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von Willebrand Factor (vWF) Activity

Test Number 164509
Test number copied
CPT

85245

Test Details

Methodology

This assay measures the ability of patient vWF to bind to platelet glycoprotein Ib (GPIb).6 The assay employs a recombinant GPIb genetically modified to include two gain-of-function mutations (GP1bM). These gain-of-function mutations allow for the measurement of vWF binding to GPIb without addition of ristocetin.11

Result Turnaround Time

1 - 3 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.

Related Information

Related Documents

For more information, please view the literature below.

Test Includes

This test includes quantitative von Willebrand Factor (vWF) Activity.

Use

This test is an aid used in the evaluation of patients with suspected or confirmed von Willebrand factor disorders.6,8-12

Special Instructions

If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions.

Limitations

Patient samples may contain heterophile antibodies [e.g., human anti-mouse antibodies (HAMAs) or rheumatoid factors] that could react in antibody using assays to give a falsely elevated (observed more often) or depressed result.6 

This assay has been designed to minimize interference from heterophile antibodies by addition of a blocking reagent. Nevertheless, complete elimination of such an interference from all patient specimens cannot be guaranteed. The diagnosis or exclusion of any type of VWD should therefore never be based solely on the INNOVANCE® VWF Ac result.

Custom Additional Information

See von Willebrand Factor (vWF) Profile [084715] for more clinical information.

Specimen Requirements

Specimen

Plasma (platelet poor), frozen

Volume

1 mL

Container

Blue-top (sodium citrate) tube

Collection Instructions

Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.2,3 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.4,5 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.

Stability Requirements

TemperaturePeriod
Frozen28 days
Freeze/thaw cyclesStable x3

Reference Range

50% to 150%. Average vWF levels tend to vary by blood type.6,8-12 One study found the mean vWF levels by blood type to be as follows:7

• Type O: 74.8%

• Type A: 105.6%

• Type B: 116.9%

• Type AB: 123.3%

Storage Instructions

Freeze.

Patient Preparation

Avoid warfarin (Coumadin®) therapy for two weeks and heparin therapy for two days prior to the test. 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

References

Connell NT, Flood VH, Brignardello-Petersen R, et al. ASH ISTH NHF WFH 2021 guidelines on the management of von Willebrand disease. Blood Adv. 2021 Jan 12;5(1):301-325. PubMed 33570647

Favaloro EJ. Navigating the Myriad of von Willebrand Factor Assays. Hamostaseologie. 2020 Nov;40(4):431-442. PubMed 32590871

Footnotes

1. 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; 107(1):105-110. 8980376
2. Reneke J, Etzell J, Leslie S, et al. 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; 109(6):754-757. 9620035
3. 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).
4. 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. 9169665
5. McGlasson DL, More L, Best HA, et al. Drawing specimens for coagulation testing: Is a second tube necessary? Clin Lab Sci. 1999; 12(3):137-139. 10539100
6. INNOVANCE® VWF Ac on Siemens s BCS® XP System, 11542096_en Rev. 03 – USA only 2022-09 [package insert]. Siemens Healthcare Diagnostics Products GmbH, Emil-von-Behring-Str. 76, 35041 Marburg Germany: siemens-healthineers.com.
7. Gill JC, Endres-Brooks J, Bauer PJ, et al. The effect of ABO blood group on the diagnosis of von Willebrand disease. Blood. 1987; 69(6):1691-1695. 3495304
8. Platton 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' Organisation and the British Society for Haematology. Br J Haematol. 2024 May;204(5):1714-1731. PubMed 38532595
9. 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
10. Rick ME. von Willebrand disease. In: Kitchens CS, Alving BM, Kessler CM, eds. Consultative Hemostasis and Thrombosis. Philadelphia, Pa: WB Saunders Co; 2002:91-102.
11. Bodo I, Eikenboom J, Montgomery R, et al. Platelet-dependent von Willebrand factor activity. Nomenclature and methodology: communication from the SSC of the ISTH. J Thromb Haemost. 2015 Jul;13:1345-1350. PubMed 25858564
12. Liu MC, Kessler CM. A systemic approach to the bleeding patient. In: Kitchens CS, Alving BM, Kessler CM, eds. Consultative Hemostasis and Thrombosis. Philadelphia, Pa: WB Saunders Co; 2002:181-196.

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
164509 vWF Activity 107372-5 164509 vWF Activity % 107372-5
Order Code164509
Order Code NamevWF Activity
Order Loinc107372-5
Result Code164509
Result Code NamevWF Activity
UofM%
Result LOINC107372-5