The National Institute of Public Health's website uses cookies.Read more about the use of cookies in our privacy statement.The email address you register here will only be used to send out news alerts you have requested.You can terminate your alerts at any time and delete your email address by following the link in the alerts you receive.Read more about privacy at fhi.no.Here is information on the practical implementation of sampling for SARS-CoV-2.Here is information on the practical implementation of sampling for SARS-CoV-2.Personnel must use the following protective equipment when sampling:Both hand washing with soap and water and hand disinfection are effective methods for hand hygiene.Sampling carries the risk of coughing and vomiting.The patient should therefore have a paper handkerchief available to cover the mouth and nose.Gloves must be changed between each person sampled.Hand hygiene must be performed when changing gloves.Personnel can use the same face mask, visor and coat for repeated sampling.If the coat comes into contact with the person being sampled or the equipment is soiled (visible secretions or the like), the equipment must be replaced immediately.Mouthpieces must also be changed if it becomes damp from condensation so that it becomes uncomfortable to wear.During the break, the equipment is discarded / replaced and clean protective equipment is put on after the break.Follow the procedure for putting on and taking off protective equipment:When choosing a sampling location, it is important to assess the purpose of the test and whether there is an indication for differential diagnostics.The viral load of SARS-CoV-2 is greatest in the nasopharynx (deep nose sample), but it is sufficient for most purposes also in the anterior nose and in the pharynx.In general, one should choose the least invasive sampling method that is acceptable for the purpose.For clinically indicated diagnosis, tests should be taken from both the nasopharynx and the pharynx.When screening and testing for infection control (mild symptoms), testing from the anterior or anterior nose and throat is sufficient, even in adults.Proper sampling technique is important to obtain a representative sample material and it can be challenging, especially when sampling from the nasopharynx.Saliva samples or sampling from the anterior part of the nose or rear wall of the pharynx can often be easier to perform, but also require the correct sampling technique.The choice of sampling location must be adapted and assessed according to local conditions, available equipment, the patient's ability to perform, sensitivity goals, analysis capacity, need for other differential diagnostics and whether the laboratory to be tested can perform the analysis on the sample material.There may be different amounts of virus and other biological material in different sample materials.The choice of sample material must be clarified with the laboratory that will analyze the sample, in case of doubt see the laboratories' own user manuals.When using antigen rapid tests, refer to the instructions for use and description of self-sampling below.In case of pronounced symptoms / clinical purpose (cases where treatment / medical follow-up depends on test results):When screening and testing for infection control purposes (eg for mild symptoms, the few situations where regular testing is still recommended, or corona certificate testing), non-invasive sampling methods should be preferred:When confirming positive self-tests, the most sensitive sampling methods should be preferred to minimize the possibility of false negative confirmatory tests:* Thin swab: primarily for sampling the nasopharynx.This can also be used for sampling in the throat, but has a lesser degree of stiffness and absorbency than a thick swab.** Thick swab: primarily for sampling the throat.Due to the thickness, length and stiffness of the brush, it is less suitable for sampling the nasopharynx as it does not go deep into the nose.Bronchoalveolar lavage (BAL) or tracheal aspirate.Children may find sampling uncomfortable.It is therefore recommended that the anterior nasal sample or pharynx sample be used (for PCR) in most situations as this is easier to perform and is experienced as less uncomfortable.For clinical sampling (eg if more serious disease is suspected), a nasopharyngeal test is still recommended, possibly both a throat test and anterior nasal test if the nasopharyngeal test is not feasible.If a differential diagnosis is desired, a nasopharyngeal sample should be taken.The actual sample from the nose and throat is taken in the same way as in adults.When sampling children, it is recommended that the child sit on the lap of a safe adult (for example, mother or father).The child should sit with the body straight forward, so that the child sits well against the adult's abdomen and chest, and the adult can hold a firm hand on the forehead and the other hand over the arms of the child.In smaller children, parents can be allowed to perform the testing of children (under supervision) if it is easier for the child to tolerate.If sampling takes place in a car, the parent must take the child out of the car seat and into his lap.Diversion and safety of the child can contribute to a simpler sampling situation.It is important to ensure that children do not experience that the testing involves coercion, or is otherwise performed in a way that is perceived as traumatic for the child.Some people who have diseases such asOsler's disease can cause nosebleeds after a deep nose test, while others may find this sampling very uncomfortable.In these situations, the anterior nasal sample or pharynx sample should be used (for PCR), or the anterior nasal sample for rapid testing.To reduce the use of protective equipment, self-sampling may be an option.Healthcare professionals must consider whether the person can carry out the sampling themselves.Recommendations regarding the choice of sampling of the upper respiratory tract are the same if the person performs the sampling himself (See section above).Healthcare professionals can guide the patient, preferably observe the sampling and ensure further handling of the sample.Professionally taken tests for NAT should still be done for clinical tests or where the consequences of false negatives can have extra major consequences.We consider the knowledge base to be good enough for self-sampling with anterior nasal sample (FP) to be used in situations where the purpose of the test is primarily to prevent further infection.The anterior nasal sample for antigen testing has such a low sensitivity that it is not recommended for clinical purposes alone.When used as a screening of persons for infection control purposes, on the other hand, an anterior nasal sample with antigen test will be a good tool due to its good ability to detect infectious persons.In the current situation, it seems that the sensitivity of the anterior nasal sample alone may be somewhat reduced.By combining the anterior nasal sample with a pharyngeal sample, the tests are likely to work at least as well for the omicron.A sample from the nose for self-testing will still catch most infected people, but sampling from the throat (throat) and nose will probably catch a few more cases of the omicron variant.Some people experience early in the course of the disease to get a positive self-test when they test in the throat and nose, while the test is negative when they take the sample only from the nose.These observations are now also supported by studies [1-3] which show that sampling with a combined pharyngeal nasal sample for antigen rapid tests is likely to capture a few more infected individuals than a nasal sample alone.This is especially true the first few days you have symptoms.Most available antigen rapid tests are intended for analysis of sample material from the posterior (nasopharyngeal) or anterior nasal sample, but it seems that these also work well for combined sample from the throat and nose.The self-tests that are in use today are not CE marked for sampling from the throat (throat).When used beyond its intended purpose (throat / throat sampling), the manufacturer can no longer be held responsible if the test does not work as intended.Especially adults with symptoms can take a sample from both the throat and the nose when they do self-tests (with a sample from the throat first) so that the probability of catching infection is as high as possible.A nasal sample should be used alone if it is perceived as uncomfortable or difficult to test in the throat (throat).Smaller children should preferably still be tested with only a nose sample, as many children find it uncomfortable with throat samples.Follow the test instructions for sampling, but take a sample from the throat before using the same swab for nasal sampling (see procedure below).Swallow should not be tested alone.Sampling when it is also to be tested from the throat should be done in the morning before consuming food and drink, possibly at least 30 minutes after consuming food and drink, to avoid the test becoming false positive.Some foods and beverages have been shown to affect test results.There are several studies comparing samples taken from the anterior nasal sample (FP) to the nasopharyngeal sample (NP) to PCR, but not so many on antigen tests.Anterior nasal sample:The anterior nasal sample probably has a sensitivity of 89-95% compared to the NP sample when looking at only positive and negative answers (Kimberly E. Hanson 2020, Tsang et al. 2021).It is likely that the somewhat lower sensitivity is mainly due to a reduced ability to correctly identify SARS-Cov-2 in samples with very little viral RNA (Pinninti, Trieu et al. 2020).(Callahan, Lee et al. 2020) found that the lower limit of detection was about 10 times higher for FP than for NP samples (1000 versus 100 virus rna / ml).There is also some increased risk associated with sampling from the nasopharynx.In very rare cases, sampling can lead to treatment-requiring complications such as severe bleeding (Koskinen et al. 2021).The procedure also entails an increased risk of sneezing / coughing from the sampled person, which may constitute a risk of infection for people in the vicinity.When the main purpose of the test is to prevent infection, the anterior nasal sample is therefore probably a better sampling method than nasopharyngeal specimens for NAT analyzes. The fact that they are less uncomfortable makes them particularly suitable for children and people who are frequently sampled.The practical significance of slightly lower sensitivity is probably low when the purpose is infection detection.In clinical sampling, however, NP should still be the first choice.Based on studies on analytical sensitivity to antigen tests and anterior nasal sample, it is likely that one will get a lower limit for detection that is about 1000 times higher than for PCR on NP samples (100 times higher for antigen compared to PCR, (Perchetti, Huang et al. 2020) and 10 times higher for anterior nasal sample).This is not alarming considering that LOD will then be around 100,000, which is still well below what is found in infectious people (Cevik, Tate et al. 2020).Two studies with the antigen test Binax-Now (comparable to Abbot-Panbio as the same manufacturer and technology) examine clinical sensitivity of anterior nasal sample for Ag test against NP test for PCR and virus culture (Prince-Guerra, Almendares et al. 2021, Mckay et al. 2021).Sensitivity for Ag test overall was 52.5% -69%, with 64.2-82% for symptomatic and 35.8-52% asymptomatic.As with other studies, there is also a large difference in the amount of virus between symptomatic and asymptomatic that explains the difference in sensitivity.Attempts were made to culture PCR positive samples.Sensitivity for Ag test versus culture positive was 92.6% for symptomatic and 78.6% for asymptomatic for Prince-Guerra and 95% for McKay.Sensitivity in the early infection phase (forward ct> 30 by PCR) was 86% in McKay et al.Stohr, Zwart et al.2021 found a sensitivity for Roche antigen self-test of 80.1% in people with virus levels associated with possible infectivity.This indicates that the best Ag tests have a good ability to detect infectious people, also in the anterior nasal sample.Two studies from Lindner et.al.suggests that self-sampled FP is comparable to professionally taken NP sample when virus levels are relatively high.Sensitivity to FP was somewhat lower than NP (74-82% versus 79.5% -85%) (Lindner, Nikolai et al. 2020, Lindner, Nikolai et al. 2021).At virus levels above 10 million RNA copies / ml, the sensitivity was above 96% for both FP and NP.England has an ongoing validation process of antigen tests in various phases (Peto 2021).Preliminary data indicate that the antigen tests are good at detecting infectious individuals, but that the test properties may vary somewhat in relation to the experience of the person testing.It is probable that much of the difference here stems from the fact that less experienced test subjects more often interpret weak positives as negatives, but it is also possible that the actual sampling may play a role.Good info and training is therefore very important.Tsang, NNY, et al."Diagnostic performance of different sampling approaches for SARS-CoV-2 RT-PCR testing: a systematic review and meta-analysis."The Lancet Infectious Diseases.Koskinen, A., et al.(2021)."Complications of COVID-19 Nasopharyngeal Swab Test."JAMA Otolaryngol Head Neck Surg.McKay, SL, et al.(2021)."Performance Evaluation of Serial SARS-CoV-2 Rapid Antigen Testing During a Nursing Home Outbreak."Ann Intern MedStohr, JJJM, VF Zwart, G. Goderski, A. Meijer, CRS Nagel-Imming, MFQ Kluytmans-van den Bergh, SD Pas, F. van den Oetelaar, M. Hellwich, KH Gan, A. Rietveld, JJ Verweij, JL Murk, W. van den Bijllaardt and JAJW Kluytmans (2021)."Self-testing for the detection of SARS-CoV-2 infection with rapid antigen tests."medRxiv: 2021.2002.2021.21252153.Saliva is a suitable sample material for the detection of SARS-CoV-2 by NAT (eg PCR) methods, but it is unclear whether this sample material can also be used to detect other respiratory agents such as influenza.If saliva is to be used as sample material, it is only in those cases where the sample is to be analyzed for covid-19 and other differential diagnostics is not indicated.Saliva is currently not a suitable sample material for antigen testing.There is a slightly smaller amount of virus in saliva compared to a well-taken deep nose sample.Nevertheless, there are enough viruses present within the first week with symptoms to be able to detect the vast majority of people who are in an active phase of the disease and who may be contagious.It has been shown that saliva that is actively collected in the mouth and transferred to a tube gives far better results than saliva collected with a sponge or other absorbent materials.If saliva is to be used as a sample material, this must first be clarified with a testing microbiological laboratory to ensure that the analysis methods used will be able to handle saliva and that the tubes used for the collection are compatible with the equipment used at the relevant laboratory.FHI recommends that one set of airway samples be taken if a local laboratory tests for SARS-CoV-2.If no local laboratory tests for SARS-CoV-2 may require the submission of additional test kits (see Laboratory User Manual for updated information).The sample must be accompanied by the requisition of the relevant laboratory, where the requester's name and telephone number must be clearly stated.The requisition must also be filled in with an indication for testing, including clinical / epidemiological information that gives rise to suspicion of infection with SARS-CoV-2:The sample should be taken early in the course of the disease.In case of negative test, but still maintained strong clinical suspicion, sampling should be repeated.The sample should preferably be stored and transported cool at 4 ° C (wet ice or cooling block not directly adjacent to the sample), but the sample can also be sent at ambient temperature overnight if this is most convenient.In such cases, the sample must be kept cool until shipping begins.The sample is marked and packed as influenza samples (category B).The reference laboratory at FHI performs laboratory analyzes for SARS-CoV-2 in connection with monitoring and research.Many medical laboratories in Norway perform diagnostics when covid-19 is suspected.For further information about the diagnostic offer, please refer to the websites of the respective laboratories.Noklus has prepared an e-learning course for training personnel in sampling.Read more about the course:Callahan, C., R. Lee, G. Lee, KE Zulauf, JE Kirby and R. Arnaout (2020)."Nasal-Swab Testing Misses Patients with Low SARS-CoV-2 Viral Loads."medRxiv.Cevik, M., M. Tate, O. Lloyd, AE Maraolo, J. Schafers and A. Ho (2020)."SARS-CoV-2, SARS-CoV, and MERS-CoV viral load dynamics, duration of viral shedding, and infectiousness: a systematic review and meta-analysis."The Lancet Microbe.Hanson, KE, AP Barker, DR Hillyard, N. Gilmore, JW Barrett, RR Orlandi and SM Shakir (2020)."Self-Collected Anterior Nasal and Saliva Specimens versus Health Care Worker-Collected Nasopharyngeal Swabs for the Molecular Detection of SARS-CoV-2."Journal of Clinical Microbiology 58 (11): e01824-01820.Kimberly E. Hanson, AMC, Cesar A. Arias, Mary K. Hayden, Janet A. Englund, Mark J. Lee, Mark Loeb, Robin Patel, Abdallah El Alayli, Osama Altayar, Payal Patel, Yngve Falck-Ytter, Valéry Lavergne , Rebecca L. Morgan, M. Hassan Murad, Shahnaz Sultan, Adarsh ​​Bhimraj, Reem A. Mustafa (2020)."The Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19: Molecular Diagnostic Testing, IDSA, 12.23 / 2020."Kojima, N., F. Turner, V. Slepnev, A. Bacelar, L. Deming, S. Kodeboyina and JD Klausner (2020)."Self-Collected Oral Fluid and Nasal Swabs Demonstrate Comparable Sensitivity to Clinician Collected Nasopharyngeal Swabs for Coronavirus Disease 2019 Detection."Clinical Infectious Diseases.Lindner, AK, O. Nikolai, F. Kausch, M. Wintel, F. Hommes, M. Gertler, L. Krüger, M. Gaeddert, F. Tobian, F. Lainati, L. Köppel, J. Seybold, VM Corman , C. Drosten, J. Hofmann, J. Sacks, F. Mockenhaupt and CM Denkinger (2020)."Head-to-head comparison of SARS-CoV-2 antigen-detecting rapid test with self-collected anterior nasal swab versus professional-collected nasopharyngeal swab."medRxiv: 2020.2010.2026.20219600.Lindner, AK, O. Nikolai, C. Rohardt, F. Kausch, M. Wintel, M. Gertler, S. Burock, M. Hörig, J. Bernhard, F. Tobian, M. Gaeddert, F. Lainati, VM Corman , TC Jones, JA Sacks, J. Seybold, CM Denkinger and FP Mockenhaupt (2021)."SARS-CoV-2 patient self-testing with an antigen-detecting rapid test: a head-to-head comparison with professional testing."medRxiv: 2021.2001.2006.20249009.McCulloch, DJ, AE Kim, NC Wilcox, JK Logue, AL Greninger, JA Englund and HY Chu (2020)."Comparison of Unsupervised Home Self-collected Midnasal Swabs With Clinician-Collected Nasopharyngeal Swabs for Detection of SARS-CoV-2 Infection."JAMA Netw Open 3 (7): e2016382.Perchetti, GA, M.-L.Huang, MG Mills, KR Jerome and AL Greninger (2020)."Analytical Sensitivity of the Abbott BinaxNOW COVID-19 Ag CARD."Journal of Clinical Microbiology: JCM.02880-02820.Peto, T. (2021)."COVID-19: Rapid Antigen detection for SARS-CoV-2 by lateral flow assay: a national systematic evaluation for mass testing."medRxiv: 2021.2001.2013.21249563.Pinninti, S., C. Trieu, SK Pati, M. Latting, J. Cooper, MC Seleme, S. Boppana, N. Arora, WJ Britt and SB Boppana (2020)."Comparing Nasopharyngeal and Midturbinate Nasal Swab Testing for the Identification of Severe Acute Respiratory Syndrome Coronavirus 2."Clinical Infectious Diseases.Prince-Guerra, JL, O. Almendares, LD Nolen, JKL Gunn, AP Dale, SA Buono, M. Deutsch-Feldman, S. Suppiah, L. Hao, Y. Zeng, VA Stevens, K. Knipe, J. Pompey , C. Atherstone, DP Bui, T. Powell, A. Tamin, JL Harcourt, PL Shewmaker, M. Medrzycki, P. Wong, S. Jain, A. Tejada-Strop, S. Rogers, B. Emery, H. Wang, M. Petway, C. Bohannon, JM Folster, A. MacNeil, R. Salerno, W. Kuhnert-Tallman, JE Tate, NJ Thornburg, HL Kirking, K. Sheiban, J. Kudrna, T. Cullen, KK Komatsu , JM Villanueva, DA Rose, JC Neatherlin, M. Anderson, PA Rota, MA Honein and WA Bower (2021)."Evaluation of Abbott BinaxNOW Rapid Antigen Test for SARS-CoV-2 Infection at Two Community-Based Testing Sites - Pima County, Arizona, November 3-17, 2020."MMWR Morb Mortal Wkly Rep 70 (3): 100-105.Tan, SY, HL Tey, ETH Lim, ST Toh, YH Chan, PT Tan, SA Lee, CX Tan, GCH Koh, TY Tan and C. Siau (2020)."The accuracy of healthcare worker versus self collected (2-in-1) Oropharyngeal and Bilateral Mid-Turbinate (OPMT) swabs and saliva samples for SARS-CoV-2."PLOS ONE 15 (12): e0244417.Tu, YP, R. Jennings, B. Hart, GA Cangelosi, RC Wood, K. Wehber, P. Verma, D. Vojta and EM Berke (2020)."Swabs Collected by Patients or Health Care Workers for SARS-CoV-2 Testing."N Engl J Med 383 (5): 494-496.Wehrhahn, MC, J. Robson, S. Brown, E. Bursle, S. Byrne, D. New, S. Chong, JP Newcombe, T. Siversten, and N. Hadlow (2020)."Self-collection: An appropriate alternative during the SARS-CoV-2 pandemic."Journal of Clinical Virology 128: 104417.Saliva sample for testing SARS-CoV-2 infection, 1st update on diagnostic accuracy (fhi.no) Saliva sample for testing SARS-CoV-2 infection - a rapid review (fhi.no) The Sensitivity and Costs of Testing for SARS-CoV -2 Infection With Saliva Versus Nasopharyngeal Swabs: A Systematic Review and Meta-analysis - PubMed (nih.gov) Stability of SARS-CoV-2 RNA in Nonsupplemented Saliva https://wwwnc.cdc.gov/eid/article/27/ 4 / 20-4199_articleComparison of Saliva and Nasopharyngeal Swab Nucleic Acid Amplification Testing for Detection of SARS-CoV-2: A Systematic Review and Meta-analysis |Infectious Diseases |JAMA Internal Medicine |JAMA Network12.02.2022: Updated according to change in test recommendations 12.02.2022.04.02.2022: Recommendations on sampling location for confirmatory testing of positive self-tests.Advice on self-sampling in self-tests moved from side to antigen rapid tests.03.09.2021: Added sentence that emphasizes that coercion must be avoided.27.08.2021: Clarification that the recommended sample material for clinically indicated diagnostics is the nasopharynx ± throat, as this is the most sensitive sample material and allows for differential diagnosis.Clarification that the correct sampling technique is important in order to obtain a representative sample material, also when sampling from locations other than the nasopharynx, such as the anterior nose.11.08.2021: Changed areas of use for anterior nasal sample09.07.2021: Linguistic changes and clarifications.If in doubt about which sample material the local laboratory accepts, one should look up in the laboratories' own user manuals.02.07.2021: Clarified distinction between testing for screening purposes and those tested due to symptoms.16.06.2021: Anterior nasal sample is now the preferred sampling method for non-clinical samples.Some updates according to new knowledge.12.05.2021: Clarified that saliva samples are not suitable for antigen tests.03.05.2021: Clarification of procedure for anterior nasal sample.08.04.2021: Added sentence about sampling of parents under supervision, sentence about entry sampling is removed.29.03.2021: Added section on sampling in people who experience severe discomfort.09.07.2021: Linguistic changes and clarifications.If in doubt about which sample material the local laboratory accepts, one should look up in the laboratories' own user manuals.26.03.2021: Sample location for diagnostic purposes and screening purposes made clearer.05.03.2021: Saliva is included as sample material for SARS-CoV-2 detection.22.02.2021: Added some clarifications regarding sampling of children.12.02.2021: Added information about anterior nasal sample and self-sampling.New recommendations in relation to sampling of children.29.12.2020: "Surgical bandage" has been changed to "Medical bandage" in the chapter Advice when the service recipient has been confirmed infected with SARS-CoV-2.03.11.2020: Removed the phrase "Respiratory protection (FFP3, FFP2) should be used in aerosol generating procedures."in the section "Protective equipment during sampling".01.09.2020: All chapters except "Lower airways" have been updated.The main changes are linguistic to clarify the message around testing, as well as harmonize recommendations regarding sampling against other chapters in the corona guide.This has been prepared by the lab outbreak group.05.08.2020: Revised back.Removed the changes to the visor that were posted on July 8th.08.07.2020: Added clarification under "Protective equipment for sampling" that health personnel should use visors instead of goggles as it provides extra protection of the outside of the mouthpiece and the face in general.7.5.2020: Added to Nordland Hospital Bodø on the list of laboratories testing for SARS-CoV-25.5.2020: Changed text: Practical sampling of children.Updated with illustrations of conducting sampling.Update overview of laboratories testing for SARS-CoV-2.In addition to this, linguistic changes have been made to clarify the advice.Prepared by lab outbreak group.29.04.2020: Removed the emergency preparedness laboratory at FHI from the list of laboratories that test for SARS-CoV-2NB!Do not enter personal information.We do not respond to these feedbacks, but use them to improve our websites.National Institute of Public Health PO Box 222 Skøyen 0213 OsloTel: 21 07 70 00 E-mail: Folkehelseinstituttet@fhi.no Org no: 983 744 516 Emergency telephones