{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T18:49:25Z","timestamp":1780339765653,"version":"3.54.1"},"reference-count":49,"publisher":"Elsevier BV","issue":"13-14","license":[{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/legal\/tdmrep-license"}],"content-domain":{"domain":["elsevier.com","sciencedirect.com"],"crossmark-restriction":true},"short-container-title":["Clinical Biochemistry"],"published-print":{"date-parts":[[2013,9]]},"DOI":"10.1016\/j.clinbiochem.2013.06.019","type":"journal-article","created":{"date-parts":[[2013,7,3]],"date-time":"2013-07-03T23:11:36Z","timestamp":1372893096000},"page":"1257-1263","update-policy":"https:\/\/doi.org\/10.1016\/elsevier_cm_policy","source":"Crossref","is-referenced-by-count":7,"title":["Single point biochemical measurement algorithm for early diagnosis of ectopic pregnancy"],"prefix":"10.1016","volume":"46","author":[{"given":"Stephen A.","family":"Butler","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas K.A.","family":"Abban","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paola T.A.","family":"Borrelli","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jameel M.","family":"Luttoo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bryn","family":"Kemp","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ray K.","family":"Iles","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"78","reference":[{"issue":"4","key":"10.1016\/j.clinbiochem.2013.06.019_bb0005","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1007\/s00404-008-0731-3","article-title":"Tubal ectopic pregnancy: diagnosis and management","volume":"279","author":"Nama","year":"2009","journal-title":"Arch Gynecol Obstet"},{"issue":"4","key":"10.1016\/j.clinbiochem.2013.06.019_bb0010","first-page":"1080","article-title":"Ectopic pregnancy","volume":"61","author":"Tenore","year":"2000","journal-title":"Am Fam Physician"},{"issue":"9","key":"10.1016\/j.clinbiochem.2013.06.019_bb0015","first-page":"1707","article-title":"Diagnosis and management of ectopic pregnancy","volume":"72","author":"Lozeau","year":"2005","journal-title":"Am Fam Physician"},{"key":"10.1016\/j.clinbiochem.2013.06.019_bb0020","series-title":"The confidential enquiry into maternal and child health (CEMACH). Saving mothers' lives: reviewing maternal deaths to make motherhood safer \u2014 2003\u20132005. The seventh report on confidential enquiries into maternal deaths in the United Kingdom","first-page":"92","article-title":"Early pregnancy deaths","author":"Neilson","year":"2007"},{"issue":"7239","key":"10.1016\/j.clinbiochem.2013.06.019_bb0025","doi-asserted-by":"crossref","first-page":"916","DOI":"10.1136\/bmj.320.7239.916","article-title":"Ectopic pregnancy","volume":"320","author":"Tay","year":"2000","journal-title":"BMJ"},{"issue":"2","key":"10.1016\/j.clinbiochem.2013.06.019_bb0030","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1055\/s-2007-970047","article-title":"Ultrasound diagnosis of ectopic pregnancy","volume":"25","author":"Condous","year":"2007","journal-title":"Semin Reprod Med"},{"issue":"9485","key":"10.1016\/j.clinbiochem.2013.06.019_bb0035","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1016\/S0140-6736(05)67103-6","article-title":"Ectopic pregnancy","volume":"366","author":"Farquhar","year":"2005","journal-title":"Lancet"},{"issue":"10","key":"10.1016\/j.clinbiochem.2013.06.019_bb0040","first-page":"724","article-title":"Management of suspected ectopic pregnancy. impact of new diagnostic tools in 686 consecutive cases","volume":"41","author":"Ankum","year":"1996","journal-title":"J Reprod Med"},{"issue":"7271","key":"10.1016\/j.clinbiochem.2013.06.019_bb0045","doi-asserted-by":"crossref","first-page":"1235","DOI":"10.1136\/bmj.321.7271.1235","article-title":"Diagnosing suspected ectopic pregnancy. hcg monitoring and transvaginal ultrasound lead the way","volume":"321","author":"Ankum","year":"2000","journal-title":"BMJ"},{"issue":"3","key":"10.1016\/j.clinbiochem.2013.06.019_bb0050","first-page":"594","article-title":"Role of transvaginal ultrasonography in the diagnosis of ectopic pregnancy","volume":"70","author":"Mol","year":"1998","journal-title":"Fertil Steril"},{"issue":"6","key":"10.1016\/j.clinbiochem.2013.06.019_bb0055","doi-asserted-by":"crossref","first-page":"515","DOI":"10.1016\/0735-6757(90)90154-R","article-title":"Ectopic pregnancy: ten common pitfalls in diagnosis","volume":"8","author":"Abbott","year":"1990","journal-title":"Am J Emerg Med"},{"issue":"5","key":"10.1016\/j.clinbiochem.2013.06.019_bb0060","doi-asserted-by":"crossref","first-page":"1404","DOI":"10.1093\/humrep\/deh770","article-title":"The accuracy of transvaginal ultrasonography for the diagnosis of ectopic pregnancy prior to surgery","volume":"20","author":"Condous","year":"2005","journal-title":"Hum Reprod"},{"issue":"8","key":"10.1016\/j.clinbiochem.2013.06.019_bb0065","doi-asserted-by":"crossref","first-page":"1811","DOI":"10.1093\/humrep\/dep084","article-title":"The optimal timing of an ultrasound scan to assess the location and viability of an early pregnancy","volume":"24","author":"Bottomley","year":"2009","journal-title":"Hum Reprod"},{"issue":"5","key":"10.1016\/j.clinbiochem.2013.06.019_bb0070","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1002\/uog.10109","article-title":"Limitations of current definitions of miscarriage using mean gestational sac diameter and crown-rump length measurements: a multicenter observational study","volume":"38","author":"Abdallah","year":"2011","journal-title":"Ultrasound Obstet Gynecol"},{"key":"10.1016\/j.clinbiochem.2013.06.019_bb0075","series-title":"The management of tubal pregnancy. (guideline; no.21)","author":"Royal College of Obstetricians and Gynaecologists (RCOG)","year":"2004"},{"issue":"9","key":"10.1016\/j.clinbiochem.2013.06.019_bb0080","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1002\/jcu.20402","article-title":"Role of sonography in the diagnosis of ectopic pregnancy","volume":"35","author":"Gurel","year":"2007","journal-title":"J Clin Ultrasound"},{"issue":"6","key":"10.1016\/j.clinbiochem.2013.06.019_bb0085","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1097\/01.gco.0000191515.07019.cb","article-title":"Pregnancies of unknown location: diagnostic dilemmas and management","volume":"17","author":"Condous","year":"2005","journal-title":"Curr Opin Obstet Gynecol"},{"issue":"6","key":"10.1016\/j.clinbiochem.2013.06.019_bb0090","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1016\/S0196-0644(99)70094-6","article-title":"Rate of change of serial beta-human chorionic gonadotropin values as a predictor of ectopic pregnancy in patients with indeterminate transvaginal ultrasound findings","volume":"34","author":"Dart","year":"1999","journal-title":"Ann Emerg Med"},{"issue":"1","key":"10.1016\/j.clinbiochem.2013.06.019_bb0095","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/S0160-9963(00)80169-7","article-title":"Ectopic pregnancy: review and update","volume":"29","author":"Botash","year":"2000","journal-title":"Appl Radiol"},{"issue":"8","key":"10.1016\/j.clinbiochem.2013.06.019_bb0100","doi-asserted-by":"crossref","first-page":"1176","DOI":"10.1093\/oxfordjournals.humrep.a137817","article-title":"Analysis of serum human chorionic gonadotrophin levels in normal singleton, multiple and abnormal pregnancies","volume":"7","author":"Check","year":"1992","journal-title":"Hum Reprod"},{"issue":"5","key":"10.1016\/j.clinbiochem.2013.06.019_bb0105","doi-asserted-by":"crossref","first-page":"1239","DOI":"10.1016\/0002-9378(88)90263-3","article-title":"Serial human chorionic gonadotropin measurements in ectopic pregnancy","volume":"158","author":"Kadar","year":"1988","journal-title":"Am J Obstet Gynecol"},{"issue":"1","key":"10.1016\/j.clinbiochem.2013.06.019_bb0110","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1097\/01.AOG.0000128174.48843.12","article-title":"Symptomatic patients with an early viable intrauterine pregnancy: HCG curves redefined","volume":"104","author":"Barnhart","year":"2004","journal-title":"Obstet Gynecol"},{"issue":"3 Pt 1","key":"10.1016\/j.clinbiochem.2013.06.019_bb0115","first-page":"417","article-title":"Serial beta-hCG measurements in the early detection of ectopic pregnancy","volume":"75","author":"Shepherd","year":"1990","journal-title":"Obstet Gynecol"},{"issue":"1","key":"10.1016\/j.clinbiochem.2013.06.019_bb0120","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1530\/REP-09-0060","article-title":"Serum biomarkers of tubal ectopic pregnancy: current candidates and future possibilities","volume":"138","author":"Cartwright","year":"2009","journal-title":"Reproduction"},{"issue":"12","key":"10.1016\/j.clinbiochem.2013.06.019_bb0125","doi-asserted-by":"crossref","first-page":"2045","DOI":"10.1373\/clinchem.2003.022095","article-title":"Human chorionic gonadotropin isoforms in the diagnosis of ectopic pregnancy","volume":"49","author":"Borrelli","year":"2003","journal-title":"Clin Chem"},{"issue":"7","key":"10.1016\/j.clinbiochem.2013.06.019_bb0130","doi-asserted-by":"crossref","first-page":"682","DOI":"10.1016\/j.clinbiochem.2006.03.020","article-title":"A single serum test for measuring early pregnancy outcome with high predictive value","volume":"39","author":"Sutton-Riley","year":"2006","journal-title":"Clin Biochem"},{"issue":"11","key":"10.1016\/j.clinbiochem.2013.06.019_bb0135","doi-asserted-by":"crossref","first-page":"3163","DOI":"10.1093\/humrep\/dei218","article-title":"The value of a single combined measurement of VEGF, glycodelin, progesterone, PAPP-A, HPL and LIF for differentiating between ectopic and abnormal intrauterine pregnancy","volume":"20","author":"Daponte","year":"2005","journal-title":"Hum Reprod"},{"issue":"11","key":"10.1016\/j.clinbiochem.2013.06.019_bb0140","first-page":"1892","article-title":"Determining ectopic pregnancy risk using progesterone levels","volume":"73","author":"Scheid","year":"2006","journal-title":"Am Fam Physician"},{"issue":"4","key":"10.1016\/j.clinbiochem.2013.06.019_bb0145","doi-asserted-by":"crossref","first-page":"513","DOI":"10.1016\/S0015-0282(16)58560-4","article-title":"Single serum progesterone as a screen for ectopic pregnancy: exchanging specificity and sensitivity to obtain optimal test performance","volume":"66","author":"McCord","year":"1996","journal-title":"Fertil Steril"},{"issue":"11","key":"10.1016\/j.clinbiochem.2013.06.019_bb0150","doi-asserted-by":"crossref","first-page":"3220","DOI":"10.1093\/humrep\/13.11.3220","article-title":"The accuracy of single serum progesterone measurement in the diagnosis of ectopic pregnancy: a meta-analysis","volume":"13","author":"Mol","year":"1998","journal-title":"Hum Reprod"},{"issue":"7","key":"10.1016\/j.clinbiochem.2013.06.019_bb0155","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1053\/ajem.2002.35460","article-title":"Progesterone as a predictor of ectopic pregnancy when the ultrasound is indeterminate","volume":"20","author":"Dart","year":"2002","journal-title":"Am J Emerg Med"},{"issue":"4","key":"10.1016\/j.clinbiochem.2013.06.019_bb0160","doi-asserted-by":"crossref","first-page":"1106","DOI":"10.1016\/j.fertnstert.2003.08.049","article-title":"Novel placental and nonplacental serum markers in ectopic versus normal intrauterine pregnancy","volume":"81","author":"Mueller","year":"2004","journal-title":"Fertil Steril"},{"issue":"13","key":"10.1016\/j.clinbiochem.2013.06.019_bb0165","doi-asserted-by":"crossref","first-page":"5247","DOI":"10.1016\/S0021-9258(19)41303-3","article-title":"The amino acid sequence of human chorionic gonadotropin. the alpha subunit and beta subunit","volume":"250","author":"Morgan","year":"1975","journal-title":"J Biol Chem"},{"issue":"6480","key":"10.1016\/j.clinbiochem.2013.06.019_bb0170","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1038\/369455a0","article-title":"Crystal structure of human chorionic gonadotropin","volume":"369","author":"Lapthorn","year":"1994","journal-title":"Nature"},{"issue":"8","key":"10.1016\/j.clinbiochem.2013.06.019_bb0175","doi-asserted-by":"crossref","first-page":"647","DOI":"10.1016\/S0009-9120(03)00108-5","article-title":"Hyperglycosylated hCG (invasive trophoblast antigen, ITA) a key antigen for early pregnancy detection","volume":"36","author":"Cole","year":"2003","journal-title":"Clin Biochem"},{"key":"10.1016\/j.clinbiochem.2013.06.019_bb0180","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1186\/1477-7827-7-8","article-title":"New discoveries on the biology and detection of human chorionic gonadotropin","volume":"7","author":"Cole","year":"2009","journal-title":"Reprod Biol Endocrinol"},{"issue":"6","key":"10.1016\/j.clinbiochem.2013.06.019_bb0185","doi-asserted-by":"crossref","first-page":"769","DOI":"10.1093\/humupd\/dml029","article-title":"The classification, functions and clinical use of different isoforms of HCG","volume":"12","author":"Stenman","year":"2006","journal-title":"Hum Reprod Update"},{"key":"10.1016\/j.clinbiochem.2013.06.019_bb0190","doi-asserted-by":"crossref","first-page":"537","DOI":"10.1016\/j.anireprosci.2004.04.014","article-title":"Conceptus signals for establishment and maintenance of pregnancy","volume":"82\u201383","author":"Spencer","year":"2004","journal-title":"Anim Reprod Sci"},{"issue":"16","key":"10.1016\/j.clinbiochem.2013.06.019_bb0195","doi-asserted-by":"crossref","first-page":"1174","DOI":"10.1056\/NEJM199310143291608","article-title":"Ectopic pregnancy","volume":"329","author":"Carson","year":"1993","journal-title":"N Engl J Med"},{"issue":"2","key":"10.1016\/j.clinbiochem.2013.06.019_bb0200","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/S1472-6483(10)61745-2","article-title":"Decidualization of the human endometrial stromal cell: an enigmatic transformation","volume":"7","author":"Dunn","year":"2003","journal-title":"Reprod Biomed Online"},{"issue":"1\u20132","key":"10.1016\/j.clinbiochem.2013.06.019_bb0205","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/0028-2243(93)90131-U","article-title":"What do we know about the origin of CA 125?","volume":"49","author":"Bischof","year":"1993","journal-title":"Eur J Obstet Gynecol Reprod Biol"},{"issue":"2","key":"10.1016\/j.clinbiochem.2013.06.019_bb0210","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1016\/j.ejogrb.2005.10.014","article-title":"Receiver operator characteristics and diagnostic value of progesterone and CA-125 in the prediction of ectopic and abortive intrauterine gestations","volume":"125","author":"Katsikis","year":"2006","journal-title":"Eur J Obstet Gynecol Reprod Biol"},{"issue":"4","key":"10.1016\/j.clinbiochem.2013.06.019_bb0215","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1007\/BF02426356","article-title":"Maternal serum CA125 levels in early intrauterine and tubal pregnancies","volume":"252","author":"Kobayashi","year":"1993","journal-title":"Arch Gynecol Obstet"},{"issue":"12","key":"10.1016\/j.clinbiochem.2013.06.019_bb0220","first-page":"875","article-title":"Serum CA-125 levels in women with ectopic and intrauterine pregnancies","volume":"36","author":"Sadovsky","year":"1991","journal-title":"J Reprod Med"},{"issue":"2","key":"10.1016\/j.clinbiochem.2013.06.019_bb0225","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1016\/S0301-2115(00)00533-9","article-title":"Prognostic value of repeated serum CA 125 measurements in first trimester pregnancy","volume":"97","author":"Schmidt","year":"2001","journal-title":"Eur J Obstet Gynecol Reprod Biol"},{"issue":"6 Pt 1","key":"10.1016\/j.clinbiochem.2013.06.019_bb0230","doi-asserted-by":"crossref","first-page":"1729","DOI":"10.1016\/0002-9378(92)91563-P","article-title":"Receiver\u2013operator characteristic, efficiency analysis, and predictive value of serum progesterone concentration as a test for abnormal gestations","volume":"166","author":"Cowan","year":"1992","journal-title":"Am J Obstet Gynecol"},{"issue":"4","key":"10.1016\/j.clinbiochem.2013.06.019_bb0235","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1080\/01443610802149806","article-title":"The role of single serum progesterone measurement in conjunction with \u03b2hCG in the management of suspected ectopic pregnancy","volume":"28","author":"El Bishry","year":"2008","journal-title":"J Obstet Gynecol"},{"issue":"2","key":"10.1016\/j.clinbiochem.2013.06.019_bb0240","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1067\/mem.2000.108653","article-title":"Serum progesterone testing to predict ectopic pregnancy in symptomatic first-trimester patients","volume":"36","author":"Buckley","year":"2000","journal-title":"Ann Emerg Med"},{"issue":"2 Pt 1","key":"10.1016\/j.clinbiochem.2013.06.019_bb0245","doi-asserted-by":"crossref","first-page":"695","DOI":"10.1016\/0002-9378(95)90596-0","article-title":"Serum CA 125 levels and spontaneous abortion","volume":"172","author":"Hornstein","year":"1995","journal-title":"Am J Obstet Gynecol"}],"container-title":["Clinical Biochemistry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0009912013002968?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0009912013002968?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2025,9,14]],"date-time":"2025-09-14T15:40:50Z","timestamp":1757864450000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0009912013002968"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2013,9]]},"references-count":49,"journal-issue":{"issue":"13-14","published-print":{"date-parts":[[2013,9]]}},"alternative-id":["S0009912013002968"],"URL":"https:\/\/doi.org\/10.1016\/j.clinbiochem.2013.06.019","relation":{},"ISSN":["0009-9120"],"issn-type":[{"value":"0009-9120","type":"print"}],"subject":[],"published":{"date-parts":[[2013,9]]},"assertion":[{"value":"Elsevier","name":"publisher","label":"This article is maintained by"},{"value":"Single point biochemical measurement algorithm for early diagnosis of ectopic pregnancy","name":"articletitle","label":"Article Title"},{"value":"Clinical Biochemistry","name":"journaltitle","label":"Journal Title"},{"value":"https:\/\/doi.org\/10.1016\/j.clinbiochem.2013.06.019","name":"articlelink","label":"CrossRef DOI link to publisher maintained version"},{"value":"article","name":"content_type","label":"Content Type"},{"value":"Copyright \u00a9 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.","name":"copyright","label":"Copyright"}]}}