False-Positive Serum Human Chorionic Gonadotropin (hCG) in a Male Patient with a Malignant Germ Cell Tumor of the Testis: A Case Report and Review of the Literature

Abstract

A 39-year-old male patient with a favorable prognosis stage IIB metastatic malignant germ cell tumor (GCT) and elevated pre-and postorchiectomy serum human chorionic gonadotropin (hCG) was treated with three courses of combination chemotherapy resulting in a rapid normalization of his serum hCG.Within 2 months after the cessation of chemotherapy, his serum hCG increased again, suggesting tumor recurrence. Pathological examination of the resected residual retroperitoneal lymph nodes revealed no vital tumor cells. Based on the further rise in his serum hCG and enlargement of mediastinal lymph nodes on computed tomography scan, the patient underwent second-and third-line chemotherapy, which did not result in normalization of his serum hCG. Reanalysis of stored serum samples with other immunoassays revealed that the elevated serum hCG levels collected before first-line chemotherapy were indeed elevated, but those collected after first-line chemotherapy were all falsely positive. Currently, the patient is still alive and disease free. This is the first report of a male cancer patient who received unneeded second-and third-line chemotherapy for relapse based on false-positive hCG results. We discuss the pitfalls of false-positive serum hCG measurements, including heterophilic antibodies, as in our IgA-deficient patient, and review the literature. The Oncologist 2008;13:1149 -1154

Granulosa cell tumor of the testis in a newborn

“…As far as we know, and based on a thorough bibliographic research, elevation of hCG is not observed in JGCT of the testis. The mild elevation detected in our case was interpreted as a false-positive result, as observed in other testis tumors 25. Similarly, the method of dosage using Siemens kit accepts several interferences as causing false-positive results mainly in the range of 10–50 mUI/L.…”

A Case With Immunoassay Interferences in the Measurement of Multiple Hormones

“…Likewise, Bancos et al (14) reported that 4% of all IGF-1 measurements were falsely elevated in their retrospective review. There are also reports of falsely elevated ␤-hCG; the USA hCG Reference Service had identified 71 women with false-positive ␤-hCG results in their analysis, some of whom received unnecessary chemotherapy or surgery due to misdiagnosis of malignancy (15)(16)(17). Assay interferences reported for other hormones are mostly anecdotal.…”

Interference of luteinizing hormone in the urinary point-of-care human chorionic gonadotropin test

“…A previous report showed false positivity induced by mucus in patients with enterocystoplasties. False positivity is less common than false negativity; moreover, false positivity due to LH is very rare [ 3 ]. Because misdiagnosis of pregnancy can have important consequences and recognizing the possibility of interference is important to prevent critical misdiagnosis, we report this rare case with LH interference in urinary POCTs for hCG that showed different results according to lot number and manufacturer.…”