Sampling from the mucosal surface of the respiratory tract with a nasopharyngeal swab is a method used to diagnose neo-coronavirus in adults and children. This method is also commonly used to evaluate patients with suspected respiratory infections caused by other viruses and certain bacteria.

There are no clear contraindications to collecting specimens with nasopharyngeal swabs. However, clinicians should exercise caution if the patient has had recent nasal trauma or surgery, has a significant nasal septal deviation, or has a history of chronic nasal obstruction or severe coagulation disorders.

Preparation and equipment

Nasopharyngeal swabs are specially manufactured to have a long, flexible shaft made of plastic or metal and a tip made of polyester, rayon, or flocked nylon. In addition to the nasopharyngeal swab, you will need personal protective equipment (PPE), including a gown, non-sterile gloves, and a protective mask and face shield, as described below. Before beginning the procedure, ensure that all sample tubes are labeled and that the appropriate request form is completed.

You must follow the relevant respiratory and exposure precautions prescribed by the Centers for Disease Control and Prevention (CDC) and your own institution, and wear PPE properly. if possible, you should put on and take off PPE in the presence of an observer to ensure that there are technically no interruptions that could pose a risk of contamination.

First, put on protective clothing, wash your hands with soap and water (or with alcohol), and put on a pair of non-sterile gloves. Then wear a protective face shield of N95 or higher, as recommended by the CDC. Finally, put on a face and eye protection mask.

Procedure

A mask is recommended for all patients suspected of having a new coronavirus. Have the patient remove the mask and wipe the nose with a paper towel to remove excess nasal secretions. Remove the swab from the package. Tilt the patient's head back slightly so that the nasal passages are more accessible. Have the patient close their eyes to reduce the slight discomfort caused by the manipulation. Gently insert the swab along the nasal septum into the nasopharynx until resistance is felt.

Insert the swab into the nostril parallel to the palate. If you detect resistance to swab passage, back off and retry reinsertion at a different angle, near the base of the nasal cavity.

The depth of the swab should be equal to the distance from the nostril to the external opening of the ear. The CDC recommends leaving the swab in place for a few seconds to absorb secretions, then slowly removing the swab while rotating it.

Your institution may also recommend rotating the swab several times before removing it. Ask the patient to reapply the mask.

Open the specimen bag

Open the collection tube and insert the swab into the tube. Break the swab at the notch and discard what is left of the swab. Close the labeled collection tube and place it in the biohazard bag. In accordance with institutional practice, you may repackage the sample in its original packaging for shipping. Handle the swab sample directly according to CDC instructions, or place the swab in media with or without refrigeration.

Removal of Personal Protective Equipment

Remove personal protective equipment according to the standards of your institution. First, remove your gown and gloves. Wash your hands with alcohol or soap and water. Put on a new pair of gloves, then remove your face shield and either dispose of it or clean and store it at your institution according to the guidelines. Remove your gloves, rewash your hands, and put on another pair of gloves; then remove your mask and dispose of or reuse it according to your institution's guidelines. Finally, remove the last pair of gloves and wash your hands.