As Compared To Kaolin Clotting Time, Silica Clotting Time Is a Specific and Sensitive Automated Method For Detecting Lupus Anticoagulant

2001 ◽  
Vol 101 (2) ◽  
pp. 45-51 ◽  
Author(s):  
Francesco Dragoni ◽  
Clara Minotti ◽  
Giovanna Palumbo ◽  
Franco Faillace ◽  
Roberta Redi ◽  
...  
Keyword(s):  
Lupus Anticoagulant ◽  
Clotting Time ◽  
Automated Method ◽  
Kaolin Clotting Time

Scientific and Standardization Committee Communications Comparison of Test Methods for the Lupus Anticoagulant: International Survey on Lupus Anticoagulants-I (ISLA-1)

1990 ◽  
Vol 64 (03) ◽  
pp. 478-484 ◽  
Author(s):  
Thomas Exner ◽  
Douglas A Triplett ◽  
David A Taberner ◽  
Margaret A Howard ◽  
E Nigel Harris
Keyword(s):  
Lupus Anticoagulant ◽  
Test Methods ◽  
Positive Sample ◽  
Direct Proportion ◽  
Clotting Time ◽  
Preliminary Screening ◽  
Activated Platelets ◽  
Tissue Thromboplastin ◽  
Kaolin Clotting Time ◽  
Induced Defects

SummarySix lyophilized plasma samples were sent to 20 “expert” laboratories for assessment of lupus anticoagulant (LA). Four samples contained pooled LA of graded potency mixed with aged normal plasma. One contained LA plus cephalin phospholipid and one contained a nonspecific venom anticoagulant. Sixteen methods were used overall with some participants using up to 8 methods. Results were scored in regard to the known potencies of LA in the samples and other known induced defects.Activated partial thromboplastin time (APTT) tests used by most participants for preliminary screening were relatively sensitive, but non-specific. Platelet or phospholipid neutralization procedures (PNP) appeared to be sensitive and specific but showed a non-linear response to increased LA content. Kaolin clotting time (KCT) tests showed the most sensitive response to increased LA content but the weaker LA were not scored as abnormal by most laboratories as the samples may have contained platelet fragments. Other commonly used tests such as the tissue thromboplastin inhibition (TTI) test and the dilute Russell’s viper venom test (DRVVT) were carried out somewhat inconsistently. The variability in performance of tests in different laboratories indicates that standardization of methodology is urgently required.Generally it seemed that most clotting tests were “bypassed” by the addition of phospholipid to a known LA-positive sample in apparently direct proportion to their sensitivity. Sample preparation, especially prevention of contamination with activated platelets is a vital preliminary part in the assay of LA.

dRVVT Is more Sensitive than KCT or TTI for Detecting Lupus Anticoagulant Activity of Anti-β2-glycoprotein I Autoantibodies

1999 ◽  
Vol 81 (02) ◽  
pp. 256-258 ◽  
Author(s):  
A. Biasiolo ◽  
P. Rampazzo ◽  
T. Brocco ◽  
V. Pengo
Keyword(s):  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Test System ◽  
Clotting Time ◽  
Lupus Anticoagulants ◽  
Glycoprotein I ◽  
Tissue Thromboplastin ◽  
The Mean ◽  
Kaolin Clotting Time ◽  
Antibody Preparations

SummaryAnti-β2-glycoprotein I (β2-GPI) antibodies behave as classical Lupus Anticoagulants (LA), as they inhibit phospholipid-dependent coagulation reactions and their activity disappears in the presence of excess exogenous phospholipids (PLs). We have recently shown that a certain amount of PLs in the dilute Russell Viper Venom Time (dRVVT) test system is required to express LA activity of anti β2-GPI antibodies. We have now extended this observation to two other tests, i.e., Kaolin Clotting Time (KCT) in which PLs are not added, and Tissue Thromboplastin Inhibition test (TTI) in which PLs are extremely diluted. In fact, affinity-purified antibody preparations from 5 patients with antiphospholipid syndrome did not express or only weakly expressed anticoagulant activity in both tests; the mean ratios of coagulation times obtained with purified antibodies and that of control buffer were 1.11 and 1.0 for KCT and TTI, respectively. On the contrary, the mean ratios in dRVVT were 1.31 and 1.49 at a PLs dilution of 1:8 and 1:64, respectively. Therefore, the presence of LA activity due to autoantibodies to β2-GPI is characterized by a positive dRVVT and negative or only weakly positive KCT and TTI.

Prothrombin as cofactor for antiphospholipids

Lupus ◽  
1998 ◽  
Vol 7 (2_suppl) ◽  
pp. 37-40 ◽  
Author(s):  
M Galli ◽  
T Barbui
Keyword(s):  
Clinical Relevance ◽  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Low Risk ◽  
Immune Recognition ◽  
Clotting Time ◽  
Glycoprotein I ◽  
Russell’S Viper ◽  
Kaolin Clotting Time

Prothrombin is a common antigenic target of antiphospholipid antibodies, since anti-prothrombin antibodies are detected in about 50-90% of the patients. To allow proper immune recognition, prothrombin must be adsorbed on suitable anionic surfaces. The epitope(s) have not yet been identified: the majority of anti-prothrombin antibodies appear to be of poly- or oligoclonal nature. Anti-prothrombin antibodies, either alone or in combination with anti-β2-glycoprotein I antibodies, are responsible for the lupus anticoagulant activity of about 75% of the cases of phospholipid-dependent inhibitors of coagulation. The two antibodies may be discriminated by means of specific coagulation profiles generated by the comparison of the ratio of the Kaolin Clotting Time (KCT) and the dilute Russell's Viper Venom Time (dRVVT): the KCT profile, which mainly reflects the presence of anti-prothrombin antibodies and the dRVVT profile, which is mostly associated with anti-β2-glycoprotein I antibodies. This distinction, although somewhat artificial, may be clinically useful, since the KCT profile identifies patients at low risk to develop thrombosis. Similarly, most of the studies that measured anti-prothrombin antibodies by ELISA failed to find a significant association with thrombosis. In conclusion, the clinical relevance of these antibodies has not yet been established.

Heterogeneity of Lupus Anticoagulant (LA) Antibodies: LA Activity in Dilute Russell’s Viper Venom Time and Dilute Kaolin Clotting Time Detect Different Populations of Antibodies in Patients with the “Antiphospholipid” Syndrome

1998 ◽  
Vol 80 (08) ◽  
pp. 250-257 ◽  
Author(s):  
David Kandiah ◽  
Steven Krilis
Keyword(s):  
Lupus Anticoagulant ◽  
Protein C ◽  
Solid Phase ◽  
Clotting Time ◽  
Chromatographic Techniques ◽  
Differential Reactivity ◽  
Phospholipid Liposomes ◽  
Different Populations ◽  
Russell’S Viper ◽  
Kaolin Clotting Time

Summary“Antiphospholipid” (aPL) antibodies comprise two main groups of antibodies, lupus anticoagulant (LA) antibodies and “anticardiolipin” (aCL) antibodies which can be separated by certain chromatographic techniques. In this study we analysed the plasma of 10 patients with aPL antibodies, and were able to demonstrate that in four patients with both clotting test reactivities, the dilute Russell’s Viper Venom Time (dRVVT) activity can be separated from the dilute Kaolin Clotting Time (dKCT) reactivity by using a polyacrylamide-immobilised phosphatidylserine column but not with phospholipid liposomes. The differential reactivity of the autoantibodies in this patient population is not due to binding to β2GPI, prothrombin or protein C in solid-phase immunoassays. Hence LA antibodies detected in different phospholipid-dependent clotting tests detect different populations of antibodies in some APS patients and the routine detection of LA antibodies should be performed with at least two clotting tests looking at different coagulation reactions.

Detection of Lupus-Like Anticoagulants by an Enzyme-Linked Immunosorbent Assay Using a Partial Thromboplastin as Antigen; A Comparative Study

1990 ◽  
Vol 64 (01) ◽  
pp. 026-031 ◽  
Author(s):  
J Arnout ◽  
E Huybrechts ◽  
M Vanrusselt ◽  
C Falcon ◽  
J Vermylen
Keyword(s):  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Activated Partial Thromboplastin Time ◽  
The Other ◽  
Quantitative Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Clotting Time ◽  
Coagulation Tests ◽  
Tissue Thromboplastin ◽  
Kaolin Clotting Time

SummaryClotting assays allow qualitative rather than quantitative detection of the lupus anticoagulant. We have therefore studied the usefulness of an ELISA using a commercial partial thromboplastin, Thrombofax, oS antigen; the results obtained on 146 selected patient plasmas were compared to the results of coagulation tests (kaolin clotting time, tissue thromboplastin inhibition test, activated partial thromboplastin time) and of ELISAs using cardiolipin or phosphatidylserine as antigen. While satisfactory agreement was found within the group of coagulation tests or that of ELISAs, only a moderate agreement was obtained between clotting tests and ELISAs, the best being with the partial thromboplastin ELISA using low plasma dilutions. The study further indicates that ELISA techniques cannot entirely replace coagulation tests for the detection of a lupus anticoagulant, even when a partial thromboplastin is used as antigen. On the other hand, coagulation tests are less sensitive than ELISAs for the detection of antiphospholipid antibodies.

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