{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T02:47:22Z","timestamp":1777430842711,"version":"3.51.4"},"reference-count":14,"publisher":"SAGE Publications","issue":"6","license":[{"start":{"date-parts":[[1996,11,1]],"date-time":"1996-11-01T00:00:00Z","timestamp":846806400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Ann Clin Biochem"],"published-print":{"date-parts":[[1996,11]]},"abstract":"<jats:p>The stability of free \u03b2hCG (human chorionic gonadotrophin) was assessed using a dual \u03b1-fetoprotein and free \u03b2hCG assay. A significant increase in free \u03b2hCG concentration was observed in heparinized samples left unseparated for 24 h or more, the mean increase in 21 samples being 10.2% after 24 h ( P = &lt; 0.001), increasing to 45.7% after 96 h. Similar results were also obtained in clotted samples. The effect of the increase in free \u03b2hCG on the Down's risk estimate was calculated to assess the impact of delayed sample transport and separation. The Down's risk increased in all samples with increasing separation time, but this was most significant in two samples where, using a cut off of one in 250, the risk classification changed from low risk to high risk. These results suggest that delayed sample separation can have a significant effect on screening programmes using free \u03b2hCG, particularly with respect to those patients whose risk classification is changed.<\/jats:p>","DOI":"10.1177\/000456329603300606","type":"journal-article","created":{"date-parts":[[2014,2,5]],"date-time":"2014-02-05T16:58:39Z","timestamp":1391619519000},"page":"525-529","source":"Crossref","is-referenced-by-count":9,"title":["Down's Syndrome Screening Using Free \u03b2hCG: Instability Can Significantly Increase the Down's Risk Estimate"],"prefix":"10.1177","volume":"33","author":[{"given":"Janine M","family":"Beaman","sequence":"first","affiliation":[{"name":"Department of Clinical Chemistry, The Lewis Laboratories, Southmead Hospital, Bristol BS10 5NB, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Naheed","family":"Akhtar","sequence":"additional","affiliation":[{"name":"Department of Clinical Chemistry, The Lewis Laboratories, Southmead Hospital, Bristol BS10 5NB, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David J","family":"Goldie","sequence":"additional","affiliation":[{"name":"Department of Clinical Chemistry, The Lewis Laboratories, Southmead Hospital, Bristol BS10 5NB, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[1996,11,1]]},"reference":[{"key":"bibr1-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.297.6653.883"},{"key":"bibr2-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9378(90)90700-H"},{"key":"bibr3-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1093\/clinchem\/37.6.809"},{"key":"bibr4-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1177\/000456329202900504"},{"key":"bibr5-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1177\/000456329303000118"},{"key":"bibr6-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1093\/clinchem\/39.6.1064"},{"key":"bibr7-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1002\/pd.1970150808"},{"key":"bibr8-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1093\/clinchem\/39.10.2084"},{"key":"bibr9-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1177\/000456329002700506"},{"key":"bibr10-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1177\/000456329403100119"},{"key":"bibr11-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1002\/pd.1970140204"},{"key":"bibr12-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.307.6907.764"},{"key":"bibr13-000456329603300606","first-page":"41","volume":"1","author":"Spencer K","year":"1994","journal-title":"Proc UK NEQAS Meet"},{"key":"bibr14-000456329603300606","doi-asserted-by":"publisher","DOI":"10.1177\/096914139500200407"}],"container-title":["Annals of Clinical Biochemistry: International Journal of Laboratory Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/000456329603300606","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/000456329603300606","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T11:43:34Z","timestamp":1777376614000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/000456329603300606"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1996,11]]},"references-count":14,"journal-issue":{"issue":"6","published-print":{"date-parts":[[1996,11]]}},"alternative-id":["10.1177\/000456329603300606"],"URL":"https:\/\/doi.org\/10.1177\/000456329603300606","relation":{},"ISSN":["0004-5632","1758-1001"],"issn-type":[{"value":"0004-5632","type":"print"},{"value":"1758-1001","type":"electronic"}],"subject":[],"published":{"date-parts":[[1996,11]]}}}