Human chorionic gonadotropin suspected heterophile interference investigations in immunoassays: a recommended approach

Human chorionic gonadotropin of pituitary origin in Chinese postmenopausal women: A single-center retrospective study

OBJECTIVE

We analyze the characteristics and related factors of human chorionic gonadotropin (hCG) of pituitary origin to establish the reference interval to resolve clinical confusion and avoid harmful therapy to Chinese postmenopausal women with "positive" hCG.

MATERIALS AND METHODS

This retrospective cohort study identified individuals who underwent hCG measurements at an academic hospital. Three gonadotropins (hCG, follicle stimulating hormone (FSH), and luteinizing hormone (LH)) was drawn from medical records. The age-stratified analyses were performed first. Then the correlations of hCG and FSH, LH as well as age were analysed. Finally, characteristics and associations of hCG, LH, and FSH were evaluated to identify pituitary hCG in postmenopausal women in clinical settings.

RESULTS

In total, 9796 cases from 11172 records met inclusion criteria and contributed 9796 hCG, 7541 FSH, and 7536 LH values. The upper reference interval for our cohorts was 5.3 IU/L. HCG, FSH, and LH concentration had no significant correlations with age. HCG moderately correlated with FSH (r = 0.47) and LH level (r = 0.53). However, it was FSH but not LH that manifested good clinical applicability.

CONCLUSION

The prevalence of hCG≥5.0 IU/L and 5.3 IU/L in women ≥55 years is 2.8% and 2.3% in the study population from China. The level of hCG 5.3 IU/L was suggested to be the positive threshold for postmenopausal women. FSH≥40IU/L helps to distinguish the pituitary source of hCG in postmenopausal women whose serum hCG concentrations were between 5.3 and 16 IU/L.

Persistently elevated serum concentrations of human chorionic gonadotropin (hCG)

OBJECTIVES

We describe a woman with constantly elevated hCG levels in serum. Since assay interference, pregnancy or cancer did not explain the elevated levels, we measured the concentrations of hCG, its β subunit (hCGβ) and its core fragment (hCGβcf) in serum and urine using specific assays, to understand the nature of the elevated hCG levels.

METHODS

We used 3 assays for total hCG (these assays also recognize hCGβ and to various degrees hCGβcf), 3 for intact hCG heterodimer, 3 for free hCGβ and one for hCGβcf.

RESULTS

With an hCG assay detecting total hCG the serum concentrations were in the range of 150-260 IU/L for the whole study period of almost 5 years, except for a peak of 1,200 IU/L, coinciding with a spontaneous abortion. Quantitation of different forms of hCG with specific immunoassays showed that the immunoreactivity in serum consisted of hCGβ. Urine contained hCGβ and hCGβcf.

CONCLUSIONS

The laboratory findings are in keeping with familial hCG syndrome. However, so far the condition remains to be determined in any family members. Elevated hCG levels without any explanation are problematic as they cause suspicion of cancer or ectopic pregnancy and may lead to harmful therapy. Specific assays, as used here, will aid in diagnosis of such cases.

First pre-filled pen device with highly purified human menopausal gonadotropin (HP-hMG, Menopur) in liquid is shown to be bioequivalent to powder for reconstitution

OBJECTIVE

To determine whether serum human follicle-stimulating hormone (FSH) levels after single subcutaneous dosing of highly purified human menopausal gonadotropins (HP-hMG) in a liquid formulation and a powder formulation are bioequivalent.

MATERIALS AND METHODS

This was a randomized, two-way, crossover, single-dose, bioequivalence trial comparing Menopur liquid injected by pre-filled pen, with Menopur powder injected by conventional syringe and needle. The primary endpoints were AUC_t and C_max of baseline-adjusted FSH. Pituitary-suppressed, healthy women were administered single subcutaneous injections of 450 IU Menopur liquid (600 IU/0.96 mL) and 450 IU Menopur powder (by 2 subcutaneous injections of 225 IU in 1 mL) in a randomized order. The pharmacokinetic parameters of FSH and human chorionic gonadotropin (hCG) were assessed by non-compartmental methods with adjustment for endogenous pre-dose levels.

RESULTS

In total, 76 women were randomized, and 56 completed the trial. The mean FSH and hCG serum concentration-time profiles were comparable between the two HP-hMG formulations. The geometric mean ratios and 90% confidence intervals of FSH for HP-hMG liquid versus HP-hMG powder were 1.12 (1.0562 - 1.1889) for AUC_t and 1.17 (1.0946 - 1.2490) for C_max, showing that the two formulations were bioequivalent. The incidence and severity of adverse events were similar between the two preparations, and both preparations were well tolerated.

CONCLUSION

The 90% CIs for the geometric mean ratios of serum FSH AUC_t and C_max were both within 0.8000 - 1.2500, thus the two formulations are bioequivalent.

Immunoaffinity Capillary Electrophoresis in the Era of Proteoforms, Liquid Biopsy and Preventive Medicine: A Potential Impact in the Diagnosis and Monitoring of Disease Progression

Over the years, multiple biomarkers have been used to aid in disease screening, diagnosis, prognosis, and response to therapy. As of late, protein biomarkers are gaining strength in their role for early disease diagnosis and prognosis in part due to the advancements in identification and characterization of a distinct functional pool of proteins known as proteoforms. Proteoforms are defined as all of the different molecular forms of a protein derived from a single gene caused by genetic variations, alternative spliced RNA transcripts and post-translational modifications. Monitoring the structural changes of each proteoform of a particular protein is essential to elucidate the complex molecular mechanisms that guide the course of disease. Clinical proteomics therefore holds the potential to offer further insight into disease pathology, progression, and prevention. Nevertheless, more technologically advanced diagnostic methods are needed to improve the reliability and clinical applicability of proteomics in preventive medicine. In this manuscript, we review the use of immunoaffinity capillary electrophoresis (IACE) as an emerging powerful diagnostic tool to isolate, separate, detect and characterize proteoform biomarkers obtained from liquid biopsy. IACE is an affinity capture-separation technology capable of isolating, concentrating and analyzing a wide range of biomarkers present in biological fluids. Isolation and concentration of target analytes is accomplished through binding to one or more biorecognition affinity ligands immobilized to a solid support, while separation and analysis are achieved by high-resolution capillary electrophoresis (CE) coupled to one or more detectors. IACE has the potential to generate rapid results with significant accuracy, leading to reliability and reproducibility in diagnosing and monitoring disease. Additionally, IACE has the capability of monitoring the efficacy of therapeutic agents by quantifying companion and complementary protein biomarkers. With advancements in telemedicine and artificial intelligence, the implementation of proteoform biomarker detection and analysis may significantly improve our capacity to identify medical conditions early and intervene in ways that improve health outcomes for individuals and populations.

Understanding and managing interferences in clinical laboratory assays: the role of laboratory professionals

The recently raised concerns regarding biotin interference in immunoassays have increased the awareness of laboratory professionals and clinicians of the evidence that the analytical phase is still vulnerable to errors, particularly as analytical interferences may lead to erroneous results and risks for patient safety. The issue of interference in laboratory testing, which is not new, continues to be a challenge deserving the concern and interest of laboratory professionals and clinicians. Analytical interferences should be subdivided into two types on the basis of the possibility of their detection before the analytical process. The first (type 1) is represented by lipemia, hemolysis and icterus, and the second (type 2), by unusual constituents that are not undetectable before analysis, and may affect the matrix of serum/plasma of individual subjects. Type 2 cannot be identified with current techniques when performing the pre-analytical phase. Therefore, in addition to a more careful evaluation and validation of the method to be used in clinical practice, the awareness of laboratory professionals should be raised as to the importance of evaluating the quality of biological samples before analysis and to adopt algorithms and approaches in the attempt to reduce problems related to erroneous results due to specific or non-specific interferences.

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.

Clinical presentation and diagnosis of Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD) is a heterogeneous group of pregnancy-related disorders characterized by abnormal proliferation of trophoblastic tissue. It encompasses the premalignant partial and complete hydatidiform mole but also the malignant invasive mole, choriocarcinoma, placental-site trophoblastic tumor, and epithelioid trophoblastic tumor. The clinical presentation changed to earlier detection after the introduction of first trimester ultrasounds. Patients are often asymptomatic, but vaginal bleeding continues to be the most common presenting symptom. Other symptoms can develop in the case of metastatic disease. Ultrasound, serum human chorionic gonadotrophin, and sometimes additional imaging such as CT, MRI, or PET can confirm the diagnosis and stage of disease. Familiarity with the pathogenesis, classification, imaging features, and treatment of GTD facilitates diagnosis and appropriate management.

Case report of persistent elevation of βhCG in a nonpregnant woman: A diagnostic puzzle

Detectable serum levels of beta subunit of human chorionic gonadotropin (βhCG) in nonpregnant, perimenopausal women bring confusion in both clinician and patient and could lead to unnecessary diagnostic and therapeutic procedures. A 45-year-old woman with the continuous elevation of βhCG underwent hysteroscopy, two laparoscopic surgeries, two explorative uterine cavity curettages and three cycles of cytostatic therapy. No ultrasonographic, macroscopic or histological signs of pregnancy, both uterine and ectopic or gestational trophoblastic disease were found. Both radiographic and computed tomography reports ruled out the presence of a nongynecological neoplasm. All recommended steps were taken for confirmation or ruling out the possibility of heterophile antibodies interference, but the results were not absolute. Finally, the referent laboratory confirmed the presence of the antibodies, but their exact type remains unknown. This case underlines the importance of the universally accepted protocol in the cases of persistent βhCG elevation in nonpregnant, perimenopausal women.