A rational diagnostic approach to the "phantom hCG" and other clinical scenarios in which a patient is thought to be pregnant but is not.

The scenario in which a patient tests positive for human chorionic gonadotropin (hCG) in the absence of pregnancy can pose a diagnostic dilemma for clinicians. The term "phantom hCG" refers to persistently positive hCG levels on diagnostic testing in a nonpregnant patient and such results often lead to a false diagnosis of malignancy and subsequent inappropriate treatment with chemotherapy or hysterectomy. There remains a need for a consistent and rational diagnostic approach to the "phantom hCG." This article aims to review the different etiologies of positive serum hCG testing in nonpregnant subjects and concludes with a practical, stepwise diagnostic approach to assist clinicians encountering this clinical dilemma.

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.

[Persistent low hCG levels beyond pregnancy: report of two cases and review of the literature]. / Élévation faible d'hCG en dehors d'un contexte gravidique : à propos de deux cas et revue de la littérature.

Unexpected finding or persistence of low human chorionic gonadotropin (hCG) levels is not a rare situation. It requires a clinico-biological approach in order to avoid misunderstandings that could lead to inappropriate diagnostic or therapeutic attitudes. Beyond pregnancy, persistent low levels of hCG may be associated with various benign and malignant conditions, i.e. quiescent gestational trophoblastic disease (QTD), raised pituitary hCG or false positive elevation caused by circulating heterophile antibodies. We report the cases of two non-pregnant patients with low serum hCG. In the first case, hCG levels raised during several years following a spontaneous abortion. The likelihood of heterophilic antibodies interference was ruled out and extensive clinical investigation excluded the presence of a tumour. The diagnosis was QTD. In the second case, elevated hCG came to light as an incidental finding in a women with chronic renal failure and led the clinicians to question the laboratory. The cause was probably an increase in pituitary hCG consecutive to terminal renal failure. These cases illustrate the importance of understanding the biology of the hCG and the causes of its persistent low elevation, which are reviewed in this article. It is essential to demonstrate clinically the presence of a tumour in order to avoid unnecessary and ineffective chemotherapy and/or hysterectomy.