Test Details
Methodology
The Sebia Hydragel™ assay employs an agarose gel for the separation of plasma proteins according to their molecular weight. The electrophoretic separation is carried out after sample treatment with an anionic detergent. This treatment disrupts the three-dimensional structure of the plasma VWF, allowing for the electrophoretic separation of the multimers based on their molecular weight. The system can reveal the loss or retention of HMWM and also intermediate MWM (IMWM) and thus serve as an aid in the characterization of the majority of VWD cases, for example, distinguishing samples with loss of HMWM (and potentially IMWM) (being type 2A, 2B or PT-VWD) from samples without loss of HMWM and/or IMWM (being type 1, 2M, 2N VWD or normal samples), from samples without VWF (i.e., type 3 VWD).1,2
von Willebrand Factor Antigen and Activity levels are measured in order to determine dilution needed for the multimer analysis and as an aid in interpretation of multimer pattern.
Result Turnaround Time
5 - 7 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 von Willebrand factor activity (VWF:Ag); von Willebrand factor antigen (VWF:Ac); VWF:Ag/ VWF:Ac ratio; and von Willebrand Multimer results including percent Intermediate and High Molecular Weight Fractions.
Use
This test is used to measure the relative levels of von Willebrand low molecular weight multimers (LMWM), intermediate molecular weight multimers (IMWM) and high molecular weight multimers (HMWM) in plasma.
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Custom Additional Information
Von Willebrand Disease (VWD) is the most common congenital bleeding disorder and arises from deficiency and/or defect in plasma von Willebrand Factor (VWF).1-4 Three main VWD types are recognized, with six sub-types (1, 2A, 2B, 2M, 2N, 3) identified according to current International Society on Thrombosis and Haemostasis (ISTH) classification.2-4 Types 1 and 3 identify quantitative deficiency of VWF, respectively partial or (virtually) total. In Types 1 and 3, any VWF present is functionally normal, albeit deficient in quantity. Type 2 VWD defines qualitative defects of VWF, although VWF levels are also quantitatively low in many patients. Type 2A VWD identifies patients with a specific loss of high molecular weight multimers of VWF (HMWM), the VWF form that has greatest specific adhesive activity. Type 2A VWD patients suffer from loss of VWF activity binding to both platelets (primarily via glycoprotein lb; GPlb) and subendothelial matrix components (predominantly collagen). Type 2B VWD identifies patients with hyper-functional VWF, which spontaneously binds platelets, thereby causing clearance of (predominantly HMWM) VWF and platelets from circulation and often a (mild) thrombocytopenia. Type 2N VWD reflects a loss of VWF-FVIII binding; thus, increasing FVIII susceptibility to degradation and reducing plasma FVIII levels. Type 2M VWD reflects a heterogeneous group with defective VWF not associated with loss of HMWM.
In addition to clinical assessment of patients, VWD diagnosis is supported by laboratory testing.2-5 A standard test panel recommended by most guidelines involves measurement of VWF antigen (VWF:Ag), VWF GP1b binding activity (VWF:Ac) and factor VIII activity (FVIII). VWF:Ag testing is important due to complexity and heterogeneity of VWD and permits quantifying absolute levels of (total) VWF protein. VWF:Ac measurement assesses the extent to which the VWF in the sample can bind GP1b, reflecting diminished HMWM and/or genetic defect compromising this function. FVIII testing is important since one major function of VWF is to bind and protect FVIII from degradation. Thus, FVIII is often low in VWD a condition that contributes to any bleeding diathesis (especially types 3, 2N and severe type 1 VWD). Additional assays may be used to support the diagnosis of VWD. VWF collagen binding activity (VWF:CB) is also recommended in guidelines.2,6 In vivo, collagen binding permits anchorage of platelets to damaged endothelium, enabling VWF to act as an adhesive bridge to capture platelets. Assessment of VWF multimers is also useful, particularly to help identify loss of HMWM (types 2A or 2B VWD), and potentially discriminate these from types without such loss (type 1 or 2M VWD).
The formation of VWF in vivo begins with inter-subunit carboxyl termini disulphide bond linkage of “pre-VWF” protein to form a multimeric protein.7 This “tail-to-tail” dimerization continues through multiple cycles to create a large multimeric protein.7 In vivo biosynthesis of VWF is limited to endothelial cells and megakaryocytes. After “construction,” mature VWF exits in the plasma as a series of oligomers containing a variable number of subunits, ranging from a minimum of two to a maximum of 40, with the largest multimers having molecular weights in excess of 20,000 kDa.8 The largest multimers have the greatest overall adhesive or functional ability since these contain the greatest number of overall binding sites for GPIb, collagen and FVIII. The larger multimers have been said to act like a “sticky string.”9 The longer the VWF molecule (the higher the number of linked subunits), the greater the adhesion of this VWF to platelets (i.e., GPIb) and to damaged sub-endothelium (i.e., collagen). Consequently, the higher molecular weight multimers (HMWM) do a better job of tying platelets to the site of injury like a rope tethering a balloon.
The laboratory can visualize the multimeric pattern of plasma VWF by performing VWF multimer analysis.10 This analysis separates VWF by electrophoresis into different multimer sizes. This allows the determination of the amount of HMWM, intermediate (IMWM) and low molecular weight (LMWM) multimers present in the sample. A recently developed, commercially available semi-automated assay for analysis of VWF multimer distribution has been validated in a number of clinical publications.11-23
Specimen Requirements
Specimen
Plasma, frozen
Volume
2.0 mL
Minimum Volume
1.0 mL (Note: This volume does not allow for repeat testing.)
Container
Blue stopper 3.2% sodium citrate plasma evacuated tube
Collection Instructions
Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.24 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.25,26 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set, a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube.27,28 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 alternative 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.
Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Reference Range
| Molecular Weight | Percent |
|---|---|
| Intermediate Molecular Weight vWF | 25.0–50.0 |
| High Molecular Weight vWF | 45.0–65.0 |
Storage Instructions
Freeze; four freeze/thaw cycles are acceptable. Stable refrigerated for four hours.
Causes for Rejection
Lipemia; icteric specimen; hemolysis; clotted specimen; specimen contaminated with heparin (i.e., drawn with blood gases)
Footnotes
1. Favaloro EJ, Mohammed S, Vong R, et al. How we diagnose 2M von Willebrand disease (VWD): use of a strategic algorithmic approach to distinguish 2M VWD from other VWD types. Haemophilia. 2021 Jan;27(1):137-148. PubMed 33215808
2. James PD, Connell NT, Ameer B, et al. ASH ISTH NHF WFH 2021 guidelines on the diagnosis of von Willebrand disease. Blood Adv. 2021 Jan 12;5(1):280-300. PubMed 33570651
3. Patton S, Baker P, Bowyer A, et al. Guideline for laboratory diagnosis and monitoring of von Willebrand disease: a joint guideline from the United Kingdom haemophilia Centre Doctors` organization and the British Society for haematology. Br J Haematol. 2024 May;204(5):1714-1731. PubMed 38532595
4. Kaur V, Elghawy O, Deshpande S, Riley D. von Willebrand disease: A guide for the internist. Cleve Clin J Med. 2024 Feb 2;91(2):119-127. PubMed 38307601
5. Patzke J, Binder NB, Bono M, et al. Review of laboratory methods used for analysis of von Willebrand factor and for diagnosis of related diseases. Expert Rev Hematol. 2025 Jul 4:1-15. PubMed 40613465
6. Laffan MA, Lester W, O'Donnell JS, et al. The diagnosis and management of van Willebrand disease: a United Kingdom Haemophilia Centre Doctors Organization guideline approved by the British Committee for Standards in Haematology. Br J Haematol. 2014 Nov;167:453-465. PubMed 25113304
7. Sadler JE, Budde U, Eikenboom JC, et al. Update on the pathophysiology and classification of von Willebrand disease: a report of the Subcommittee on von Willebrand Factor. J Thromb Haemost. 2006 Oct;4(10):2103-2114. PubMed 16889557
8. Lippok S, Obser T, Muller JP, et al. Exponential size distribution of von Willebrand factor. Biophys J. 2013 Sep 3;105(5):1208-1216. PubMed 24010664
9. Favaloro EJ. The Role of the von Willebrand Factor Collagen-Binding Assay (VWF:CB) in the Diagnosis and Treatment of von Willebrand Disease (VWD) and Way Beyond: A Comprehensive 36-Year History. Semin Thromb Hemost. 2024 Feb;50(1):43-80. PubMed 36807283
10. Favaloro EJ, Oliver S. Evaluation of a new commercial von Willebrand factor multimer assay. Haemophilia. 2017 Jul;23(4):e373-e377. PubMed 28497866
11. Hamiko M, Gerdes L, Silaschi M, et al. Investigation of von Willebrand factor multimer abnormalities before and after aortic valve replacement using the Hydragel-5 assay. Thromb Res. 2024 Sep;241:109094. PubMed 38991494
12. Kimiaei A, Pruner I, Farm M, et al. Ratio of Von Willebrand Collagen Binding Assay and Von Willebrand Antigen Can Predict Multimer Size in Von Willebrand Disease. Haemophilia. 2025 May;31(3):450-457. PubMed 40052420
13. Falter T, Rossmann H, de Waele L, et al. A novel von Willebrand factor multimer ratio as marker of disease activity in thrombotic thrombocytopenic purpura. Blood Adv. 2023;7(17):5091-5102. PubMed 37399489
14. Pikta M, Vasse M, Smock KJ, et al. Establishing reference intervals for von Willebrand factor multimers. J Med Biochem. 2022 Feb 2;41(1):115-121. PubMed 35431650
15. Skornova I, Simurda T, Stasko J, et al. Multimer analysis of von Willebrand factor in von Willebrand disease with a hydrasys semiautomatic analyzer-single-center experience. Diagnostics (Basel). 2021 Nov 20;11(11):2153. PubMed 34829500
16. Pikta M, Szanto T, Viigimaa M, et al. Evaluation of a new semi-automated Hydragel 11 von Willebrand factor multimers assay kit for routine use. J Med Biochem. 2021 Mar 12;40(2):167-172. PubMed 33776566
17. Favaloro EJ, Oliver S, Mohammed S, Vong R. Comparative assessment of von Willebrand factor multimers vs activity for von Willebrand disease using modern contemporary methodologies. Haemophilia. 2020 May;26(3):503-512. Pubmed 32159272
18. Vangenechten I, Gadisseur A. Improving diagnosis of von Willebrand disease: Reference ranges for von Willebrand factor multimer distribution. Res Pract Thromb Haemost. 2020 Jul 16;4(6):1024-1034. PubMed 32864553
19. Oliver S, Vanniasinkam T, Mohammed S, Vong R, Favaloro EJ. Semi-automated von Willebrand factor multimer assay for von Willebrand disease: further validation, benefits and limitations. Int J Lab Hematol. 2019 Dec;41(6):762-771. PubMed 31508897
20. Crist RA, Heikal NM, Rodgers GM, Grenache DG, Smock KJ. Evaluation of a new commercial method for von Willebrand factor multimeric analysis. Int J Lab Hematol. 2018 Oct;40(5):586-591. PubMed 29920949
21. Bowyer AE, Goodfellow KJ, Seidel H, et al. Evaluation of a semi-automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European centers. Res Pract Thromb Haemost. 2018 Aug 12;2(4):790-799. PubMed 30349898
22. Oliver S, Lau KKE, Chapman K, Favaloro EJ. Laboratory testing for von Willebrand factor multimers. Methods Mol Biol. 2017;1646:495-511. PubMed 28804850
23. Favaloro EJ, Oliver S. Evaluation of a new commercial von Willebrand factor multimer assay. Haemophilia. 2017 Jul;23(4):e373-e377. PubMed 28497866
24. 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
25. 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
26. 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).
27. Gottfried EL, Adachi MM. Prothrombin time and activated partial thromboplastin time can be performed on the first tube. Am J Clin Pathol. 1997;107(6):681-683. PubMed 9169665
28. 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
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 117245 | vWF Multimers | 086280 | vWF Antigen | % | 27816-8 | |
| 117245 | vWF Multimers | 164509 | vWF Activity | % | 107372-5 | |
| 117245 | vWF Multimers | 086289 | vWF Activity/Antigen | Ratio | 81643-9 | |
| 117245 | vWF Multimers | 117248 | Low MW vWF | % | Pending | |
| 117245 | vWF Multimers | 117246 | Intermediate MW vWF | % | Pending | |
| 117245 | vWF Multimers | 117247 | High MW vWF | % | 52754-9 | |
| 117245 | vWF Multimers | 086291 | Interpretation | 48595-3 | ||
| Order Code | 117245 | |||||
| Order Code Name | vWF Multimers | |||||
| Order Loinc | ||||||
| Result Code | 086280 | |||||
| Result Code Name | vWF Antigen | |||||
| UofM | % | |||||
| Result LOINC | 27816-8 | |||||
| Order Code | 117245 | |||||
| Order Code Name | vWF Multimers | |||||
| Order Loinc | ||||||
| Result Code | 164509 | |||||
| Result Code Name | vWF Activity | |||||
| UofM | % | |||||
| Result LOINC | 107372-5 | |||||
| Order Code | 117245 | |||||
| Order Code Name | vWF Multimers | |||||
| Order Loinc | ||||||
| Result Code | 086289 | |||||
| Result Code Name | vWF Activity/Antigen | |||||
| UofM | Ratio | |||||
| Result LOINC | 81643-9 | |||||
| Order Code | 117245 | |||||
| Order Code Name | vWF Multimers | |||||
| Order Loinc | ||||||
| Result Code | 117248 | |||||
| Result Code Name | Low MW vWF | |||||
| UofM | % | |||||
| Result LOINC | Pending | |||||
| Order Code | 117245 | |||||
| Order Code Name | vWF Multimers | |||||
| Order Loinc | ||||||
| Result Code | 117246 | |||||
| Result Code Name | Intermediate MW vWF | |||||
| UofM | % | |||||
| Result LOINC | Pending | |||||
| Order Code | 117245 | |||||
| Order Code Name | vWF Multimers | |||||
| Order Loinc | ||||||
| Result Code | 117247 | |||||
| Result Code Name | High MW vWF | |||||
| UofM | % | |||||
| Result LOINC | 52754-9 | |||||
| Order Code | 117245 | |||||
| Order Code Name | vWF Multimers | |||||
| Order Loinc | ||||||
| Result Code | 086291 | |||||
| Result Code Name | Interpretation | |||||
| UofM | ||||||
| Result LOINC | 48595-3 |