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Interim Guidelines for Collecting and Handling of Clinical Specimens for COVID-19 Testing
COVID-19 Testing -Key Points
The type of specimen collected when Testing for current or past infection with SARS-CoV-2 is based on the test being performed and its manufacturer’s instructions.
For the preliminary diagnostic test of current sars-cov-2 infection, CDC recommends collecting and testing upper respiratory tract specimens.
The compass is for health care institutions or health sector staff who are nursing from other health care institutions or at sample collection sites. A guide to self collecting specimens can be found here.
COVID-19 Testing : Collecting and Handling Specimens Safely
For healthcare providers collecting specimens or working within 6 feet of patients suspected to be infected with SARS-CoV-2, maintain proper infection control and use recommended personal protective equipment (PPE), which includes an N95 or higher-level respirator (or facemask if a respirator is not available), eye protection, gloves, and a gown.
For healthcare providers who are handling specimens, but are not directly involved in collection (e.g. handling self-collected specimens) and not working within 6 feet of the patient, follow Standard Precautions. Healthcare providers should wear a form of source control (face mask) at all times while in the healthcare facility.
Healthcare providers can minimize PPE use if patients collect their own specimens while maintaining at least 6 feet of separation.
COVID-19 Testing : Respiratory Specimen Collection
Respiratory specimens should be collected as soon as a decision has been made to test someone, regardless of the time of symptom onset. The guidance below addresses options for collecting specimens.
Proper specimen collection is the most important step in the laboratory diagnosis of infectious diseases. A specimen that is not collected correctly may lead to false or inconclusive test results. The following specimen collection guidelines follow standard recommended procedures.
For initial diagnostic COVID-19 Testing for current SARS-CoV-2 infections, CDC recommends collecting and testing an upper respiratory specimen. Contact the testing laboratory to confirm accepted specimen types and follow the manufacturer instructions for specimen collection. Sterile swabs should be used for the collection of upper respiratory specimens. This is important both to ensure patient safety and preserve specimen integrity. Note that nasopharyngeal and oropharyngeal specimens are not appropriate for self-collection.
COVID-19 Testing lower respiratory tract specimens is also an option. For patients who develop a productive cough, sputum can be collected and tested for SARS-CoV-2 when available. However, the induction of sputum is not recommended due to the possibility of aerosol production during the procedure. Under certain clinical circumstances (e.g., for those receiving invasive mechanical ventilation), a lower respiratory tract aspirate or bronchoalveolar lavage specimen can be collected and tested as a lower respiratory tract specimen.
A. Upper respiratory tract
Nasopharyngeal specimen (NP) collection /Oropharyngeal (OP) (throat) specimen collection (performed by a trained healthcare provider, only)
Illustration: swab inserted into nasal cavity
Use only synthetic fiber swabs with thin plastic or wire shafts that have been designed for sampling the nasopharyngeal mucosa. Do not use calcium alginate swabs or swabs with wooden shafts, as they may contain substances that inactivate some viruses and may inhibit molecular tests.
CDC recommends collecting only the NP specimen, although an OP specimen is an acceptable specimen type. If both NP and OP specimens are collected, combine them in a single tube to maximize test sensitivity and limit use of testing resources.
COVID-19 Testing : Instructions for collecting an NP specimen (performed by a trained healthcare provider):
Tilt patient’s head back 70 degrees.
Gently and slowly insert a minitip swab with a flexible shaft (wire or plastic) through the nostril parallel to the palate (not upwards) until resistance is encountered or the distance is equivalent to that from the ear to the nostril of the patient, indicating contact with the nasopharynx.
Gently rub and roll the swab.
Leave swab in place for several seconds to absorb secretions.
Slowly remove swab while rotating it. Specimens can be collected from both sides using the same swab, but it is not necessary to collect specimens from both sides if the minitip is saturated with fluid from the first collection.
If a deviated septum or blockage create difficulty in obtaining the specimen from one nostril, use the same swab to obtain the specimen from the other nostril.
Place swab, tip first, into the transport tube provided.