Supposed pituitary-production of human chorionic Gonadotropin induced by androgen deprivation therapy

ABSTRACT Introduction: The main cause of slightly elevated human chorionic gonadotropin (HCG) after successful treatment of male germ cell tumors is considered to be pituitary-derived HCG. It is well known that pituitary-derived HCG is frequently detected in postmenopausal women. We evaluated the status of serum HCG in men with elevated gonadotropins, which were induced by androgen deprivation therapy, using commercially available assays. Materials and Methods: We enrolled 44 patients with prostate cancer, who underwent luteinizing-hormone releasing hormone agonist treatment. We measured serum follicle-stimulating hormone (FSH), serum luteinizing hormone (LH), serum total HCG, serum free HCG-β subunit, and urine total HCG 3 times per patient, on the day of treatment initiation, the next day, and 3 months after. Results: On the day after treatment initiation, serum and urine HCG was detected in 61% and 73% of patients, respectively. Markedly strong correlations were observed between serum/urine HCG and FSH/LH. In particular, receiver operating characteristic curve analysis indicated excellent area under the curve (0.977, 95% confidence interval 0.951-1.003)) for serum HCG-detectable LH. At the cutoff value of 21.07 mIU/mL for serum HCG-detectable LH, the sensitivity and specificity were 96.7% and 95.3%, respectively. Serum HCG-β was not detectable at any times in any patients. Conclusions: Suggested pituitary-derived HCG can be frequently detected in patients with elevated gonadotropins, and there is a firm association between HCG detection and gonadotropin levels.

Análise comparativa da acurácia in vitro de testes de detecção de hCG urinário / Comparative analysis of the accuracy of urinary hCG tests in vitro

OBJETIVO: Identificar se os pontos de corte de sensibilidade anunciados por três testes de gravidez na urina são compatíveis com os anunciados pelo fabricante e descrever os seus desempenhos diagnósticos. MÉTODOS: A urina de um voluntário masculino foi usada para diluir β-hCG recombinante em concentrações definidas de 0; 6,25; 12,5; 25; 50; e 100 mUI/mL. As amostras foram codificadas e cegamente analisadas para a positividade em três diferentes lotes dos testes hCG Strip Test Plus®, BioEasy® e Visitect Pregnancy®. O tamanho da amostra foi calculado para um erro alfa de 5 por cento, com um poder de 99 por cento. RESULTADOS: As três marcas apresentaram sensibilidade de 100 por cento na detecção do β-hCG nos três lotes analisados, com 100 por cento de valor preditivo negativo, usando somente controles negativos e amostras com concentrações iguais ou superiores ao limite do teste (n = 180/marca). A acurácia dos testes foi 83 por cento (BioEasy®), 84 por cento (Visitect®) e 91 por cento (Strip Test Plus®). O Strip Test Plus® apresentou o melhor desempenho para a razão de probabilidade positiva (52,5), enquanto que o produto Visitect® teve a melhor razão de probabilidade negativa (zero). CONCLUSÃO: Os três produtos analisados têm a sensibilidade dos pontos de corte anunciados. O produto Strip Test Plus® tem o melhor desempenho para identificar concentrações urinárias de β-hCG > 12,5 mUI/mL, consequentemente, confirmando gravidez, enquanto que o Visitect® tem o melhor desempenho para descartar a presença de β-hCG na urina (probabilidade pós-teste negativo: zero).

OBJECTIVE: To identify whether cutoff for sensitivity advertised by three pregnancy tests in urine are compatible to those reported by the manufacturer and to describe their diagnostic performance. METHODS: The urine of a male volunteer was used to dilute recombinant β-hCG at defined concentrations of 0, 6.25, 12.5, 25, 50, and 100 mIU/mL. The tubes containing each of the concentrations were coded and blindly assessed for positivity in three different lots of hCG tests: Strip Test Plus®, BioEasy®, and Visitect Pregnancy®. The sample size was calculated for an alpha error of 5 percent, with a power of 99 percent. RESULTS: All three brands, in their three lots analyzed, had 100 percent of sensitivity for detecting β-hCG, with 100 percent negative predictive value, using only negative controls and samples with concentrations equal or higher than the test cutoff (n = 180/brand). The accuracy of the tests was 83 percent (BioEasy®), 84 percent(Visitect®) and 91 percent (Strip Test Plus®). Strip Test Plus® had the best positive likelihood ratio (52.5), while Visitect® had the best negative likelihood ratio (zero). CONCLUSION: The three brands have adequate sensitivity for the advertised cutoffs. The Strip Test Plus® test had the best performance to identify urinary concentrations of β-hCG > 12.5 mIU/mL, and consequently, to confirm pregnancy, while Visitect® had the best performance to exclude β-hCG in urine (negative post-test probability: zero).