Dilute Russell 's viper venom time - Wikipedia Dilute Russell 's viper venom time This article needs attention from an expert in Medicine. The specific problem is : primary source - derived statements need to be supported as being clearly consensus via secondary sources, and consensus / current interpretation is in need of updating ; haematology expertise needed in particular ; it is unclear in which health systems the stated clinical values are considered normative ; citation median age is over a decade old ( range 8 - 20 yrs ), and 3 or 4 of 7 are primary / technical, rather than review / text book. WikiProject Medicine may be able to help recruit an expert. ( April 2016 ) hide This article has multiple issues. Please help improve it or discuss these issues on the talk page. ( Learn how and when to remove these template messages ) This article needs to be updated. Please update this article to reflect recent events or newly available information. ( April 2016 ) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( April 2016 ) This scientific article needs additional citations to secondary or tertiary sources such as review articles, monographs, or textbooks. Please add such references to provide context and establish the relevance of any primary research articles cited. Unsourced material may be challenged and removed. ( April 2016 ) Russell 's viper, Daboia russelii Dilute Russell 's viper venom time ( dRVVT ) is a laboratory test often used for detection of lupus anticoagulant ( LA ). Mechanism This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( April 2016 ) This in vitro diagnostic test is based on the ability of the venom of the Russell 's viper to induce thrombosis. The venom contains some substances ( RVV - V and RVV - X ) which directly activate factor V and factor X, which turns prothrombin into thrombin in the presence of phospholipid and calcium. In the dRVVT assay, low, rate - limiting concentrations of both Russell 's viper venom and phospholipid are used to give a standard clotting time of 23 to 27 seconds. This makes the test sensitive to the presence of lupus anticoagulants, because these antibodies interfere with the clot - promoting role of phospholipid in vitro, and their presence results in a prolonged clotting time. A mixing study is then performed, which consists of adding an equal volume of the patient 's plasma to normal plasma ; in this study, one would expect the clotting time to return to the normal range if there was only a deficiency of coagulation factors alone. A prolonged clotting time of 30 seconds or greater that does not correct despite the mixing study suggests the presence of a lupus anticoagulant. An abnormal result for the initial dRVVT assay should be followed by a dRVVT confirmatory test. In this test, the inhibitory effect of lupus anticoagulants on phospholipids in the dRVVT can be overcome by adding an excess of phospholipid to the assay. The clotting times of both the initial dRVVT assay and confirmatory test are normalized and then used to determine a ratio of time without phospholipid excess to time with phospholipid excess. In general, a ratio of greater than 1.3 is considered a positive result and implies that the patient may have antiphospholipid antibodies. The dRVVT test has a higher specificity than the aPTT test for the detection of lupus anticoagulant, because it is not influenced by deficiencies or inhibitors of clotting factors VIII, IX or XI as the venom only activates factors V and X. Variations in the test can affect the results. Use in diagnosis The dRVVT is one component of a workup of a suspected antiphospholipid antibody, the other component being the serological testing for anticardiolipin antibodies and anti-β2 glycoprotein - I antibodies using ELISA technology. The Sapporo criteria require at least one of the above laboratory tests to be positive and the patient to have at least one clinical manifestation of antiphospholipid syndrome, such as vascular thrombosis or fetal mortality / morbidity, in order to diagnose the antiphospholipid syndrome. Positive laboratory test results should be seen on two separate occasions at least six weeks apart in order for diagnosis. Antiphospholipid antibody syndrome is an important marker for recurrent thrombosis, and often warrants indefinite anticoagulant ( blood thinner ) therapy. The criteria were defined in 1999, and revised in 2006. References Jump up ^ Moore GW, Tugnait S, Savidge GF ( 2005 ). `` A new - generation dilute Russell 's viper venom time assay system for lupus anticoagulants : evaluation of detection utilising frozen reagents and controls ''. Br. J. Biomed. Sci. 62 ( 3 ) : 127 -- 32. PMID 16196459. Jump up ^ Triplett DA ( September 2000 ). `` Use of the dilute Russell viper venom time ( dRVVT ) : its importance and pitfalls ''. J. Autoimmun. 15 ( 2 ) : 173 -- 8. doi : 10.1006 / jaut. 2000.0414. PMID 10968905. ^ Jump up to : `` Snake venoms and the hemostatic system ''. Toxicon. 36 ( 12 ) : 1749 -- 1800. December 1998. doi : 10.1016 / S0041 - 0101 ( 98 ) 00126 - 3. ^ Jump up to : Kini, R. Manjunatha ( 2006 - 08 - 01 ). `` Anticoagulant proteins from snake venoms : structure, function and mechanism ''. Biochemical Journal. 397 ( Pt 3 ) : 377 -- 387. doi : 10.1042 / BJ20060302. ISSN 0264 - 6021. PMC 1533313. PMID 16831131. ^ Jump up to : Thiagarajan P, Pengo V, Shapiro SS ( 1986 ). `` The use of the dilute Russell viper venom time for the diagnosis of lupus anticoagulants ''. Blood. 68 ( 4 ) : 869 -- 74. PMID 3092888. Jump up ^ Hoppensteadt, DA ; Fabbrini, N ; - 1 # Bick, RL. ; Messmore, HL ; Adiguzel, C ; Fareed, J ; et al. ( 2008 ). `` Laboratory Evaluation of the Antiphospholipid Syndrome ''. Hematol Oncol Clin North Am. 22 ( 1 ) : 19 -- 32. doi : 10.1016 / j. hoc. 2007.10. 009. PMID 18207063. Jump up ^ Swadzba, J ; Iwaniec, T ; Pulka, M ; De Laat, B ; De Groot, PG ; Musial, J ( September 2011 ). `` Lupus anticoagulant : performance of the tests as recommended by the latest ISTH guidelines ''. Journal of thrombosis and haemostasis : JTH. 9 ( 9 ) : 1776 -- 83. doi : 10.1111 / j. 1538 - 7836.2011. 04420. x. PMID 21707912. Jump up ^ Moore GW, Savidge GF ( April 2004 ). `` Heterogeneity of Russell 's viper venom affects the sensitivity of the dilute Russell 's viper venom time to lupus anticoagulants ''. Blood Coagul. Fibrinolysis. 15 ( 3 ) : 279 -- 82. doi : 10.1097 / 00001721 - 200404000 - 00015. PMID 15060428. Jump up ^ Miyakis, S ; Lockshin, MD ; - 1 # Atsumi, T. ; Branch, DW ; Brey, RL ; Cervera, R ; Derksen, RH ; De Groot, PG ; et al. ( 2006 ). `` International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome ( APS ) ''. Journal of Thrombosis and Haemostasis. 4 ( 2 ) : 295 -- 306. doi : 10.1111 / j. 1538 - 7836.2006. 01753. x. PMID 16420554. Jump up ^ Kaul M, Erkan D, Sammaritano L, Lockshin MD ( July 2007 ). `` Assessment of the 2006 revised antiphospholipid syndrome classification criteria ''. Ann. Rheum. Dis. 66 ( 7 ) : 927 -- 30. doi : 10.1136 / ard. 2006.067314. PMC 2497429. PMID 17337473. `` The template below ( Myeloid blood tests ) is being considered for merging. See templates for discussion to help reach a consensus. '' hide Myeloid blood tests ( CPT 85002 -- 85999 ) Clotting CBC Platelet count Mean platelet volume vWF : Ristocetin - induced platelet aggregation clotting factors : Prothrombin time Partial thromboplastin time Thrombin time Activated clotting time other / general : coagulation Bleeding time animal enzyme Reptilase time Ecarin clotting time Dilute Russell 's viper venom time Thromboelastography Thrombodynamics test fibrinolysis : Euglobulin lysis time D - dimer Red blood cell indices CBC RBC count Hematocrit Hemoglobin ratios : Mean corpuscular hemoglobin Mean corpuscular hemoglobin concentration Mean corpuscular volume Red blood cell distribution width Fetal hemoglobin : Apt -- Downey test Kleihauer -- Betke test Other Reticulocyte index Haptoglobin Mentzer index CFU - GM Nitro blue tetrazolium chloride test Complete blood count Absolute neutrophil count Other Blood film Blood viscosity Erythrocyte sedimentation rate Retrieved from `` https://en.wikipedia.org/w/index.php?title=Dilute_Russell%27s_viper_venom_time&oldid=797714293 '' Categories : Blood tests Hidden categories : All pages needing factual verification Wikipedia articles needing factual verification from April 2016 Articles needing expert attention from April 2016 All articles needing expert attention Medicine articles needing expert attention Wikipedia articles in need of updating from April 2016 All Wikipedia articles in need of updating Articles needing additional references from April 2016 All articles needing additional references Articles lacking reliable references from April 2016 All articles lacking reliable references Articles with multiple maintenance issues All articles with unsourced statements Articles with unsourced statements from April 2016 Talk About Wikipedia Español Edit links This page was last edited on 28 August 2017, at 19 : 30 ( UTC ). 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Question: dilute russell’s viper venom test (drvvt) which coagulation factor is activated by the venom
Answer: factor V