Rapid insulin assay for intraoperative confirmation of complete resection of insulinomas.
BACKGROUND
Solitary insulinomas are usually the cause of organic hypoglycemia, whereas 13% to 24% of patients with hyperinsulinemia have multiple tumors or nesidioblastosis. Intraoperative glucose levels confirming complete excision have variable accuracy. Intraoperative insulin levels have been shown to predict operative outcome. The purpose of this study was to establish criteria for predicting operative success by using a new, rapid insulin assay as an intraoperative adjunct.


METHODS
Eight consecutive patients with organic hypoglycemia underwent pancreatic exploration. With an 8-minute immunochemiluminescent insulin assay, peripheral blood levels were obtained preoperatively, during resection, and at 5-minute intervals after surgical excisions. Operative findings and outcome were compared with intraoperative insulin/glucose ratios (I/G), glucose, and insulin levels.


RESULTS
By using the return of insulin levels to normal range and I/G ratios < or = 0.4 15 minutes after tumor(s) resection as criteria to predict operative success, 6 patients had their outcomes correctly predicted (5 true-positive and 1 true-negative). One patient with nesidioblastosis had a false-negative result. One could not be evaluated because of diazoxide medication. These criteria predicted postoperative absence of hypoglycemia with specificity of 100% and accuracy of 89%.


CONCLUSIONS
These 8-minute insulin assay and criteria can be a useful adjunct for intraoperative assurance of complete insulinoma resection and prediction of postoperative outcome.
Carneiro
Denise M
DM
Department of Surgery, University of Miami/Jackson Memorial, Miami, FL 33101-6310, USA.
Levi
Joe U
JU
Irvin
George L
GL
D000328:Adult; D000368:Aged; D001786:Blood Glucose; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000175:diagnosis / Q000601:surgery; D007328:Insulin / Q000032:analysis* / Q000097:blood; D007340:Insulinoma / Q000097:blood / Q000175:diagnosis* / Q000601:surgery*; D008163:Luminescent Measurements; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D010182:Pancreatic Diseases / Q000097:blood / Q000175:diagnosis / Q000601:surgery; D010190:Pancreatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000601:surgery*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin