When collecting oropharyngeal swabs
Because of the need to accurately view the location of the pharynx, the sampler usually has to stand directly across from the patient and is at great risk of exposure. For respiratory infections, nasopharyngeal swabs are a better choice of specimen, and they are also recommended in the Pneumonia Treatment Protocol for Novel Coronavirus Infections (Trial Version 5).
My laboratory has been performing nasopharyngeal swab sampling and Bacillus pertussis isolation and culture. There are some details of the sampling practice that need attention, which hopefully will help reduce contamination of protective clothing, avoid infection of front-line sampling personnel, and increase qualified sampling.
When collecting a nasopharyngeal swab
It is not at all necessary for the sampler to stand directly across from the patient. Whether the patient is sitting or lying down, the right-handed person can stand on the right side of the patient, and the left-handed person can stand on his or her left side for the sampling operation. The advantage of standing in the lateral position is that if the patient has a cough, sneeze, etc., it can be avoided in time. After passing through the nostrils, the nasopharyngeal swab penetrates deeper than the coronal surface of the head or face, and reaches the posterior wall of the nasopharynx from the lower nasal passage with a sense of touching the wall. The nasopharyngeal swab enters the nasal cavity at a depth of approximately the distance from the tip of the nose to the earlobe.
The American Society for Microbiology Guidelines for the Delivery of Clinical Microbiology Specimens require that the nasopharyngeal swab be twisted on the nasopharyngeal mucosa and retained for 10-15 seconds and then removed. Children are less cooperative, and in practice, we generally remove the swab after 2-3 full twists and three to five seconds.
In addition to the depth of swab entry to be noted, it is especially important to note that it is always the habit of some people to let the patient fully tilt the head, bend the swab, and then sample it, thinking that only in this way will a qualified specimen be taken. In fact, the above practice is wrong. This will cause the swab head to stay in the incorrect position and the final sample obtained will not be a standardized nasopharyngeal swab specimen.
In pediatrics, the immobilization of the child is also important to obtain a competent specimen. In the seated position, the assistant or parent holds the child's legs between their legs, holds the child's arms and trunk across the body with one hand, and immobilizes the head with the other.
When the patient is lying down, the assistant is required to hold the child's arms from one side with both forearms, fixing them on both sides of the body and at the same time playing the role of fixing the child's trunk, with the hands from both shoulders upwards and fixing the child's head with the palms of both hands.
