Test Details
Methodology
Clot-based assays for lupus anticoagulants and enzyme-linked immunoassays (ELISAs) for antiphospholipid antibodies
Result Turnaround Time
4 - 6 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
This test includes LA-sensitive activated partial thromboplastin time (PTT-LA); dilute Russell viper venom time (dRVVT); dilute prothrombin time (dPT); dPT confirm ratio; and thrombin time, fibrinogen. If PTT-LA, dRVVT or thrombin time are extended, reflex testing is performed and additional charges/CPT code(s) will apply. Profile also includes anticardiolipin antibodies (ACA), IgA, IgG, IgM; B2-Glycoprotein 1 Antibodies, IgA, IgG, IgM; and antiphosphatidylserine, IgG and IgM.
Use
This test is used for qualitative detection of lupus anticoagulants (LA) in plasma and semiquantitative detection of antiphospholipid antibodies in serum.
Limitations
Important note: Results are consistent with the presence of a lupus anticoagulant. As only persistent lupus anticoagulant (LA) positivity meets laboratory diagnostic criteria for antiphospholipid syndrome, repeat testing in 12 or more weeks is recommended, ideally in the absence of anticoagulant therapy.4 Patients with high clinical suspicion of having APS, but without presence of criteria aPL, are suggested to have “seronegative APS” (SNAPS). These patients may be positive for so-called noncriteria antiphospholipid antibodies (aPL) or be negative for the criteria aPL through insufficient sensitivity of the assays.31,32
Inherent to the test principle of phospholipid-based coagulation assays, LAC testing is prone to interferences.
• Elevated c-reactive protein interferes in vitro with aPTT testing through its affinity for phospholipids, leading to false-positive results of the LAC test.33
• Increased factor VIII (FVIII) coagulant activity is associated with shorter aPTT clotting
times and can lead to false-negative LAC aPTT screening assays.34 dRVVT screening is not influenced by FVIII levels as factor X is directly activated by Russell’s viper venom.
• Increased levels of FVIII can be observed during pregnancy, surgery, inflammation, malignancy and other conditions.35
• LAC is often found to be positive during inflammatory conditions, without clear association with a clinical APS phenotype, recently highlighted in patients with COVID-19.36 LA positivity after viral and bacterial infections is often transient and not accompanied by the clinical APS phenotype.36
• Certain drugs (e.g., antibiotics, antiarrhythmics, and chlorpromazine) and to a lesser extent vaccines (e.g., against hepatitis B virus) are also found to be associated with LA activity.37
• In the acute setting of thrombosis, increased FVIII levels can lead to false-negative LA assessment, while increased CRP can lead to false-positive LA testing. Therefore, it is not recommended to assess LAC status during the thrombotic event or in patients with acute inflammation. Retesting patients with LAC positivity at least 12 weeks after the initial finding is an important strategy in avoiding misclassification of patients with transient LAC.4
• Anticoagulation treatment complicates LAC testing and interpretation by prolonging aPTT and dRVVT. LAC testing during anticoagulation treatment is discouraged,4 although it is not always desirable to postpone LAC analysis until treatment cessation.21
• Vitamin K antagonists (i.e., warfarin) can cause prolongation of aPTT and dRVVT through production of incomplete coagulation factors by inhibition of vitamin K-dependent gamma carboxylation of factors II (prothrombin), VII, IX, and X.38 This acquired factor deficiency can lead to false-positive interpretation of LA testing, especially in the screening step, and false negative in the mixing step.
Unfractionated heparin (UFH), LMWH and heparinoids mainly interfere by indirectly inhibiting thrombin and activated factor X (FXa) action.39 dRVVT and the PTT-LA reagents contain heparin-neutralizing agents, quenching the effect of heparin in vitro.
While pretreatment with activated charcoal can ameliorate the effects of a Direct Oral Anticoagulant (DOAC) on lupus anticoagulant testing, there is a possibility that residual drug from samples with high or super-therapeutic levels of drug could interfere with the testing.
DOACs directly inhibit thrombin (e.g., dabigatran) or FXa (e.g., apixaban, betrixaban, edoxaban, and rivaroxaban) (40), with various effects on coagulation tests, even at trough levels, leading to both false-negative and false-positive LA interpretation.41-44
Custom Additional Information
Antiphospholipid syndrome (APS) represents a serious clinical condition in which patients may be at high risk for thrombosis, pregnancy/fetal morbidity/mortality, or other multisystem clinical presentations.1 The latest APS classification criteria2 identify patients as having definite APS based on a clinical and laboratory scoring system as the entry criterion and persistent presence of certain antiphospholipid antibodies (aPL). These aPL tests are also more broadly used to diagnose or exclude APS.3
Antiphospholipid syndrome (APS) is an acquired autoimmune disorder that manifests clinically as recurrent venous, arterial and/or small vessel thrombosis and/or fetal loss in the context of persistently positive antiphospholipid antibodies (aPL).4-10 At least one clinical criterion and one laboratory criterion must be present for a patient to be classified as having APS. The clinical criteria consist of vascular thrombosis and pregnancy morbidity.
Vascular thrombosis is defined as the following:
• One or more clinical episodes of arterial, venous, or small-vessel thrombosis in any tissue or organ confirmed by findings from imaging studies, Doppler studies or histopathology
• Thrombosis may involve the cerebral vascular system, coronary arteries, pulmonary system (emboli or thromboses), arterial or venous system in the extremities, hepatic veins, renal veins, ocular arteries or veins or adrenal glands
Investigation is warranted if a history of deep venous thrombosis, pulmonary embolism, acute ischemia, myocardial infarction (MI), or stroke (especially when recurrent) is present in a younger individual (males <55 years; females <65 years) or in the absence of other risk factors.
Pregnancy morbidity is defined as the following:
• One or more late-term (>10 weeks' gestation) spontaneous abortions
• One or more premature births of a morphologically healthy neonate at or before 34 weeks’ gestation because of severe preeclampsia or eclampsia or severe placental insufficiency
• Three or more unexplained, consecutive, spontaneous abortions before 10 weeks’ gestation
Besides the criteria currently regarded as classification criteria for APS, other manifestations such as thrombocytopenia, autoimmune hemolytic anemia, livedo reticularis, neurologic manifestations, nephropathy and valvular heart disease are associated with presence of aPL.11-14
In addition to the clinical criteria, at least one of the following laboratory criteria is necessary for the classification of APS4-8:
• Presence of lupus anticoagulant (LA) in plasma on two or more occasions at least 12 weeks apart
• Presence of moderate to high levels of anticardiolipin (aCL; IgG or IgM) in serum on two or more occasions at least 12 weeks apart5
• Presence of moderate to high levels of anti-beta-2 glycoprotein I antibodies (β2GP1; IgG or IgM) in serum on two or more occasions at least 12 weeks apart5
Lupus Anticoagulant Testing
Current LA testing guidelines recommend use of at least two tests based on different assay principles before excluding LA, recommending the activated partial thromboplastin time (aPTT) and dilute Russell viper venom time (dRVVT).4,6,15 The aPTT is based on contact activation, and the dRVVT is based on factor (F)X activation.16,17
Lupus anticoagulants (LA) are nonspecific autoantibodies that extend the clotting time of phospholipid-dependent clotting assays.4-8 LA do not specifically inhibit individual coagulation factors; rather they neutralize anionic phospholipid-protein complexes that are involved in the coagulation process. The International Society of Thrombosis and Haemostasis (ISTH) has established criteria for the identification of LA by clot-based asays.4 Prolongation of clot-based assays is dependent on the sensitivity of the reagent employed to detect the presence of LA. Assays are made more sensitive for LA by decreasing the amount of phospholipid in the reagent. The ISTH guidelines call for the use of two LA-sensitive reagent systems in testing for LA as no single test has sufficient sensitivity and specificity.4-8 Both assays are complementary as aPL do not always react in both test systems.18
The most recent update of the ISTH guidelines on LA detection recommends parallel testing of the dilute Russell’s viper venom time (dRVVT) and aPTT.4 The dilute Russell Viper Venom Time (dRVVT) dilute and activated Partial Thromboplastin Time (aPTT-LA) are the most used tests for LA and are specifically mentioned in the guidelines.4 The dRVVT assay is based on direct activation of factor X by an enzyme present in the venom of Russell’s vipers. aPL in patient plasma will react with phospholipid components of the reagent through cofactors and prolong the dRVVT by decreased activity of the prothrombin activator complex.19
The aPTT-LA assay is based on activation of the contact (intrinsic) pathway. Analogous to the dRVVT assay, aPL inhibits phospholipid-dependent steps in the aPTT coagulation pathway. A prolonged clotting time in either screening test is followed by demonstration of phospholipid dependence and inhibitory properties in confirmatory and mixing tests, respectively, which are modifications of the parent screening test. In order for an extended screening result to be interpreted as a lupus anticoagulant, the assay clotting time must exhibit correction (reduced clotting time) on readdition of phospholipid in what is referred to as a “confirmation” assay.
The Labcorp LA reflex testing procedure was designed based on the recommendations of the Scientific and Standardization Committee for lupus anticoagulant/antiphospholipid antibodies of the ISTH updated in 2020.4 The three-step procedure starts with performance of the two LA-sensitive screening tests (PTT-LA and dRVVT). Samples with prolonged screening results for either of these tests are further tested by a mixing test (to exclude a deficiency in coagulation factor as the cause of the extended screening test) and a confirmation test (to ascertain if a phospholipid dependent inhibitor (LA) is detected). The LAC testing is considered positive if one of the two test systems gives a positive confirmation result.4
Ancillary Coagulation Tests
Because LA are detected based on their effect on clotting assays, the presence of anticoagulants in the patient sample can confound the results of this testing. Several ancillary coagulation tests are performed for samples with extended LA screening results to garner information on potential confounders that can impact the accuracy of LA testing.
• Fibrinogen Activity: Transient inflammation (i.e., acute phase reaction) that can cause an elevation of FVIII levels, shortening PTT-LA clot times and causing LA to be missed.20,21 Also, elevations in c-reactive protein levels associated with inflammation can prolong phospholipid-dependent clotting tests.22 Consistent with ISTH guidelines for LA testing, a fibrinogen activity level is measured as part of the LA panel in order to identify cases where potential interference could potentially confound the interpretation of results.
• Dilute Prothrombin Time (dPT): Vitamin K antagonists (VKAs) may cause false-positive or false-negative results.23 A markedly elevated dPT suggest that the patient is treated with a VKA, and the results of testing might be compromised.4 The dPT assay, combined with the dPT confirm ratio also screens for the phospholipid-dependent inhibitors of a different part of the coagulation cascade than the PTT-LA and dRVVT tests.24
• Thrombin Time: The thrombin time is extended in samples from patients treated with unfractionated or low molecular weight heparin. These drugs extend the PTT-LA (and sometimes the dRVVT) screening results from treated patients.25 A thrombin time is performed as a reflex for all samples with an extended PTT-LA result. If the thrombin time is greater than 30 seconds, a Thrombin Time Mix with normal plasma is performed.
Correction on mix indicates that the thrombin time elevation was due to a factor deficiency. If the thrombin time fails to correct on mix, a heparin neutralizer is added to the sample and the thrombin time repeated. The result of this testing is referred to as the Thrombin Time, Neutralized. A correction of the thrombin time into the normal range after sample treatment with heparin neutralizer indicates that the patient was treated with heparin prior to sample collection. The dRVVT and PTT-LA reagents employed by Labcorp contain heparin neutralizers meant to minimize the effects of these anticoagulants.
Nonetheless, the results of LA testing performed on heparin treated patients should be interpreted with caution. An extended thrombin time that fails to correct on mix with normal plasma or after heparin neutralization suggest that a non-heparin inhibitor is present in the sample. Therapeutic treatment with the thrombin inhibitor (i.e., dabigatran, a direct oral anticoagulant) can produce this pattern of results.
Specimen Requirements
Specimen
Sodium citrate plasma, frozen, and serum, refrigerated
Volume
2.6 mL frozen plasma and 2 mL serum
Container
Blue-top (sodium citrate) tube and gel-barrier or red-top tube
Collection Instructions
Plasma: Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.26 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.27,28 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anti-coagulant with the blood. A discard tube is not required prior to collection of coagulation samples except when using a winged blood collection device (i.e., "butterfly"), in which case a discard tube should be used.29,30
When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge for 10 minutes and carefully remove 2/3 of the plasma using a plastic transfer pipette, being careful not to disturb the cells. Deliver to a plastic transport tube, cap and recentifuge for 10 minutes.
Use a second plastic pipette to remove plasma, staying clear of the platelets at the bottom of the tube. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
It is important to centrifuge blood samples for plasma collection immediately after collection to separate the plasma from the blood cells. If immediate centrifugation is not possible, collected blood specimens should be kept on ice and centrifuged within an hour.
Serum: If a red-top tube is used, transfer separate serum to a plastic transport tube. Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Stability Requirements
See individual tests.
Storage Instructions
Freeze plasma; refrigerate serum.
Patient Preparation
Do not draw from an arm with a heparin lock or heparinized catheter.
Causes for Rejection
Gross hemolysis; clotted specimen; frozen specimen thawed in transit; improper labeling
Footnotes
1. Knight JS, Branch DW, Ortel TL. Antiphospholipid syndrome: advances in diagnosis, pathogenesis, and management. BMJ. 2023 Feb 27;380:e069717. PubMed 36849186
2. Barbhaiya M, Zuily S, Naden R, et al. The 2023 ACR/EULAR antiphospholipid syndrome classification criteria. Arthritis Rheumatol. 2023 Oct;75(10):1687-1702. PubMed 37635643
3. Vandevelde A, Devreese KMJ. Laboratory diagnosis of antiphospholipid syndrome: insights and hindrances. J Clin Med. 2022 Apr 13;11(8):2164. PubMed 35456258
4. Devreese KMJ, de Groot PG, de Laat B, et al. Guidance from the Scientific and Standardization Committee for lupus anticoagulant /antiphospholipid antibodies of the International Society on Thrombosis and Haemostasis: Update of the guidelines for lupus anticoagulant detection and interpretation. J Thromb Haemost. 2020 Nov;18(11):2828-2839. PubMed 33462974
5. Devreese KM, Ortel TL, Pengo V, de Laat B. Laboratory criteria for antiphospholipid syndrome: reply. J Thromb Haemost. 2018 Oct;16(10):2117-2119. PubMed 30007111
6. Keeling D, Mackie I, Moore GW, Greaves M, British Committee for Standards in Haemotology. Guidelines on the investigation and management of antiphospholipid syndrome. Br J Haematol. 2012 Apr;157(1):47-58. PubMed 22313321
7. Pengo V, Tripodi A, Reber G, et al. Update of the guidelines for lupus anticoagulant detection. Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Haemostasis. J Thromb Haemost. 2009 Oct;7(10):1737-1740. PubMed 19624461
8. Miyakis S, Lockshin MD, Atsumi T, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost. 2006 Feb;4(2):295-306. PubMed 16420554
9. Vandevelde A, Devreese KMJ. Laboratory Diagnosis of Antiphospholipid Syndrome: Insights and Hindrances. J Clin Med. 2022 Apr 13;11(8):2164. PubMed 35456258
10. Favaloro EJ, Pasalic L, Selby R. Testing for the lupus anticoagulant: the good, the bad, and the ugly. Res Pract Thromb Haemost. 2024 Mar 18;8(3):102385. PubMed 38623474
11. Abreu MM, Danowski A, Wahl DG, et al. The relevance of "non-criteria" clinical manifestations of antiphospholipid syndrome: 14th International Congress on Antiphospholipid Antibodies Technical Task Force Report on Antiphospholipid Syndrome Clinical Features. Autoimmun Rev. 2015 May;14(5):401-414. PubMed 25641203
12. Bernardoff I, Picq A, Loiseau P, et al. Antiphospholipid antibodies and the risk of autoimmune hemolytic anemia in patients with systemic lupus erythematosus: A systematic review and meta-analysis. Autoimmun Rev. 2022 Jan;21(1):102913. PubMed 34371159
13. Chock YP, Moulinet T, Dufrost V, Erkan D, Wahl D, Zuily S. Antiphospholipid antibodies and the risk of thrombocytopenia in patients with systemic lupus erythematosus: A systematic review and meta-analysis. Autoimmun Rev. 2019 Nov;18(11):102395. PubMed 31520800
14. Zuily S, Regnault V, Selton-Suty C, et al. Increased risk for heart valve disease associated with antiphospholipid antibodies in patients with systemic lupus erythematosus: meta-analysis of echocardiographic studies. Circulation. 2011 Jul 12;124(2):215-224. PubMed 21690492
15. Clinical and Laboratory Standards Institute (CLSI). Laboratory testing for the lupus anticoagulant; approved guideline. CLSI document H60-A. Wayne, PA. CLSI; 2014.
16. Tripodi A, Chantarangkul V. Lupus anticoagulant testing: activated partial thromboplastin time (APTT) and silica clotting time (SCT). Methods Mol Biol. 2017;1646:177-183. PubMed 28804829
17. Pengo V, Bison E, Banzato A, Zoppellaro G, Jose SP, Denas G. Lupus anticoagulant testing: diluted Russell Viper venom time (dRVVT). Methods Mol Biol. 2017;1646:169-176. PubMed 28804828
18. Simmons DP, Herskovits AZ, Battinelli EM, Schur PM, Lemire SJ, Dorfman DM. Lupus anticoagulant testing using two parallel methods detects additional cases and predicts persistent positivity. Clin Chem Lab Med. 2018 Jul 26;56(8):1289-1296. PubMed 27305702
19. Thiagarajan P, Pengo V, Shapiro SS. The use of the dilute Russell viper venom time for the diagnosis of lupus anticoagulants. Blood. 1986 Oct;68(4):869-874. PubMed 3092888
20. Boekel ET, Böck M, Vrielink GJ, Liem R, Hendriks H, de Kieviet W. Detection of shortened activated partial thromboplastin times: an evaluation of different commercial reagents. Thromb Res. 2007;121(3):361-367. PubMed 17568658
21. Arachchillage DRJ, Gomez K, Alikhan R, et al. Addendum to British Society for Haematology Guidelines on Investigation and Management of Antiphospholipid syndrome, 2012 (Br. J. Haematol. 2012;157:47-58): use of direct acting oral anticoagulants. Br J Haematol. 2020 Apr;189(2):212-215. PubMed 31943138
22. Schouwers SM, Delanghe JR, Devreese KM. Lupus anticoagulant (LAC) testing in patients with inflammatory status: does C-reactive protein interfere with LAC test results? Thromb Res. 2010 Jan;125(1):102-104. PubMed 19782388
23. Tripodi A, Cohen H, Devreese KMJ. Lupus anticoagulant detection in anticoagulated patients. Guidance from the Scientific and Standardization Committee for lupus anticoagulant/antiphospholipid antibodies of the International Society on Thrombosis and Haemostasis. J Thromb Haemost. 2020 Jul;18(7):1569-1575. PubMed 32619349
24. Mehr NA, Storozuk TE, Mikrut KL, Wool GD. The utility of the dilute prothrombin time in the interpretation of antiphospholipid syndrome testing. Am J Clin Pathol. 2024 Oct 3;162(4):379-391. PubMed 38741421
25. De Kesel PMM, Devreese KMJ. The effect of unfractionated heparin, enoxaparin, and danaparoid on lupus anticoagulant testing: Can activated carbon eliminate false-positive results? Res Pract Thromb Haemost. 2019 Dec 10;4(1):161-168. PubMed 31989098
26. Adcock DM, Kressin DC, Marlar RA. Effect of 3.2% vs 3.8% sodium citrate concentration on routine coagulation testing. Am J Clin Pathol. 1997 Jan;107(1):105-110. PubMed 8980376
27. Reneke J, Etzell J, Leslie S, Ng VL, Gottfried EL. Prolonged prothrombin time and activated partial thromboplastin time due to underfilled specimen tubes with 109 mmol/L (3.2%) citrate anticoagulant. Am J Clin Pathol. 1998 Jun;109(6):754-757. PubMed 9620035
28. National Committee for Clinical Laboratory Standardization. Collection, Transport, and Processing of Blood Specimens for Coagulation Testing and General Performance of Coagulation Assays; Approved Guideline. 5th ed. Villanova, Pa. NCCLS; 2008. Document H21-A5:28(5).
29. Gottfried EL, Adachi MM. Prothrombin time and activated partial thromboplastin time can be performed on the first tube. Am J Clin Pathol. 1997 Jun;107(6):681-683. PubMed 9169665
30. McGlasson DL, More L, Best HA, Norris WL, Doe RH, Ray H. Drawing specimens for coagulation testing: Is a second tube necessary? Clin Lab Sci. 1999 May-Jun; 12(3):137-139. PubMed 10539100
31. Abreu MM, Danowski A, Wahl DG, et al. The relevance of "non-criteria" clinical manifestations of antiphospholipid syndrome: 14th International Congress on Antiphospholipid Antibodies Technical Task Force Report on Antiphospholipid Syndrome Clinical Features. Autoimmun Rev. 2015 May;14(5):401-414. PubMed 25641203
32. Conti F, Andreoli L, Crisafulli F, Mancuso S, Truglia S, Tektonidou MG. Does seronegative obstetric APS exist? "pro" and "cons." Autoimmun Rev. 2019 Dec;18(12):102407. PubMed 31639518
33. Devreese KM, Verfaillie CJ, De Bisschop F, Delanghe JR. Interference of C-reactive protein with clotting times. Clin Chem Lab Med. 2015 Apr;53(5):e141-145. PubMed 25324454
34. Ten Boekel E, Bartels P. Abnormally short activated partial thromboplastin times are related to elevated plasma levels of TAT, F1+2, D-dimer and FVIII:C. Pathophysiol Haemost Thromb. 2002 May-Jun;32(3):137-142. PubMed 12372929
35. Kamphuisen PW, Eikenboom JC, Bertina RM. Elevated factor VIII levels and the risk of thrombosis. Arterioscler Thromb Vasc Biol. 2001 May;21(5):731-738. PubMed 11348867
36. Foret T, Dufrost V, Salomon Du Mont L, et al. Systematic Review of Antiphospholipid Antibodies in COVID-19 Patients: Culprits or Bystanders? Curr Rheumatol Rep. 2021 Jul 3;23(8):65. PubMed 34218350
37. Martirosyan A, Aminov R, Manukyan G. Environmental Triggers of Autoreactive Responses: Induction of Antiphospholipid Antibody Formation. Front Immunol. 2019 Jul 10;10:1609. PubMed 31354742
38. Wallin R, Hutson SM. Warfarin and the vitamin K-dependent gamma-carboxylation system. Trends Mol Med. 2004 Jul;10(7):299-302. PubMed 15242675
39. Hemker HC. A century of heparin: past, present and future. J Thromb Haemost. 2016 Dec;14(12):2329-2338. PubMed 27862941
40. Chan N, Sobieraj-Teague M, Eikelboom JW. Direct oral anticoagulants: evidence and unresolved issues. Lancet. 2020 Nov 28;396(10264):1767-1776. PubMed 33248499
41. Antovic A, Norberg EM, Berndtsson M, et al. Effects of direct oral anticoagulants on lupus anticoagulant assays in a real-life setting. Thromb Haemost. 2017 Aug 30;117(9):1700-1704. PubMed 28640321
42. Gay J, Duchemin J, Imarazene M, Fontenay M, Jourdi G. Lupus anticoagulant diagnosis in patients receiving direct oral FXa inhibitors at trough levels: A real-life study. Int J Lab Hematol. 2019 Dec;41(6):738-744. PubMed 31487115
43. Martinuzzo ME, Forastiero R, Duboscq C, et al. False-positive lupus anticoagulant results by DRVVT in the presence of rivaroxaban even at low plasma concentrations. Int J Lab Hematol. 2018 Oct;40(5):e99-e101. PubMed 29809321
44. Favaloro EJ, Mohammed S, Curnow J, Pasalic L. Laboratory testing for lupus anticoagulant (LA) in patients taking direct oral anticoagulants (DOACs): potential for false positives and false negatives. Pathology. 2019 Apr;51(3):292-300. PubMed 30665674
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 164535 | APS Assessment | 117003 | PTT-LA | sec | 34571-0 | |
| 164535 | APS Assessment | 117891 | dRVVT | sec | 6303-2 | |
| 164535 | APS Assessment | 117893 | Lupus Reflex Interpretation | 75514-0 | ||
| 164535 | APS Assessment | 109009 | Thrombin Time | sec | 3243-3 | |
| 164535 | APS Assessment | 161812 | Anticardiolipin Ab,IgG,Qn | GPL U/mL | 3181-5 | |
| 164535 | APS Assessment | 161830 | Anticardiolipin Ab,IgM,Qn | MPL U/mL | 3182-3 | |
| 164535 | APS Assessment | 161838 | Anticardiolipin Ab,IgA,Qn | APL U/mL | 5076-5 | |
| 164535 | APS Assessment | 163881 | Beta-2 Glycoprotein I Ab, IgG | GPI IgG units | 16135-6 | |
| 164535 | APS Assessment | 163899 | Beta-2 Glycoprotein I Ab, IgA | GPI IgA units | 21108-6 | |
| 164535 | APS Assessment | 163907 | Beta-2 Glycoprotein I Ab, IgM | GPI IgM units | 16136-4 | |
| 164535 | APS Assessment | 117927 | Antiphosphatidylserine IgG | Units | 14245-5 | |
| 164535 | APS Assessment | 117910 | Antiphosphatidylserine IgM | Units | 14246-3 | |
| 164535 | APS Assessment | 005201 | Dilute Prothrombin Time(dPT) | sec | 75508-2 | |
| 164535 | APS Assessment | 005203 | dPT Confirm Ratio | Ratio | 75884-7 | |
| 164535 | APS Assessment | 001702 | Fibrinogen Activity | mg/dL | 3255-7 | |
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 117003 | |||||
| Result Code Name | PTT-LA | |||||
| UofM | sec | |||||
| Result LOINC | 34571-0 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 117891 | |||||
| Result Code Name | dRVVT | |||||
| UofM | sec | |||||
| Result LOINC | 6303-2 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 117893 | |||||
| Result Code Name | Lupus Reflex Interpretation | |||||
| UofM | ||||||
| Result LOINC | 75514-0 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 109009 | |||||
| Result Code Name | Thrombin Time | |||||
| UofM | sec | |||||
| Result LOINC | 3243-3 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 161812 | |||||
| Result Code Name | Anticardiolipin Ab,IgG,Qn | |||||
| UofM | GPL U/mL | |||||
| Result LOINC | 3181-5 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 161830 | |||||
| Result Code Name | Anticardiolipin Ab,IgM,Qn | |||||
| UofM | MPL U/mL | |||||
| Result LOINC | 3182-3 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 161838 | |||||
| Result Code Name | Anticardiolipin Ab,IgA,Qn | |||||
| UofM | APL U/mL | |||||
| Result LOINC | 5076-5 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 163881 | |||||
| Result Code Name | Beta-2 Glycoprotein I Ab, IgG | |||||
| UofM | GPI IgG units | |||||
| Result LOINC | 16135-6 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 163899 | |||||
| Result Code Name | Beta-2 Glycoprotein I Ab, IgA | |||||
| UofM | GPI IgA units | |||||
| Result LOINC | 21108-6 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 163907 | |||||
| Result Code Name | Beta-2 Glycoprotein I Ab, IgM | |||||
| UofM | GPI IgM units | |||||
| Result LOINC | 16136-4 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 117927 | |||||
| Result Code Name | Antiphosphatidylserine IgG | |||||
| UofM | Units | |||||
| Result LOINC | 14245-5 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 117910 | |||||
| Result Code Name | Antiphosphatidylserine IgM | |||||
| UofM | Units | |||||
| Result LOINC | 14246-3 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 005201 | |||||
| Result Code Name | Dilute Prothrombin Time(dPT) | |||||
| UofM | sec | |||||
| Result LOINC | 75508-2 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 005203 | |||||
| Result Code Name | dPT Confirm Ratio | |||||
| UofM | Ratio | |||||
| Result LOINC | 75884-7 | |||||
| Order Code | 164535 | |||||
| Order Code Name | APS Assessment | |||||
| Order Loinc | ||||||
| Result Code | 001702 | |||||
| Result Code Name | Fibrinogen Activity | |||||
| UofM | mg/dL | |||||
| Result LOINC | 3255-7 |
| Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
|---|---|---|---|---|---|---|
| Reflex 1 | 117040 | PTT-LA Mix | 117005 | PTT-LA Mix | sec | 75510-8 |
| Reflex 2 | 117020 | Hexagonal Phase Phospholipid | 117842 | Hexagonal Phase Phospholipid | sec | 3282-1 |
| Reflex 1 | ||||||
| Order Code | 117040 | |||||
| Order Name | PTT-LA Mix | |||||
| Result Code | 117005 | |||||
| Result Name | PTT-LA Mix | |||||
| UofM | sec | |||||
| Result LOINC | 75510-8 | |||||
| Reflex 2 | ||||||
| Order Code | 117020 | |||||
| Order Name | Hexagonal Phase Phospholipid | |||||
| Result Code | 117842 | |||||
| Result Name | Hexagonal Phase Phospholipid | |||||
| UofM | sec | |||||
| Result LOINC | 3282-1 | |||||