There are two procedures to administer the COVID-19 diagnostic test:
1. The first procedure is to pass a sterile, cotton-tipped swab through the nostril and into the nasopharynx. This is part of the pharynx that covers the roof of the mouth. The swab is quickly rotated and removed.
2. The second procedure is called an oropharyngeal swab test, which is also administered with a cotton-tipped swab. The swab is passed through the mouth until it touches the oropharynx. It is then quickly rotated and removed.
Islamic Jurists explicitly mention the standard of nullification of a fast as thus:
If something is taken intentionally during a fast from the deemed passageways (Manfaz e Motabar) such as the nose and mouth, and remains in the deemed cavities (Jauf e Motabar) such as the stomach, the fast would be considered null and void.
In the case of both the aforementioned tests, a swab stick is passed all the way through the oral and nasal passageways until it reaches the oropharynx and nasopharynx and is then withdrawn safely and completely after a few seconds. Therefore, both of the COVID-19 diagnostic tests do not nullify the fast when administered correctly. However, in the event that the test goes wrong and the cotton swab or a piece of cotton fall into the deemed cavity (in this case the stomach), the fast will be considered null and void. Hence, the fast will need to be kept again (qaḍāʾ) without penance (kaffārah) because the cotton ball does not categorize under “nutrition or medicine”.