The usefulness of testosterone administration in identifying false-positive elevation of serum human chorionic gonadotropin in patients with germ cell tumor

Objective: The pituitary production of human chorionic gonadotropin (hCG) can cause false-positive results during or after germ cell tumor (GCT) treatment. Because hypogonadism leads to pituitary hCG production, testosterone administration test (TAT) has been recommended for pituitary hCG diagnosis. However, little is known about its efficacy for the discrimination of pituitary hCG as detected by currently used hCG assays in treatment of GCT. We conducted a retrospective multicenter study to determine the usefulness of TAT. Materials and methods: The study included 60 patients who underwent TAT for the discrimination of pituitary hCG. In principle, serum hCG levels were measured 1 week after testosterone enanthate administration (250 mg). When the serum hCG levels decreased below the normal upper range, the results of TAT were determined positive. In this case, the elevated hCG was considered to be derived from pituitary and not from GCT. Results: Serum hCG levels were normalized after TAT in 36 of 60 patients (60%). Before TAT, the hCG levels were below 1.0 IU/L in 13 patients (36%), 1.0–1.9 IU/L in 11 (31%), 2.0–2.9 IU/L in 7 (19%), and >3.0 IU/L in 5 (14%) of TAT-positive patients. Of them, 28 (78%) patients were successfully managed without further treatment with chemotherapy after TAT. Pituitary hCG was associated with higher levels of LH and not necessarily associated with low levels of testosterone. Conclusion: Determining the TAT status of patients was effective in discriminating pituitary hCG production.