COVID-19 testing is a common concern for parents when a child develops cold-like symptoms. Nasal discharge, often called “snot,” can indeed be used for testing, as nasal samples are the standard method for detecting an active COVID-19 infection in children. Testing is generally recommended when a child exhibits symptoms or following a known exposure. This quickly determines if isolation and other protective measures are necessary.
The Correct Way to Collect a Nasal Sample from a Child
At-home COVID-19 tests use an anterior nasal swab, collecting a sample from the lower part of the nostril. This process is much less invasive than the deep nasopharyngeal swabs performed by healthcare providers. Before starting, encourage the child to blow their nose to clear excess mucus and bring viral material forward. Always wash hands thoroughly and avoid touching the soft tip of the swab to prevent contamination.
The swab should be inserted gently into the nostril, typically no more than one-half to three-quarters of an inch, or about 1 to 1.5 centimeters, until a slight resistance is felt. Once inserted, the swab must be firmly rotated against the inside wall of the nostril at least four times for approximately 10 to 15 seconds to ensure adequate collection of the specimen. The entire process should be repeated in the second nostril using the exact same swab to maximize the viral material collected.
Ensuring a good sample requires keeping the child calm and cooperative. Use distraction techniques, such as counting to 15 or singing a short song. After collection, place the swab into the provided transport tube, which often contains a buffer solution. The swab stick must then be broken off at the designated line, and following the precise instructions is necessary for an accurate result.
Distinguishing Between Antigen and PCR Testing
The nasal sample collected from a child will be analyzed by one of two main types of diagnostic tests: the Rapid Antigen Test (RAT) or the Polymerase Chain Reaction (PCR) test. Antigen tests work by detecting specific proteins, known as antigens, that are present on the surface of the SARS-CoV-2 virus. These tests are popular for their speed, as they can usually deliver results within 15 to 30 minutes, making them suitable for quick decision-making.
Antigen tests, however, are generally less sensitive than PCR tests, meaning they are more likely to produce a false negative result, particularly early in the infection when the viral load is low. In contrast, the PCR test is considered the gold standard because it detects the virus’s genetic material (RNA) by repeatedly amplifying it, even if only a tiny amount is present in the sample. This molecular testing process is highly accurate and can detect the virus earlier in the infection timeline, although results typically take 24 to 48 hours to process in a laboratory.
Parents often choose the antigen test for initial screening or when immediate results are needed, such as before a family gathering or returning to school. Conversely, a PCR test is usually recommended to confirm an infection. This is especially true if an antigen test is negative but the child is symptomatic or has a known high-risk exposure.
Understanding and Acting on Pediatric Test Results
A positive test result, whether antigen or PCR, means the virus was detected and the child is currently infected and likely contagious. Even a very faint line on an antigen test should be interpreted as positive. The immediate action is to initiate isolation protocols to prevent further transmission. Public health guidance suggests children under 18 isolate for three to five days after the test date or symptom onset, provided symptoms are improving and they are fever-free without medication.
A negative antigen test result, especially in a symptomatic child, should be viewed with caution due to the test’s lower sensitivity and the possibility of a false negative. If the child has symptoms but tests negative, repeating the antigen test 48 hours later is often advised, as the viral load may have increased. Alternatively, a follow-up PCR test may be necessary to definitively rule out infection.
If a child’s symptoms worsen, such as developing a high fever lasting more than five days, breathing difficulties, or other concerning signs, medical attention should be sought immediately. For an asymptomatic child with a negative result after exposure, they should continue to monitor for symptoms for several days. Following the isolation or retesting guidelines provided by the child’s school or daycare is also an important part of the management plan.