not suitable to identify who should be in isolation to avoid spreading the disease.
Immunologic testing can be done via two different techniques: ELISA enzyme-linked immunosorbent assay and immunochromatographic assays also known as lateral flow tests, such as those used for birth pregnancy test see Table 1.
A negative test does not therefore rule out the possibility that an individual has been infected, and vice-versa. The interpretation of these tests requires a substantial amount of further analysis before they can be considered ready for utilisation at scale.
Despite this, some regulatory authorities have recently changed their guidance to allow the launch of tests without approvals, so long as they are not used as the sole diagnostic. A further 64 manufacturers have notified the agency that they have validated similar tests and may market them in the near future. The FDA will not oppose the entry into the market of these tests 3 , but will only review the tests offered if companies request an Emergency Use Authorization.
However, the CE IVD marking does not necessarily mean that those products will immediately be available to purchase on the EU market as the manufacturer may decide to market them in countries outside the EU, or there may not be distributors selling these devices in all Member States European Centre for Disease Prevention and Control.
Detection of the virus presence in the organism. Detection of the immune response to the virus. Immunochromatographic assays rapid tests. Looks for the presence of viral genetic material RNA in a sample taken from the patient usually a nasopharyngeal swab. Looks for the presence of viral antigens in a sample taken from the patient. What does a positive test mean? The virus is present in the patient. The patient has been exposed to the virus and is either recovering or has already recovered.
First, strong and effective testing, tracking and tracing TTT, Section 3. If implemented properly, TTT is the most promising approach in the short-run to bringing — and keeping — the epidemic under control without resorting to widespread lockdowns of social and economic life. This sort of approach also provides key intelligence on the spread of the epidemic. Second, serologic tests among targeted priority population groups e.
Potentially, this approach could also be extended to cover more of the population, assisting in restarting economic activity Section 3. Third, once rapid serologic tests are reliable enough for utilisation at large scale, widespread testing will allow the estimation of how far away we are from herd immunity in the population.
This is crucial information to inform how to adjust social distancing measures Section 3. An effective strategy that tests suspected cases, tracks people infected and traces their contacts TTT will help to reduce the spread of the Coronavirus virus.
The approach of testing, tracking and tracing TTT has become a central tool for achieving this objective as many countries have decisively implemented it or are in the process of scaling it up.
The TTT approach may be used to block the initial or recurrent spreads of a pathogen, aiming for a rapid extinction of local, well defined outbreaks that collectively can control an epidemic. For diseases where infectiousness begins simultaneously with at the onset of symptoms, TTT can be very effective. Therefore, for the TTT strategy to be effective, contact tracing should be extended to some days before the onset of symptoms in every diagnosed patient; implementation needs to be at large scale, which poses a number of problems particularly in large countries; and it needs to be implemented quickly, to minimise the lag between the onset of symptoms and isolation of infected cases.
Box 2 describes their TTT strategies in more detail. Fast molecular tests can be used as confirmatory, becoming a very good alternative to RT-PCR tests to speed up and ease testing procedures. In the case of SARS-Cov2, expanding testing to asymptomatic or pre-symptomatic cases such as people who have been in contact with a confirmed case is particularly important, given the delay until the onset of symptoms.
Tracking: identifying where people infected are, in order to provide the most appropriate management of the case, and to prevent further spreading of the virus. Accurate tracking of infected patients and monitoring of compliance with isolation measures is key to limit contagion.
This also implies following-up of the contacts to monitor for symptoms and signs of infection, and testing then to check for disease infection.
A recent outbreak modelling study Hellewell et al. For instance, the majority of scenarios with a reproduction number or ability to spread of the virus, so-called R0 of 1.
The probability of control decreases with long delays from symptom onset to isolation, fewer cases ascertained by contact tracing, and increasing transmission before symptoms. This would require a huge increase in testing. The main purpose is to find and suppress as much as possible the local outbreaks across territories, which will require continuous effort to conduct effective TTT.
In addition, TTT helps monitor the evolution of the epidemic, since effective testing and digitally-enabled contact tracing allows the disease spread to be tracked. Combined with other health system information e. Testing: as of 6 April , Korea had conducted almost ten RT-PCR tests per thousand inhabitants, only behind Germany and Italy among countries with populations over 50 million 2. This pattern can be explained by a mix of strategic, logistic, capacity, regulatory, and even cultural considerations.
Korea developed a strong infrastructure for test kit production, distribution and laboratory analysis, after a strategic early decision to track most possible cases very strictly. Tracking: after testing suspected cases, the ones testing positive are tracked and provided with treatment free of charge. The cost is covered by central and local governments and the health insurance public corporation.
Korea also provides a subsidy to individuals who need to be isolated both self-isolation and hospitalisation to support their living costs and penalises those who are suspected to be infected if they refuse to receive diagnostic test, subsequent treatment or go through self-isolation.
People ordered into self-quarantine must download a mobile phone application, which alerts officials if a patient breaks isolation. All these tools allow for an effective tracking of patients. Tracing: Korea has developed a diverse digital crowd-sourced contact tracing strategy. Mobile phone locations are automatically recorded making possible to trace nearly everyone by following the location of their phones, which is facilitated by the fact that phone companies require all customers to provide their real names and national registry numbers.
The result of these tracing schemes are made public via national and local government websites, free smartphone apps that show the locations of infections, and text message updates about new local cases. Fines for quarantine violations can reach around EUR 2 A downside of this tracing system relates to privacy issues surrounding the measures, which may also prevent some infected people from coming forward OECD, .
Testing: Singapore initiated a large testing strategy for all suspected cases since the early days of the outbreak, reaching 2 tests RT-PCR a day for a population of 5.
Testing was deployed in primary care and hospital settings, and drive-through testing stations. In addition, people that died of a possible infectious cause and influenza-like illness were tested in sentinel clinics. Tracking: A network of more than public health preparedness clinics was activated in the primary care setting, with subsidies extended to residents to incentivise them to seek care, allowing to track many cases. Doctors were instructed to provide medical leave of up to five days for patients with respiratory symptoms, allowing them to quarantine at home.
All confirmed cases were immediately isolated in hospitals to prevent onward transmission. Treatment costs were borne by the government, including for patients from abroad. Tracing: All identified contacts presenting symptoms were referred to hospitals for isolation and testing, and then placed under 14 days quarantine from the last date of exposure.
To facilitate compliance and reduce hardship, the Quarantine Order Allowance Scheme provides economic assistance and the Infectious Disease Act provides legal power to enforce contact tracing and quarantine, and to prosecute those who do not comply penalties can be EUR 6 fine, six months jail, or both. Collaboration exists between public health officials, the armed forces and the police to trace people, for instance, using CCTV footage and data visualisation, conducting labour-intensive detective-like investigations.
The latter includes direct interviews with the patient and all identified contacts, calling them by phone requesting several details to determine their movement history seven days prior to symptom onset. Through in-person visits, a legal quarantine order is handed to each person. Investigation also includes receipts and card payments investigation to trace the movements of the infected person.
Accessed on 13 April 13 For example, supposing that the test could be administered to a large majority of people say every two weeks, it would be possible to isolate all those infected, and others could conduct a normal life. This would be enormously expensive, but the cost would nevertheless be trivial compared to the costs of lockdown. However, there are huge logistical challenges. In practice even with fast RT-PCR that can be administered at the point of care see Box 1 , it is unlikely that testing capacity will be sufficient for population-wide exhaustive testing.
This means that it is necessary for authorities to prioritise who should be tested. Testing strategies have to be feasible within the constraints of testing capacity and taking into account the transmission scenarios that are likely to occur. The WHO provides laboratory testing strategy recommendations specific to the number of cases an outbreak has reached in a country, between no and sporadic cases, to sustained community transmission WHO, .
In other words, there is a clear sequence of whom should be tested first, depending on the stage of the epidemic. Given the number of cases reached in most OECD countries at this stage, the priority for molecular laboratory tests will initially remain for ensuring safe and appropriate medical care, and therefore testing of hospitalised patients, vulnerable people who are likely to require hospital care and health care workers.
Once testing capacity is increased sufficiently, tests can be expanded to suspected non-severe cases and to people who were in contact with confirmed cases. This can allow targeted isolation of people who are infected, including those who show no symptoms.
Molecular tests are informative about whether a person is infected at the time of the test. As discussed above, RT-PCR-based tests represent the most accurate testing method but are also resource-intensive and capacity is therefore constrained.
Germany is an example where capacity for lab-based molecular tests was built early in the disease outbreak. Broad testing has allowed targeted isolation of confirmed cases, even if they were not symptomatic.
At the same time, vulnerable people who were infected could be hospitalised and received respiratory support before the onset of severe symptoms, increasing the odds of survival. These factors may have contributed to relatively low mortality in Germany, although a number of other factors also played a role, including that many of the people initially infected were relatively young and healthy. In the absence of reliable information about contacts between people who carry the virus and others, people at risk of being so-called super-spreaders can also be a priority group for repeated testing.
These are people who come into contact with many other people as part of their daily activities. Beyond health professionals, people working in supermarkets and grocery stores, public transport and in delivery services may be at higher risk of spreading the virus to many other people.
Serologic testing , which identifies antibodies produced by the human immune system can serve a different purpose. Their use requires that accurate serologic tests are available see above but in addition, ideally we would also want to understand better the immunological response, and its duration. For example, whilst it seems clear that having had the disease once confers some immunity, how long this immunity might last is unclear Petherick, .
Serologic tests can also be conducted in priority groups such as super-spreaders. There is a particular interest in the potential for serologic tests as part of a strategy to support restarting economic activity. Most obviously, testing health professionals would limit unnecessary self-isolation, and increase the capacity of the health sector. Beyond this, testing occupational groups who cannot telework during lockdowns; and priority segments of the workforce, to identify those already immune, may be useful in allowing more people to safely return to work.
In addition to targeted testing of priority groups, testing can also take place in random samples of people for estimating prevalence and assessing progress towards herd immunity, as discussed below.
People who have an immune response could be released from restrictions to movement, preferably in conjunction with a molecular diagnostic test to confirm that the person does not have an active infection. If new cases can be tracked and isolated effectively and transmission reduced, restrictions can also more readily be eased gradually for people who are not immune.
People who are not immune may seek to expose themselves to the virus in order to gain immunity and re gain a more normal life and work. This would be a very understandable response, given that many people have lost the chance to earn their living and support their families due to the lockdowns. Unfortunately, the risk of such behaviour is that the disease may start spreading very rapidly once again, with the possibility that health services are overwhelmed.
Herd immunity can be measured mainly in two ways Reid and Goldberg,  :. Indirectly from the age distribution and incidence pattern of the disease, if it is clinically distinct and reasonably common. Directly from assessments of immunity in defined population groups by application of serologic tests, as discussed above. The assessment of immunity at the population level also called sero-surveillance Wilson et al.
Into the future, sero-surveillance could provide relevant information to plan vaccination strategies, avoiding the need to vaccinate those who already have immunity. In other words, the effective reproduction number at a given point in time Rt in these circumstances is less than 1. These are also key parameters to decide to what extent restrictions e. As mentioned in Section 2. However, serologic tests’ reliability is still a major issue so governments are struggling to select the most appropriate one and are waiting for independent tests validations to come out.
Another relevant factor has to do with better understanding the characteristics and evolution of the virus itself. So far, researchers have found that the virus is quite stable and does not mutate significantly 8. However, this is another area where further research is desirable in order to inform policymaking. Herd immunity is dynamic and can be lost over time through waning of immunological memory or deaths of immune individuals, and newly susceptible individuals arrive through births or migration Reid and Goldberg, .
Evidence from a survivor from the original SARS-CoV infection in indicates that, 17 years later, the person still has antibodies which are capable of neutralising the virus Petherick, .
However, immunity can also be diminished if the virus changes, as happens with influenza where a new vaccine is required every year. Implementation of testing in OECD countries is varying rapidly.
As of 4 May , tests per 1 population in OECD countries varied from fewer than one to more than tests per 1 population see Figure 1. Notes: 1. People or cases tested. Tests performed or samples tested.
Units of test unclear or inconsistent. Differences exist as to whether figures include tests, or individuals tested; whether they include all lab tests public and private or not; on how regularly data is updated by each country; and other aspects. Date of testing data shown in the graph varies between 26 April and 3 May Source: Our World in Data. Successful implementation of testing strategies requires some practical problems to be overcome, and possible issues around data privacy to be addressed OECD, .
Testing for the Coronavirus has varied widely across countries. To reduce the risk of new outbreaks, countries will need to greatly increase their testing capacity.
There are several prerequisites for the feasibility of testing as a key element for the transition away from current lockdown measures.
These comprise scientific knowledge, planning demand for needed equipment and coordination in procurement, building capacity to execute tests, and managing information.
First, scientific research on immunity and how to test immunity needs to continue. It has to be entirely confirmed that immunity is indeed built for any person who got infected, and for how long such immunity lasts.
So far, assumptions about immunity are based on animal models Bao et al. As stated in Section 2. Second, governments need to make realistic projections about the equipment necessary to execute large-scale testing strategies and coordinate procurement at both national and international level. Demand projections and certainty about what will be purchased can help the manufacturing industry to build capacity. PCR-based tests require nasopharyngeal swabs for collecting samples, test kits with chemical reagents to isolate and prepare viral genetic material in the samples for analyses, laboratory machinery to conduct analyses, and protective equipment for personnel.
Throat — Some sites are getting samples from the throat. In most cases, a healthcare professional gets this sample. This helps to make sure that the sample is high quality. In all cases, staff are trained on the collection method used at their site and will help guide you on the process. The testing process takes between 5 to 10 minutes. Only those with confirmed appointments will be tested. All individuals in the car should be wearing appropriate face coverings.
If you do not have a car, you may make an appointment or visit any of the walk-up testing sites in LA County. To find the nearest walk-up testing location near you, use the map here. A parent or guardian will need to help with the test. If your child has new or worsening symptoms such as trouble breathing, pain or pressure in chest, feeling confused or having difficulty waking up, or blue-colored lips or face, call or seek emergency medical attention right away. Everyone 18 years of age and over should bring some type of personal identification to your test.
This helps ensure that your test results are matched to the right person. Your identity and test results are protected by federal law and will not be shared with any other agencies for purposes of law enforcement or immigration. It typically takes between 24 to 48 hours to receive your test results.
You will be notified by email, text, by phone call, and in some cases by mail, depending on the site. It is very important that you provide accurate and complete information when registering. We use this information to contact you with your results. While waiting for results, it is essential that you wear a mask and maintain social distance.
If you are sick, stay home and self-isolate until the test results are back. You should arrange for others to provide groceries, medicines, etc. If you do not have someone to help you, you can arrange for food and other necessities to be left at your door. If you need help finding food or other necessities, call , visit la. Even if the test is negative and you are experiencing symptoms, you should remain at home until any fever has resolved and any other symptoms have significantly improved.
If you are not improving, or feeling worse, contact your doctor or seek medical care. The County is not offering testing for employers seeking to test all employees, or for employers who wish to implement testing for employees coming back to work after a period of absence.
Employers who are interested in implementing this practice should work directly with a lab offering these services. If an employer requires routine or repeated testing, your employer should provide that test. The number of testing appointments vary by site depending on size and personnel available, between 50 to over 1, appointments per day. We work in partnership with the State, local jurisdictions, community partners, and the existing health system to establish a broad network of testing sites that offer free testing to all Los Angeles County residents who either cannot access testing with their healthcare provider or does not have a provider.
The County looks at the COVID mortality rates, positivity rates and testing rates in communities across the County to identify highest-need areas in order to expand testing or open new testing sites.
Your health care provider can talk with you about your concerns. If you do not have a doctor, call or visit the LA to get a referral. If you are not fully vaccinated and this test collected on or after Day 5 is negative, you can end quarantine after Day 7. School children who are under a modified quarantine must get tested twice—once as soon as possible after the exposure and the second at least 3 days later.
Screening testing is required if: It is required by your workplace. You visit places — including mega-events indoors at skilled nursing facilities , intermediate care facilities , and juvenile detention facilities , and indoors and outdoors at adult correctional and detention centers.
Screening testing may also be required by certain businesses and venues You are not fully vaccinated , and You work in a place where COVID vaccination is required. You are going to visit certain places, including mega-events , indoors at skilled nursing facilities , intermediate care facilities , and juvenile detention facilities , and indoors and outdoors at adult correctional and detention centers.
Screening testing may also be required by certain businesses and venues. You are a staff member or athlete in moderate- or high-risk organized youth sports, including school sports teams. Note: children under 12 years of age playing outdoor moderate- and high-risk sports are not required to test.
You are traveling by plane into the United States from another country even if you are fully vaccinated. Testing is also required before entering some other countries, check the rules before you plan your travel. Note: There may be other settings that have their own screening testing requirements. See Protocol for Organized Youth Sports for more details. You are traveling outside of California within the United States.
Testing is recommended days before and days after travel. See Travel Advisory. You are going to be attending an outdoor mega-event. Testing will be required effective October 7, You After returning from international travel , even if you are fully vaccinated For teachers and students in schools It is recommended that students get regular screening testing if not fully vaccinated. Unvaccinated teachers are required to get in regular screening testing. Exposures include: Being within 6 feet of an infected person for a total of 15 minutes or more within a hour period.
For example, being coughed or sneezed on, sharing utensils or saliva, or providing care without wearing appropriate protective equipment. What if I do not have internet access?