hCG Free Β-subunit Research Articles

What are the diagnostic considerations in a menopausal woman with a positive hCG test result?

EVIDENCE-BASED ANSWER The most common causes of elevated human chorionic gonadotropin (hCG) in a menopausal woman are a false-positive test (42%), quiescent gestational trophoblastic disease (GTD; 41%), low level pituitary production (10%), and malignancy (7.6%). After repeating the test in blood and urine, active malignancy and quiescent GTD should be ruled out by obtaining hyperglycosylated hCG and hCG free β-subunit. A physiologic pituitary source of hCG is likely in women with persistent low levels of hCG (<25–32 mIU/mL). This finding can be confirmed by the normalization of hCG levels after the administration of combined oral contraceptives for 2 or more weeks (SOR: C, case series of disease-oriented evidence).

Hyperglycosylated hCG drives malignancy in cancer cases.

Purpose: Trophoblastic cancers (Choriocarcinoma, testicular and ovarian germ cell malignancies) secrete hyperglycosylated hCG and non-trophoblastic cancers secrete hyperglycosylated hCG free β- subunit.Both are structural variants of hCG independent to the hormone hCG. They are autocrines acting on a transforming growth factor β-II (TGF-β-II), receptor not acting on the hormone receptor. Here these molecules were examined as drivers of malignancy. Methods: The cancer cell lines were examined, how they enzymatically invaded Matrigel chambers and how their growth responded to hyperglycosylated hCG and hyperglycosylated hCG free β-subunit signals. Use of hyperglycosylated hCG and hyperglycosylated hCG free β-subunit as tumor markers is examined in 959 cancer serum samples and 2257 cancer urine samples, plus 284 urines from benign disease patients. In addition, 56 new ovarian cancer urines were collected and tested in the supersensitive B204 assay. Results: Hyperglycosylated hCG and its free β-subunit are both strong promoters of malignancy functions. A total of 100% of trophoblastic malignancies produced hyperglycosylated hCG markers in serum and urine. A total of 30% of non-trophoblastic cancers were detected in serum and 44% in urine. As shown, in reality, considering simple and complex autocrine secretion, 100% of nontrophoblastic malignancies produce hyperglycosylated hCG and hyperglycosylated hCG free β- subunit markers in urine. As demonstrated, hyperglycosylated hCG and its free β-subunit exist in all human cancers and promote malignancy. Multiple other researchers have confirmed these results. Discussion: It is inferred that hyperglycosylated hCG and its free β-subunit are produced by all or most human cancers, and are the promoters of malignancy.

1. Persistent elevation of BHCG-levels in a patient with stage 5D Chronic Kidney Disease

Introduction and aim: A 24 year old female with Stage 5D chronic kidney disease (CKD) presents with persistent positive BHCG levels. BHCG elevation causes include pregnancy, pituitary production, hydatidiform mole, persistent trophoblast disease, malignancies and false positive hCG. Variants of the hCG molecule has been identified and includes sulfated hCG, hyperglycosylated hCG, hCG free β-subunit and hyperglycosylated hCG free β-subunit. Different hCG fractions are generated depending on the disease process. Isolated cases of falsely raised BHCG in both men and women with CKD have been reported. Origin of hCG has been attributed to pituitary production, coupled with CKD impairing metabolism and clearance of hCG.Methodology: Samples were tested by the NHLS Universitas Academic Laboratory using the Cobas e 601 analyzer (Roche) for intact human chorionic gonadotropin and the β-subunit. This immunoassay detects the holo-hormone, nicked forms of hCG, β-core fragment and free β-subunit. A qualitative urine test, detecting total hCG was negative, while a laboratory urine analysis had a positive result. Analysis on different instruments and serial dilutions excluded assay interference from human antimouse antibodies (HAMA), heterophilic antibodies or a high dose hook effect. Imaging studies including magnetic resonance imaging (MRI) brain, pelvis, computed tomography (CT) chest and pelvic ultra sound was performed. Diagnostic laparoscopy was refused by the patient due to her ongoing peritoneal dialysis.Results: Serial BHCG results show persistent elevation. Imaging studies yielded no explanation to HCG production.Conclusion: Elevated BHCG could be attributed to a tumour of gestational or non-gestational origin, failed pregnancy, familial elevated hCG, reduced clearance and degradation of hCG in CKD or changes of hCG associated with CKD. Immunoassay interference should be considered when patient results and clinical presentation differs. False positive test results may subject patients to unnecessary investigation and it may prevent patients from qualifying for organ transplantation.

Using a simulation model to assess risk of false negative point-of-care urinary human chorionic gonadotropin device results due to high-dose hook interference

BackgroundIt is unclear if the point-of-care (POC) Clinitest hCG device is subject to high-dose hook interference from physiological concentrations of intact human chorionic gonadotropin (hCG), β-core fragment of hCG (hCGβcf), and hCG free β-subunit (hCGβ) found in urine during pregnancy. We used a simulation model to address this question and related our findings to our institution's pregnant population in order to assess risk for potential false-negative hCG results. MethodsThe expected distribution of days relative to ovulation during routine POC hCG testing was estimated from 182 patients. Clinitest-Clinitek Status hCG device susceptibility to high-dose hook interference from hCG variants and potential risk of false-negative results as it relates to this population were evaluated by testing increasing concentrations of hCG, hCGβcf, hCGβ as well as urine simulating physiological hCG, hCGβcf and hCGβ concentrations expected during early pregnancy (≤44days post-ovulation). ResultsThe Clinitest-Clinitek Status hCG device exhibited high-dose hook interference from hCGβcf alone, but not from hCG, hCGβ, or simulated physiological urinary concentrations of combined hCG, hCGβcf and hCGβ expected during early pregnancy. The majority of our patient population had urinary hCG testing conducted during early pregnancy. ConclusionThe Clinitest-Clinitek Status hCG device is unlikely to exhibit false-negative urinary hCG results due to high-dose hook interference for women in early healthy pregnancy, although additional studies are necessary to determine potential risk in other patient populations. Visual interpretation of POC urinary hCG device results is an important failure mode to consider in risk analyses for erroneous urinary hCG device results.

The hCG Group: the Key Molecules in Human Evolution, Human Life, and Human Death

The term hCG refers to a group of molecules with common amino acid sequence, different glycosylation, and multimeric structure. These molecules include the pregnancy hormone hCG, made by placental syncytiotrophoblast cells, and the pregnancy autocrine hyperglycosylated hCG, made by placental cytotrophoblast cells, which drives placental growth during pregnancy and implantation of the placenta. Most human cancers make hyperglycosylated hCG free β-subunit. This drives cancer malignancy by following the invasive implantation pathway. Whereas hCG functions by acting on an hCG/LH joint receptor, hyperglycosylated hCG and hyperglycosylated hCG free β-subunit function by antagonizing a TGFβ receptor. CG and hyperglycosylated hCG first evolved with early simian primates. The early simian CG and hyperglycosylated CG were nonacidic rapidly clearing molecules. With their evolution evolved a primitive form of hemochorial placentation, primitive in that it was only minimally promoted by CG and hyperglycosylated CG. With the evolution of advanced simian primates came acidic variant of hCG and hyperglycosylated CG. The more acidic CG was longer circulating and more effectively promoted the establishment and growth of hemochorial placentation. With the evolution of humans came a very acidic variant of CG and hyperglycosylated CG. This was very much longer circulating and was an effective stimulant of hemochorial placentation. Early prosimian primates had a brain of 0.07 % of body mass, early simian primates had a brain mass of 0.17 %, advanced simian primates of 0.74 %, and humans of 2.4 %. Research indicates that brain mass grew with improving CG and hyperglycosylated CG activity and improving hemochorial placentation activity. The super CG variant produced by humans plays a key role in human pregnancy implantation and in failures of pregnancy, hypertense pregnancy, and invasion by gestational trophoblastic diseases. Research today shows that hyperglycosylated CG and hyperglycosylated CG free β-subunit drive most human trophoblastic and nontrophoblastic malignancies.

HCG structure: A logical perspective

The three dimensional crystal structure of hCG has been publish by Wu et al., Lapthorn et al., and Lustbader et al. The problem is that the crystal is missing 50% of the hCG molecular weight. It is missing the 4 N-linked and the 4 O-linked oligosaccharides and β-subunit amino acid residues 113–145. Here we add back in these missing structures, and considering 11 reported consequences we predict the final structure of hCG, hyperglycosylated hCG, nicked hCG and hCG free β-subunit. The consequences of 11 report are considered. The missing structures are examined by 2 webware programs, Bioinformatics Toolkit (Max Planck Institute), and Bioinformatics and Computational Biology (IIT Delhi). Structures are proposed for hCG, hyperglycosylated hCG, nicked hCG and hCG free β-subunit, considering the charge effect that the 12 or 19 sialic acid residues may have, movement of α-subunit loop 2 and movement of β-subunit safety belt.: Nicking causes a major structural change to β-subunit loop 2.

Are Laboratories Reporting Serum Quantitative hCG Results Correctly?

Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone that exists in multiple forms. Immunoassays commonly used in clinical laboratories measure intact hCG, total beta hCG (intact hCG + hCG free beta-subunit), and/or hCG free beta-subunit. Measurement of serum concentrations of hCG is useful for confirmation and monitoring of pregnancy, diagnosis of trophoblastic diseases and monitoring of the efficacy of treatment, and prenatal screening. Correctly reporting results for the various forms of hCG is clinically important. We prepared samples by addition of intact hCG and hCG free beta-subunit to an essentially hCG-free human serum matrix. The samples were analyzed by participant laboratories using various immunoassay methods. We identified errors in participant reporting of intact hCG results as total beta hCG (9.3%; 22 of 235 laboratories) and total beta hCG as intact hCG (13.1%; 8 of 61 laboratories). Many factors contribute to the erroneous reporting of hCG results, including (a) the complexity of hCG molecule and confusion of nomenclature on the various forms of hCG; (b) laboratory personnel's lack of awareness of the distinctions of the forms of hCG and failure to recognize the specificity of assays for their measurement; (c) lack of clarity and uniformity in manufacturers' reagent labeling; and (d) most product inserts' lack of information on the specificity of each method to the various forms of hCG.

Gestational trophoblastic diseases: 3. Human chorionic gonadotropin-free β-subunit, a reliable marker of placental site trophoblastic tumors

Objectives. Placental site trophoblastic tumor (PSTT) commonly presents with low and variable concentration of hCG immunoreactivity in serum which can be difficult to differentiate from early stage choriocarcinoma/gestational trophoblastic neoplasm (GTN) or quiescent gestational trophoblastic disease (quiescent GTD). Nontrophoblastic malignancies such as germ cell tumors or other tumors secreting low hCG must also be considered in the differential diagnosis. Because treatments for these conditions are different, a means of differentiating PSTT from other diagnoses is important. We investigate the usefulness of hCG-free β-subunit to make this discrimination. Methods. Data collected on cases referred to the USA hCG Reference Service for consultation served as a basis for this retrospective analysis. There were 13 cases with histology proven PSTT and 12 with nontrophoblastic malignancy. hCG-free β-subunit was measured by immunoassay and reported as a proportion of total hCG (hCG-free β-subunit(%)). hCG-free β-subunit(%) results were determined for all histologically proven cases of PSTT and for the nontrophoblastic malignancies. Comparisons of hCG-free β-subunit(%) were made and compared with those of the 82 choriocarcinoma/GTN cases and 69 quiescent GTD cases. The accuracy of hCG-free β-subunit(%) to discriminate these malignancies was analyzed by investigating the areas under receiver-operating characteristics curve ± standard error. Results. hCG-free β-subunit(%) was the predominant hCG form in cases of PSTT (mean ± standard deviation, 60 ± 19%) and nontrophoblastic malignancies (91 ± 11%), thus discriminating these diagnoses from choriocarcinoma/GTN (9.3 ± 9.2%) and from quiescent GTD (5.4 ± 7.8%). The cutoff of >35% free β-subunit is proposed. At this cutoff, 100% detection at 0% false-positive is achieved. The accuracy of hCG-free β-subunit(%) for this discrimination is 100 ± 0%. At a proposed cutoff of >80%, the free β-subunit test will also distinguish PSTT from nontrophoblastic malignancy, with 77% detection at 23% false-positive or an accuracy of 92 ± 3.2%. Conclusion. Measurement of the proportion hCG-free β-subunit(%) was found to be useful in the diagnosis of PSTT using proposed cutoff values of >35% and >80%. While this finding needs to be confirmed by larger studies, it would be reasonable to measure hCG-free β-subunit(%) whenever the diagnosis of PSTT is considered.

Human chorionic gonadotropin free β-subunit in the human seminal plasma: a new marker for spermatogenesis?

In the past 20 years, several factors were detected in the human seminal plasma and proposed as markers for spermatogenesis. Human chorionic gonadotropin (hCG) and its β-subunit were therefore investigated, and their seminal levels were found to be higher than those detected in the serum and to correlate with sperm parameters. Objective: We designed a retrospective study to determine the suitability of hCG free β-subunit concentration in the seminal plasma of fertile and infertile male patients as marker of spermatogenesis. Study design: A total of 79 infertile male patients were divided into four groups by their semen analysis results (group 1 [ n=8]: azoospermia; group 2 [ n=21]: severe oligozoospermia; group 3 [ n=40]: oligoasthenospermia (OAS); group 4 [ n=10]: asthenospermia) and 10 healthy volunteers of proven fertility were evaluated. Results: The hCG free β-subunit levels in the seminal plasma were found to be significantly higher ( P<0.0001) in the control group in respect to those assayed in the infertile patients and showed a correlation with sperm count ( r=0.5) and total motile sperm density ( r=0.5). Twenty-five patients were on treatment with oral Mesterolone (100 mg daily) plus Tamoxifen (20 mg daily) for 3–6 months. Apart from a significant improvement ( P<0.05) in sperm morphology, no significant changes in sperm count and motility were observed after the treatment in all the patients. In the seminal plasma of 10 patients who showed a significant increase in sperm count, hCG free β-subunit levels were found to be significantly higher compared to those detected in the remaining patients ( P<0.01). In all patients, these levels remained unchanged after the treatment. Conclusions: The evidence regarding the positive correlation between hCG free β-subunit levels in the seminal plasma and sperm concentration is consistent with the previous results regarding hCG levels. A previous study demonstrated that testosterone levels in seminal plasma correlated with sperm concentrations; from the same evidence regarding hCG we hypothesize that seminal plasma testosterone and hCG levels are correlated. Thus, hCG may play a paracrine role in the intratesticular regulation of testosterone secretion.

Hyperglycosylated Human Chorionic Gonadotropin (Invasive Trophoblast Antigen) Immunoassay: A New Basis for Gestational Down Syndrome Screening

Serum human chorionic gonadotropin (hCG) and hCG free beta-subunit tests are used in combination with unconjugated estriol and alpha-fetoprotein in the triple screen test, and with the addition of inhibin-A in the quadruple marker test for detecting Down syndrome in the second trimester of pregnancy. These tests have a limited detection rate for Down syndrome: approximately 40% for hCG or free beta-subunit alone, approximately 60% for the triple screen test, and approximately 70% for the quadruple marker test, all at 5%, or a relatively high, false-positive rate. New tests are needed with higher detection and lower false rates. Hyperglycosylated hCG (also known as invasive trophoblast antigen or ITA) is a new test. It specifically detects a unique oligosaccharide variant of hCG associated with Down syndrome pregnancies. We evaluated this new Down syndrome-directed test in prenatal diagnosis. Hyperglycosylated hCG was measured in urine samples from women undergoing amniocentesis for advanced maternal age concerns at 14-22 weeks of gestation, 1448 with normal karyotype and 39 with Down syndrome fetuses. The median hyperglycosylated hCG value was 9.5-fold higher in Down syndrome cases (9.5 multiples of the normal karyotype median). The single test detected 80% of Down syndrome cases at a 5% false-positive rate. Urine hyperglycosylated hCG was combined with urine beta-core fragment (urine breakdown product of serum hCG free beta-subunit), serum alpha-fetoprotein, and maternal age-related risk. This urine-serum combination detected 96% of Down syndrome cases at a 5% false-positive rate, 94% of cases at a 3% false-positive rate, and 71% of cases at a 1% false-positive rate. These detection rates exceed those of any previously reported combination of biochemical markers. Hyperglycosylated hCG is a new base marker for Down syndrome screening in the second trimester of pregnancy. The measurement of hyperglycosylated hCG can fundamentally improve the performance of Down syndrome screening protocols.

False-Positive hCG Assay Results Leading to Unnecessary Surgery and Chemotherapy and Needless Occurrences of Diabetes and Coma

Much concern has been raised by the unraveling at the hCG Reference Service of six cases of persistent phantom human chorionic gonadotropin (hCG). These are false-positive hCG results, which are likely attributable to human anti-mouse IgG or to heterophilic antibodies (1)(2)(3). The hCG Reference Service, started in January 1998 to aid with the interpretation of irregular or discordant hCG immunoassay results, requests parallel serum and urine samples. Each is tested in four separate two-step microtiter plate ELISAs (assay 1 detects intact hCG, assay 2 detects nonnicked or bioactive hCG only, assay 3 detects the hCG free β-subunit only, and assay 4 detects the hCG β-core fragment only) at three different concentrations (undiluted, a 1:2 dilution, and a 1:5 dilution). From the data, inferences are made about the nature (nonnicked or nicked hCG, free β-subunit, and β-core fragment) and likely source (trophoblast disease, pituitary hCG, cancer, or phantom hCG) of the hCG immunoreactivity. …

Screening for Down syndrome using urine hCG free β-subunit in the second trimester of pregnancy

Human chorionic gonadotropin (hCG) free beta-subunit levels were determined in 709 control and 13 Down syndrome urine samples from the second trimester of pregnancy. Results were normalized to urine creatinine concentration and converted to multiples of the unaffected pregnancy medium (MOM). The concentration of free beta-subunit in Down syndrome cases was 3.9 MOM. Seven of 13 Down syndrome pregnancies (54 per cent) had free beta-subunit levels at or above the 95th centile of unaffected pregnancies. Urine free beta-subunit may potentially be useful as a screening test for Down syndrome.

Stability of hCG free β-subunit and β-core fragment in urine

Stability of hCG free β-subunit and β-core fragment in urine