The effect of different human chorionic gonadotropin assay sensitivity on screening for ectopic pregnancy

Ruptured chronic ectopic pregnancy presenting with a negative urine pregnancy test

An acute ectopic pregnancy is one of the most common gynaecological emergencies in clinical practice. The diagnosis is usually established by a combination of clinical examination findings, correlated with sonographic and laboratory results. However, a chronic ectopic pregnancy (CEP) may occur when the ectopically implanted gestation, mostly in the fallopian tubes, invades the underlying structures, causing protracted destruction at the site of implantation. Individuals may present with subacute or chronic abdominal pain, abnormal vaginal bleeding, amenorrhoea and a low bHCG. The correct diagnosis is often only established following laparoscopy or even histologically after the operation. The authors present the case of a woman in her 30 s presenting with severe right sided abdominal pain and a failing pregnancy at 10 weeks gestation. Her urine pregnancy test was negative, but her serum bHCG was 18 IU/L. A transvaginal ultrasound scan confirmed a ruptured right tubal ectopic pregnancy. A laparoscopic salpingectomy was performed. This case provides an important reminder that a CEP should always be considered in the differential diagnosis of women of reproductive age presenting with acute lower abdominal pain, despite a negative urine pregnancy test.

The maternal plasma proteome changes as a function of gestational age in normal pregnancy: a longitudinal study

OBJECTIVE

Pregnancy is accompanied by dramatic physiological changes in maternal plasma proteins. Characterization of the maternal plasma proteome in normal pregnancy is an essential step for understanding changes to predict pregnancy outcome. The objective of this study was to describe maternal plasma proteins that change in abundance with advancing gestational age and determine biological processes that are perturbed in normal pregnancy.

STUDY DESIGN

A longitudinal study included 43 normal pregnancies that had a term delivery of an infant who was appropriate for gestational age without maternal or neonatal complications. For each pregnancy, 3 to 6 maternal plasma samples (median, 5) were profiled to measure the abundance of 1125 proteins using multiplex assays. Linear mixed-effects models with polynomial splines were used to model protein abundance as a function of gestational age, and the significance of the association was inferred via likelihood ratio tests. Proteins considered to be significantly changed were defined as having the following: (1) >1.5-fold change between 8 and 40 weeks of gestation; and (2) a false discovery rate-adjusted value of P < .1. Gene ontology enrichment analysis was used to identify biological processes overrepresented among the proteins that changed with advancing gestation.

RESULTS

The following results were found: (1) Ten percent (112 of 1125) of the profiled proteins changed in abundance as a function of gestational age; (2) of the 1125 proteins analyzed, glypican-3, sialic acid-binding immunoglobulin-type lectin-6, placental growth factor, C-C motif-28, carbonic anhydrase 6, prolactin, interleukin-1 receptor 4, dual-specificity mitogen-activated protein kinase 4, and pregnancy-associated plasma protein-A had more than a 5-fold change in abundance across gestation (these 9 proteins are known to be involved in a wide range of both physiological and pathological processes, such as growth regulation, embryogenesis, angiogenesis immunoregulation, inflammation etc); and (3) biological processes associated with protein changes in normal pregnancy included defense response, defense response to bacteria, proteolysis, and leukocyte migration (false discovery rate, 10%).

CONCLUSION

The plasma proteome of normal pregnancy demonstrates dramatic changes in both the magnitude of changes and the fraction of the proteins involved. Such information is important to understand the physiology of pregnancy and the development of biomarkers to differentiate normal vs abnormal pregnancy and determine the response to interventions.

A Ruptured Ectopic Pregnancy Presenting with a Negative Urine Pregnancy Test

A negative urine pregnancy test in the emergency department traditionally excludes the diagnosis of pregnancy. We report a rare case of ruptured ectopic pregnancy in a patient with a negative urine pregnancy test but with a serum beta-human chorionic gonadotropin (β-hCG) of 10 mIU/mL. The patient developed hemoperitoneum and required laparoscopy by Obstetrics and Gynecology (OB/Gyn). This case highlights the fallibility of the urine pregnancy test in diagnosing early pregnancy.

Chronic ectopic pregnancy--two cases of acute rupture despite negative beta hCG

We present the cases of two women with chronic ectopic pregnancies who presented with acute tubal rupture and hemoperitoneum despite negative beta-human chorionic gonadotropin (beta hCG) pregnancy tests. The appropriate screening use of beta hCG assays to ascertain pregnancy status, the mechanisms by which ectopic pregnancy may be seen with negative beta hCG tests, and the limitations of various assays are discussed. One patient, not initially believed to be pregnant, underwent computed tomography (CT) scan. Experience with use of CT scan in ectopic pregnancy diagnosis is limited; our case illustrates some of the possible CT scan findings. These cases illustrate the potential for ectopic pregnancy to rupture with low, if not undetectable beta hCG hormone levels, and consequently why it is not recommended to rely on quantitative beta hCG levels to guide the decision to proceed with ultrasound imaging.

Abdominal pain during pregnancy

In evaluating the pregnant patient with abdominal pain, the physician is presented with a wide range of diagnostic possibilities, including disorders that can occur in nonpregnant individuals and disorders that are unique to pregnancy. The development of modern laboratory testing methods and diagnostic imaging techniques has led to a decline in the morbidity and mortality from many of these disorders. With an understanding of the physiologic changes occurring during pregnancy, a careful history and physical examination, and judicious use of laboratory tests and imaging studies, the physician should be able to determine the cause of the patient's pain in the great majority of cases and, in the words of Babler, avoid "the mortality of delay."

Emergency department pregnancy testing

The rapid and accurate diagnosis of pregnancy is a necessity for emergency physicians. Physicians of the 1990s are fortunate to have available inexpensive, rapid pregnancy tests with virtually no false positives or negatives. The current basis of endocrine pregnancy tests is detection of Human Chorionic Gonadotrophin (HCG) in the serum or urine. The single HCG tests in combination with ultrasound, as well as serial HCGs, are also useful in the diagnosis of ectopic pregnancy. Serum progesterone, although at present not widely used in the emergency department, shows great promise as a test useful in the often difficult task of distinguishing ectopic and abnormal pregnancies from viable intrauterine pregnancies.

Ectopic pregnancy

Ectopic pregnancy remains a diagnostic and management challenge for nurse practitioners. The incidence and physiology of ectopic pregnancy, the current research on risk factors, detection methods, and management techniques, and counseling strategies are reviewed in this article. In addition, a protocol for nurse practitioners to improve the management and possibly lessen the serious impact of this challenging complication of pregnancy will be discussed.

Ectopic pregnancy in adolescents: a clinical review for pediatricians

Pediatricians caring for sexually active female adolescents and young adults need to be aware of the history, symptoms, and signs of an ectopic pregnancy. A thorough history and physical examination, including the pelvic examination, as well as specific diagnostic tests such as repeated quantitative hCG measurements, and ultrasonography when indicated, are crucial to proper and early diagnosis of a nonruptured ectopic pregnancy manageable by laparoscopy. The key to early diagnosis is to include ectopic pregnancy in the differential diagnosis in any sexually active female patient who has abnormal vaginal bleeding or abdominal pain. With early diagnosis, close observation, and appropriate management, the outcome is more likely to be favorable, with minimal morbidity and risk of death.

Ectopic pregnancy: ten common pitfalls in diagnosis

Ectopic pregnancy (EP) is a common, life-threatening complication of pregnancy. Modern technology (ultrasonography and improved pregnancy tests) should facilitate the diagnosis of EP. However, in a retrospective review of 65 cases of confirmed EP managed over 18 months at an urban teaching hospital, only 37 of 65 patients (57%, Cl95 = 44%, 69%) received prompt diagnosis and treatment; delays occurred in 28 patients (43%). In 10 of the 27 delayed cases, the diagnosis of EP was not even considered at the time of the first visit. In patients with a delayed diagnosis, morbidity (transfusions, cardiovascular instability, progression of illness) did occur. Diagnostic pitfalls that resulted in delayed care were reviewed, delays most commonly occurred in patients with a benign examination or "atypical" pain. Risk factors for EP were missed (7 patients, 25%), subtle clues to blood loss were often ignored (10 patients, 36%), and passage of tissue was thought to exclude EP (2 patients). Ultrasound was only helpful for half of the diagnoses and was misinterpreted in 27%. A dry or serous culdocentesis occurred frequently. In five patients, a falling or low quantitative human chorionic gonadotropin level was believed to indicate a completed abortion. The authors conclude that almost half of EPs are still missed on the first physician visit; errors and pitfalls in diagnosis are still common in the 1980s.

Pelvic pain: lessons from anatomy and physiology

Pelvic pain is often a difficult differential diagnosis in the emergency department. For physiologic reasons, pain in the pelvis is difficult to localize to a specific organ, and pelvic peritonitis is hard to recognize. On the other hand, differences in types of pain can be very useful in arriving at a correct diagnosis. The clinician must learn to recognize superficial and deep somatic pain, and differentiate between various types of visceral pain which originate from inflammation, ischemia, or colic. A review of the anatomy and physiology of pelvic pain helps identify some of the problems as well as potential aids in approaching the patient with pelvic pain.

Suspected ectopic pregnancy: ultrasound findings and hCG levels assessed by an immunofluorometric assay

One hundred suspected ectopic pregnancies were assessed by ultrasound on the basis of the following criteria: (A) viable intrauterine fetus, intrauterine pregnancy is certain; (B) intrauterine double sac or eccentric ring, intrauterine pregnancy is probable; (C) empty uterus or central ring but no adnexal mass or cul-de-sac fluid, ectopic pregnancy is possible; (D) empty uterus or central ring and an adnexal mass or cul-de-sac fluid, ectopic pregnancy is probable; (E) viable ectopic fetus, ectopic pregnancy is certain. Serum human chorionic gonadotrophin (S-hCG) was detected by an immunofluorometric assay (sensitivity 0.2 i.u./l, cut-off level 10 i.u./l). All the 51 patients in groups A and B had an intrauterine pregnancy. Normal gestational sacs were found also at S-hCG levels of less than 3600 i.u./l, the lowest level being 894 i.u./l. Ectopic pregnancy was confirmed in 29 of the 30 women in groups D and E. In the 19 women categorized into group C serial hCG assay and repeated sonography diagnosed ectopic pregnancy in 12 and miscarriage of an intrauterine pregnancy in the other seven. Ectopic pregnancy was always found when no gestational sac was seen by sonography and the hCG level was greater than 1000 i.u./l.

Analytical versus clinical sensitivity and specificity in pregnancy testing

A typical urine pregnancy test with the enzyme-linked immunoassay for human chorionic gonadotropin (Tandem Icon human chorionic gonadotropin) was performed as was a qualitative serum radioimmunoassay for human chorionic gonadotropin when the positive cutoff for the latter was set at 30 IU/L. There was 99.5% concordance between the two methods when performed on 871 simultaneous urine and serum specimens. Although the serum radioimmunoassay can detect levels of human chorionic gonadotropin as low as 10 IU/L, in this study the majority of patients with serum levels between 10 and 30 IU/L were not pregnant on clinical follow-up. Of nine patients with adequate clinical follow-up, a negative urine pregnancy test result, and a serum human chorionic gonadotropin level between 10 and 30 IU/L, only one proved to be pregnant. The Tandem Icon human chorionic gonadotropin urine test is sufficient for routine pregnancy testing and to rule out the need for immediate intervention in cases of ectopic pregnancy.

Emergency serum and urine HCG analyses with the 'Tandem ICON' procedure

A comparison between new urine and serum enzyme immunoassay techniques and existing serum radioimmunoassay techniques for the detection of HCG in the diagnosis of ectopic and early intrauterine pregnancy was undertaken. Urine HCG estimations by enzyme immunoassay were not found to be adequate for the exclusion of ectopic pregnancy due to a false negative rate of 12.5% (2 of 16 patients). Serum HCG estimations by enzyme immunoassay were found to compare favourably with radioimmunoassay techniques in the detection of HCG in both ectopic and early intrauterine pregnancy.