Respiratory Specimen Collection

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 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.

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.

Respiratory Specimen Collection

A. Upper respiratory tract

Nasopharyngeal specimen (NP) collection /Oropharyngeal (OP) (throat) specimen collection (performed by a trained healthcare provider, only)

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.

Instructions for collecting an NP specimen (performed by a trained healthcare provider): 

Tilt patient’s head back 70 degrees.
Gently and slowly insert a NP 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 mini swab 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.
For a visual guide, see the Nasopharyngeal (NP) Specimen Collection Steps infographic pdf icon[13 MB, 2 page].

Instructions for collecting an OP specimen (performed by a trained healthcare provider):

Insert swab into the posterior pharynx and tonsillar areas.

Rub swab over both tonsillar pillars and posterior oropharynx and avoid touching the tongue, teeth, and gums.
Place swab, tip first, into the transport tube provided.
Nasal mid-turbinate (NMT) specimen (performed by a healthcare provider or the patient after reviewing and following collection instructions):

Use a tapered swab.

Tilt patient’s head back 70 degrees.
While gently rotating the swab, insert swab less than one inch (about 2 cm) into nostril parallel to the palate (not upwards) until resistance is met at turbinates.
Rotate the swab several times against nasal wall and repeat in other nostril using the same swab.
Place swab, tip first, into the transport tube provided.