Final answer:
Transillumination of the sinus cavity is a quick test that can be utilized to help rule out a sinus-related cause of a patient's headache and sniffling symptoms.
Step-by-step explanation:
A patient complains of a headache since the morning, is sniffling, and has been blowing their nose all morning due to "allergies". They also had a fall the previous evening but were wearing a helmet. Given this information, a quick test to help rule out a sinus-related cause of symptoms would be transillumination of his sinus cavity. This non-invasive procedure can help identify sinus blockages which may be contributing to the headache and nasal congestion. In contrast, a CT scan, while comprehensive, is not typically a first-line quick test because it is more expensive, involves radiation exposure, and would usually be reserved for more serious concerns or if initial testing does not provide answers. Urine dipstick of nasal discharge is not a relevant test, and culture and sensitivity (C&S) of the larynx would not be indicated in this case without symptoms of a laryngeal infection.