Sarah A. Khanlian

Hyperglycosylated hCG (invasive trophoblast antigen, ITA) a key antigen for early pregnancy detection

OBJECTIVES Hyperglycosylated human chorionic gonadotrophin (hCG) is an hCG variant with extra-large O-linked oligosaccharides, produced by phenotypically invasive cytotrophoblast cells in choriocarcinoma and pregnancy. It is the principal form of hCG produced in the first weeks of gestation. We investigated the importance of hyperglycosylated hCG in pregnancy testing and its detection by current hCG tests. DESIGN AND METHODS We measured the concentration of hyperglycosylated hCG and total hCG in 512 pregnancies throughout gestation. We assessed and compared the abilities of 14 commonly used commercial laboratory hCG tests and 18 home pregnancy tests to detect regular and hyperglycosylated hCG. RESULTS Hyperglycosylated hCG is the principal source of hCG-related immunoreactivity in early pregnancy. In the week following missing menses, hyperglycosylated hCG measurements may be more sensitive than regular hCG measurements in detecting pregnancy. Of 14 commercial laboratory hCG tests, 3 appropriately detected hyperglycosylated hCG standard. Of 18 different home pregnancy products 11 poorly or very poorly detected this key antigen. CONCLUSIONS Hyperglycosylated hCG may be the key molecule in the detection of early pregnancy. However, the majority of tests poorly detected or failed to detect this key antigen. New pregnancy tests are needed that either solely detect hyperglycosylated hCG or equally detect regular hCG and hyperglycosylated hCG.

Hyperglycosylated hCG: A variant with separate biological functions to regular hCG

Hyperglycosylated hCG (hCG-H) is an over-glycosylated variant of hCG. While regular hCG is produced by differentiated syncytotrophoblast cells, hCG-H is independently secreted by stem cytotrophoblast cells. hCG-H has an independent function to regular hCG. It is the direct promoter of trophoblast invasion and malignancy. Invasion as in implantation of pregnancy and malignancy as in choriocarcinoma. Neither will occur in the absence of hCG-H. hCG-H measurements have multiple functions. Primarily or exclusively hCG-H is produced at the time of implantation of pregnancy and in the 2 weeks that follows. As such, a good pregnancy test should measure regular hCG and hCG-H equally. This is not commonly the case. Most tests poorly detect hCG-H. New pregnancy tests are needed, including those that measure only hCG-H. Considering that hCG-H is critical for implantation, hCG-H is also invaluable for determining pregnancy outcome and detecting failures. It makes a considerable more accurate test for detecting pregnancy failures and ectopic pregnancies than regular hCG. Down syndrome pregnancies are marked by poor trophoblast differentiation. As such, they are very well marked by using a combination of hCG-H measurements and other screening tests. hCG-H is also an absolute tumor marker for malignant or invasive gestational trophoblastic disease, it can discriminate active and inactive (quiescent) disease, and the need for chemotherapy.

Sensitivity of Over-the-Counter Pregnancy Tests: Comparison of Utility and Marketing Messages

OBJECTIVE To determine the sensitivity of seven over-the-counter pregnancy tests (OTC-PTs) using urine containing a mixture of human chorionic gonadotropin (hCG)-related molecules as found on the first day of missed menstrual period. DESIGN Blinded in vitro sensitivity analysis. SETTING Medical school laboratory. PARTICIPANTS None. INTERVENTIONS Urine was tested with OTC-PT devices at titers of 100, 50, 25, 12.5, 6.3, and 0 mIU/mL hCG immunoreactivity, and laboratory workers rated their confidence in the test result based on whether the test result was a clear, sharp, and unquestionable band in the test window. MAIN OUTCOME MEASURES Analytical sensitivity, defined as the urine concentration at which all OTC-PTs tested gave a positive result regardless of operator confidence score; clinical sensitivity of OTC-PTs, defined as the proportion of pregnancies likely to be detected on the first day of a missed period and calculated from the analytical sensitivity and a recently published regression curve for total urine hCG immunoreactivity in 25 urine samples from this period of gestation; percentage of tested devices showing a band in the test window at a specific hCG concentration measured devices positive; percentage faulty devices, defined as the proportion of tested devices failing to yield a band in the control window; and confidence score, determined from operator ratings for each device at each concentration of hCG. RESULTS First Response Early Result had an analytical sensitivity of 6.3 mIU/mL, which was estimated to detect greater than 95% of pregnancies on the day of missed period. The sensitivity of Clearblue Easy Earliest Results was 25 mIU/mL, which indicated detection of 80% of pregnancies. The sensitivity of the five other products was 100 mIU/mL or greater, indicating detection of 16% or less of pregnancies. Three of these last products included faulty devices. CONCLUSION Universal claims for OTC-PTs of more than 99% laboratory accuracy and use as early as the first day of missed period, while cleared for use by the U.S. Food and Drug Administration, are ambiguous and inappropriate for many products, according to these data. The majority of products tested were found to detect only a small percentage of pregnancies on the first day of a missed menstrual period. Until more data become available on the actual clinical sensitivity of these products, pharmacists should advise consumers to be cautious in interpreting test results.

The need for a quantitative urine hCG assay.

BACKGROUND The USA uniquely does not use quantitative urine human chorionic gonadotropin (hCG) tests despite being invaluable in pregnancy testing and in monitoring cancer patients. We look at current hCG tests and their detection of the degraded forms of hCG predominant in urine. We examine levels of urinary hCG, its usefulness in pregnancy testing, and advantages of urine testing in false positive hCG cases and cancer cases. METHODS hCG assays were blindly evaluated at 10 laboratories running different methodologies. Daily urine samples from 164 women were collected through 5 menstrual cycles or until pregnancy was achieved. Urines were assayed for total hCG. We also examined the use of quantitative urine hCG in confirming false positive serum hCG results in 80 clinical cases. RESULTS Only the Siemens Immulite test was shown to detect the degraded forms of hCG present in urine. This test equally recognized urine and serum hCG. We investigated background hCG in 9026 urines, the mean hCG level was 0.04 IU/L, and the 99th centile was 1.4 IU/L. In cycles where pregnancy was achieved, hCG could be detected in urine at 24.6 days of a 28.7 day menstrual cycle. At this time, the average hCG was 6.02 IU/L, setting a sensitivity level for quantitative urine hCG tests to detect pregnancy. Quantitative urinary hCG proved critical in detecting cancer in 3 of 80 cases complicated by false positive serum hCG. CONCLUSIONS The need for a quantitative urine hCG assay is undeniable and we invite manufacturers to produce a quantitative urine hCG test.

Detection of perimenopause or postmenopause human chorionic gonadotropin: an unnecessary source of alarm.

OBJECTIVE The normal pituitary production of human chorionic gonadotropin alongside luteinizing hormone, measurable in menopausal serum and urine was initially reported over 3 decades ago and has been described in numerous subsequent publications. Unfortunately, delays or cancellations of important medical procedures and use of needless chemotherapy still occurs because of the finding of human chorionic gonadotropin in perimenopausal and postmenopausal woman. We describe the problem and a concise approach to this management dilemma in menopausal women. STUDY DESIGN This is an outcomes study of 36 cases of perimenopausal and postmenopausal human chorionic gonadotropin evaluated in cases referred to the USA hCG Reference Service. RESULTS By report of the provided records, in 6 of 36 cases, unneeded chemotherapy was given for assumed recurrent gestational trophoblastic disease. In 9 cases, surgery was cancelled or postponed and in 3 cases renal transplantation was cancelled at the time of locating a matched donor kidney. In all cases the measured human chorionic gonadotropin was due to menopausal production of pituitary human chorionic gonadotropin. The average human chorionic gonadotropin detected in perimenopausal cases was 6.4 +/- 3.2 IU/L, and in postmenopausal cases was 11.6 +/- 7.0 IU/L or significantly higher. In 24 cases, therapeutic doses of high-estrogen birth control pill were used to confirm pituitary origin with 23 cases demonstrating successful human chorionic gonadotropin suppression. CONCLUSION Low levels of human chorionic gonadotropin production in the perimenopausal and postmenopausal state is a normal physiologic phenomenon. Provider education is warranted and management protocols are suggested in all health-related fields to clarify the normality of low level pituitary human chorionic gonadotropin production. Understanding this physiology will avoid delays in necessary therapies such as organ transplants, and will limit the misadventure of prescribing unnecessary treatments for presumed gestational malignancy.

Normal production of human chorionic gonadotropin in perimenopausal and menopausal women and after oophorectomy.

Background: The normal pituitary production of human chorionic gonadotropin (hCG) alongside luteinizing hormone, and its presence in women after bilateral oophorectomy, during perimenopause and menopause, as measured in serum and urine, has been known for 30 years and is described in numerous publications. Last year our group discussed this finding in a correspondence to the editor in the March 15th issue of New England Journal of Medicine, yet the misinterpretation of low-level hCG in these women seems to have increased in magnitude. Methods: This is an outcomes study of 36 cases of menopausal hCG referred to the USA hCG Reference Service over a 1-year period, from March 2007 to March 2008. Results: Eight cases occurred in women after oophorectomy, 28 were women in menopause/perimenopause. Surgery was postponed in 5 (14%) of 36 cases, and in 3 cases (8%), chemotherapy was unnecessarily administered. In 2 cases, computed tomography scans were cancelled. The average hCG detected was 10 ± 7.2 IU/L in cases receiving an oophorectomy and 9.8 ± 6.7 in perimenopause and 11 ± 6.2 IU/L in menopause cases. Conclusions: Low-level hCG production in woman in physiologic perimenopause, in menopause, or in women with prior bilateral oophorectomy is a normal biologic and biochemical phenomenon. Management protocols in all fields need to be changed to accept pituitary hCG as normal and recognize the clinical maneuvers that will secure the diagnosis. Understanding this physiology will avoid needless delays in necessary therapies such as organ transplant procedures and will limit the misadventure of prescribing unnecessary cancer treatments.