Anti-goat antibodies as a rare cause of high gonadotropin levels during menopausal transition

Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2 months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173 ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.

Chinese abstract

目的：研究围绝经期女性超高促性腺激素水平的原因。

方法：一名52岁女性, 自然月经周期后闭经2个月, 来门诊就诊的原因是出现高水平的卵泡刺激素(FSH 483mUI/ml)、黄体生成素(LH 475 mUI/ml)和催乳素(PRL 173 ng/ml)。据了解她服用左旋舒必利。促性腺激素水平与临床特征不符。

结果：已经排除了促性腺激素肿瘤, 需要进一步分析证实FSH、LH和PRL水平持续升高的原因。使用不同的分析平台重复测量, 得到了不同的结果。经过连续稀释后, 出现非线性特征提示存在免疫测定干扰。在聚乙二醇处理后, 激素水平恢复正常。患者血清中可识别出抗山羊抗体。

结论:此病例显示一例女性在绝经过渡期出现假性高促性腺激素及高催乳素水平。在临床实践中, 不建议在这个年龄段评估促性腺激素水平, 但异常者要进一步进行评估。由于抗山羊抗体的干扰, 导致FSH和LH水平异常升高。当实验室结果与临床不一致时, 临床医生和检验科医生之间需要严格的协作。

Keywords:

• Menopausal transition
• gonadotropins
• anti-goat antibodies
• interfering antibodies

Author contributions

F.F conceived the project and designed the research. G.P analyzed the data and wrote the original draft. M.R.S and S.S performed biochemical assays, TS final revision. All authors reviewed and approved final version.

Disclosure statement

No potential conflict of interest was reported by the author(s).