Most definitive diagnosis of sinusitis is:
X ray PNS
Proof puncture
Sinoscopy
Transillumination test
There are many possible methods to make diagnosis of rhinosinusitis but there is much debate related to best method. It has become increasingly clear that the diagnosis of ARBS is best made on clinical grounds and criteria. Ref Scott Brown 7/e,Vol 2,p 1142.
Nose and paranasal sinuses