How is insulinoma diagnosed?
A standard supervised fasting test is usually carried out for diagnosis - basically this looks at insulin production over a
period of time following the last "meal" (usually glucose). The patient will typically be in hospital for this period of time. As we see in RPA, ultrasound examinations are also used.
The diagnosis is made by simultaneous measurements of blood sugar and insulin levels in the blood. A low blood sugar with a high insulin level confirms the diagnosis. Once the diagnosis made based on the biochemical analysis then the physician will perform further studies to detect the tumor in the pancreas.
Since most of these tumors are small, detection of the tumor in the pancreas may be difficult. Some of the studies that are performed to detect the tumor include a detailed CT scan, MRI, octreotide scan, and an endoscopic ultrasound.
An experienced surgeon often detects these tumors even where they are not seen on radiological testing prior to surgery. Imaging the pancreas during the surgery directly with an ultrasound detects the majority of these tumors.