Chevalier Benjamin, Bonnet Delphine, Lepage Come, Perrier Marine, Borson-Chazot Françoise, Abeillon Juliette, Delobel Jean Bernard, Jannin Arnaud, Hadoux Julien, Haissaguere Magalie, Lombard-Bohas Catherine, Walter Thomas, Chardon Laurence
Department of Nuclear Medicine, Lille University Hospital, Lille 59000, France.
School of Medicine, University of Lille, Lille 59000, France.
J Endocr Soc. 2024 May 23;8(7):bvae102. doi: 10.1210/jendso/bvae102.
Vasoactive intestinal peptide (VIP)-secreting tumors (VIPomas) are digestive neuroendocrine tumors in which the hormonal secretion is life-threatening. Biological confirmation is obtained by demonstrating an elevation in plasma VIP, usually using radioimmunoassay (RIA). In some cases, analytical interference is suspected. We developed 3 different techniques to detect interference in VIP RIA.
Three techniques were used: RIA after Sephadex column chromatography separation, RIA after polyethylene glycol precipitation, and I-labeled VIP binding test. We included patients with suspicion of false positive VIP (FPV) elevation. We then compared results with those of a group of "real," proven VIPoma (RV).
A total of 15 patients with FPV elevation and 9 RV patients were included. Interference was detected in all FPV patients vs none in RV. Clinical and biochemical parameters did not differ between FPV and RV patients, but VIP concentration in RIA was significantly higher in FPV patients than in RV patients (228 pmol/L vs 66 pmol/L, = .038). Using a I-labeled VIP binding test, median proportion of radioactivity in the pellet was significantly higher in FPV than in RV patients (53% vs 13%, < .0001). A 20.5% threshold presented excellent performances (sensitivity 100% [79.6-100], specificity 100% [70.1-100]).
We developed 3 different laboratory techniques to reveal interference in RIA VIP assays. The diagnostic performance of all 3 was excellent. These techniques must be employed in cases of discordance between VIP elevation and clinical presentation.
分泌血管活性肠肽（VIP）的肿瘤（VIP瘤）是消化性神经内分泌肿瘤，其激素分泌会危及生命。通常采用放射免疫分析法（RIA）测定血浆VIP水平升高来进行生物学确诊。在某些情况下，怀疑存在分析干扰。我们开发了3种不同技术来检测VIP RIA中的干扰。
使用了3种技术：葡聚糖凝胶柱色谱分离后的RIA、聚乙二醇沉淀后的RIA以及¹²⁵I标记的VIP结合试验。纳入怀疑VIP假阳性（FPV）升高的患者。然后将结果与一组“真正的”、已证实的VIP瘤（RV）患者的结果进行比较。
共纳入15例FPV升高患者和9例RV患者。所有FPV患者均检测到干扰，而RV患者均未检测到。FPV患者和RV患者的临床和生化参数无差异，但FPV患者RIA中的VIP浓度显著高于RV患者（228 pmol/L对66 pmol/L，P = .038）。使用¹²⁵I标记的VIP结合试验，FPV患者沉淀中放射性的中位数比例显著高于RV患者（53%对13%，P < .0001）。20.5%的阈值表现出优异的性能（敏感性100% [79.6 - 100]，特异性100% [70.1 - 100]）。
我们开发了3种不同的实验室技术来揭示RIA VIP检测中的干扰。这3种技术的诊断性能均优异。在VIP升高与临床表现不一致的情况下必须采用这些技术。
