The Role of Proinsulin and Insulin in the Diagnosis of Insulinoma: A Critical Evaluation of the Endocrine Society Clinical Practice Guideline
The Role of Proinsulin and Insulin in the Diagnosis of Insulinoma: A Critical Evaluation of the Endocrine Society Clinical Practice Guideline
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DOI：
10.1210/jc.2013-2182
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发表时间：
2013-12-01
影响因子：
5.8
通讯作者：
Gorden, Phillip
中科院分区：
文献类型：
--
作者：
Guettier, Jean-Marc;Lungu, Andreea;Gorden, Phillip
内容：空腹胰岛素浓度>= 3 μ IU/mL和空腹胰岛素原浓度>= 5 pmol/L被认为是诊断胰岛素瘤的有用临界值。目的：主要目的是评估空腹胰岛素浓度>= 3 μ IU/mL和空腹胰岛素原浓度>= 5 pmol/L的诊断性能。设计：该设计是一个病例对照系列。设置：患者：五十六例受试者，在2000年6月至2011年4月期间，48小时监督禁食呈阳性，患有胰岛素瘤。在同一时间段内，胰岛素瘤的诊断被排除在29名受试者谁经历了一个有监督的快速。干预：48小时有监督的快速。主要结果测量：主要结果的措施是血清胰岛素浓度和血浆胰岛素原concentration.Results：91%的胰岛素瘤的患者有一个测量的胰岛素浓度>= 5 μ IU/mL在快速结束。如果定义胰岛素抑制不充分的阈值降低到>= 3 μ IU/mL，则灵敏度增加到98%。病例组和对照组的中位（四分位距）空腹胰岛素原终点分别为100（53-270）pmol/L和6.8（4.2-12.0）pmol/L。空腹胰岛素原终末值>5 pmol/L不能区分病例和对照（59%假阳性率）。所有胰岛素瘤患者（敏感性100%）和对照受试者（特异性100%）的空腹胰岛素原浓度结束时>= 27 pmol/L。结论：使用当前胰岛素测定，9%的胰岛素瘤病例在胰岛素浓度低于5 μ IU/mL的情况下结束监督空腹。使用>= 3 μ IU/mL的阈值定义的胰岛素抑制不足增加了测试的灵敏度。胰岛素原试验的价值在于其独特的区分病例和对照的能力。胰岛素原浓度>= 22 pmol/L最能区分病例和对照。依赖于5 pmol/L的快速胰岛素原截止值的终点不会增加灵敏度，但会大大降低检测的特异性。
Context: An end of fast insulin >= 3 mu IU/mL and a proinsulin concentration >= 5 pmol/L have been suggested as useful cutoffs for the diagnosis of insulinoma.Objective: The main objective was to evaluate the diagnostic performance of an end of fast insulin concentration >= 3 mu IU/mL and an end of fast proinsulin concentration >= 5 pmol/L.Design: The design was a case-control series.Setting: The setting was a tertiary-care center.Patients: Fifty-six subjects with a positive 48-hour supervised fast had an insulinoma between June 2000 and April 2011. During this same time period, a diagnosis of insulinoma was excluded in 29 subjects who underwent a supervised fast.Intervention: 48-hour supervised fast.Main Outcome Measure: The main outcome measures were serum insulin concentration and plasma proinsulin concentration.Results: Ninety-one percent of the patients with an insulinoma had a measured insulin concentration >= 5 mu IU/mL at the end of fast. The sensitivity increased to 98% if the threshold to define inadequate insulin suppression was lowered to >= 3 mu IU/mL. The median (interquartile range) end of fast proinsulin was 100 (53-270) pmol/L for cases and 6.8 (4.2-12.0) pmol/L for controls. An end of fast proinsulin value of >5 pmol/L could not distinguish cases from controls (59% false positive rate). All patients with an insulinoma (sensitivity 100%) and none of the control subject (specificity 100%) had end of fast proinsulin concentration >= 27 pmol/L.Conclusions: Using a current insulin assay 9% of insulinoma cases end the supervised fast with an insulin concentration below 5 mu IU/mL. Inadequate insulin suppression defined using a threshold of >= 3 mu IU/mL increases the sensitivity of the test. The value of the proinsulin test lies in its unique ability to distinguish cases from controls. A proinsulin concentration of >= 22 pmol/L best discriminates cases from controls. Reliance on an end of fast proinsulin cutoff value of 5 pmol/L does not augment sensitivity but greatly reduces specificity of the test.