Test Catalog

Test Id : AVWPI

von Willebrand Disease Profile Technical Interpretation

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detection of deficiency or abnormality of von Willebrand factor (VWF) and related deficiency of factor VIII coagulant activity

 

Subtyping von Willebrand disease (VWD) as type 1 (most common), type 2 variants (less common), or type 3 (rare)

 

This test is not useful for detection of hemophilia carriers.

 

This test is not useful for differentiating type 2A versus 2B VWD or platelet-type VWD (pseudo-VWD).

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If the factor VIII, von Willebrand factor (VWF) antigen, VWF activity and VWF activity:VWF antigen ratio are normal, a computer-generated interpretive comment indicating no evidence of von Willebrand disease will be provided.

 

If any test results in the profile are abnormal, all results will be reviewed by a coagulation consultant and a von Willebrand Disease Profile Interpretation (AVWPQ) will be provided.

Method Name
A short description of the method used to perform the test

Only orderable as part of a profile. For more information see AVWPR / von Willebrand Disease Profile, Plasma.

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

von Willebrand Disease Tech Interp

Aliases
Lists additional common names for a test, as an aid in searching

Coag

von Willebrand Profile

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If the factor VIII, von Willebrand factor (VWF) antigen, VWF activity and VWF activity:VWF antigen ratio are normal, a computer-generated interpretive comment indicating no evidence of von Willebrand disease will be provided.

 

If any test results in the profile are abnormal, all results will be reviewed by a coagulation consultant and a von Willebrand Disease Profile Interpretation (AVWPQ) will be provided.

Specimen Type
Describes the specimen type validated for testing

Plasma Na Cit

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Only orderable as part of a profile. For more information see AVWPR / von Willebrand Disease Profile, Plasma.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

1 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen (preferred) 14 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detection of deficiency or abnormality of von Willebrand factor (VWF) and related deficiency of factor VIII coagulant activity

 

Subtyping von Willebrand disease (VWD) as type 1 (most common), type 2 variants (less common), or type 3 (rare)

 

This test is not useful for detection of hemophilia carriers.

 

This test is not useful for differentiating type 2A versus 2B VWD or platelet-type VWD (pseudo-VWD).

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If the factor VIII, von Willebrand factor (VWF) antigen, VWF activity and VWF activity:VWF antigen ratio are normal, a computer-generated interpretive comment indicating no evidence of von Willebrand disease will be provided.

 

If any test results in the profile are abnormal, all results will be reviewed by a coagulation consultant and a von Willebrand Disease Profile Interpretation (AVWPQ) will be provided.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

von Willebrand factor (VWF) is synthesized by the endothelial cell and megakaryocyte and is present in these cells, as well as in platelets, subendothelial tissue, and plasma.

 

VWF serves as an adhesive protein important in adhering platelets to subendothelial tissue at the site of vascular injury and for adhering platelets to each other (aggregation). Platelet adhesion and aggregation are essential to form a mechanical hemostatic "plug" and as the focus for interaction of clotting factors and phospholipid required for the formation of the fibrin platelet clot. VWF also stabilizes plasma factor VIII by binding it and protecting it from proteolysis and serves as a carrier protein for that clotting factor.

 

VWF circulates in the blood in 2 distinct compartments. Plasma VWF mainly reflects VWF synthesis and release from vascular endothelial cells. Platelet VWF (about 10% of the blood VWF) reflects VWF synthesis by bone marrow megakaryocytes with storage primarily in the alpha granules of circulating platelets.

 

Plasma VWF circulates normally in multimeric forms with molecular weights ranging from 500,000 to as much as 20,000,000. The high-molecular-weight (HMW) forms of VWF are the most effective components for interaction with platelets. This primary activity of plasma VWF is measured in the laboratory with the VWF activity assay, whereas VWF antigen testing measures the amount of VWF protein, and factor VIII coagulant activity indirectly reflects VWF interaction with factor VIII. VWF multimer analysis visualizes the distribution of VWF multimers and is useful as a reflexive test for subtyping von Willebrand disease (VWD).

 

Levels of factor VIII, VWF antigen, and VWF activity may vary greatly within each individual over time and also with blood type (normal type "O" individuals may have VWF lower than normals of other blood groups). VWF levels (and factor VIII) can be elevated in liver disease, pregnancy, estrogen therapy, inflammation, and after exercise (acute-phase reactant). VWF levels in hemophilia are normal.

 

VWF antigen measurement assesses the mass of plasma VWF protein, but does not reflect VWF functions or platelet VWF. The function of VWF (mediating platelet-platelet or platelet-vessel interaction) is most commonly assessed by measurement of plasma VWF activity.

 

VWD is the most common inherited bleeding disorder, affecting up to 1% of the population. It can also occur as an acquired bleeding disorder. Bleeding symptoms in all types of VWD are primarily mucosal, including epistaxis, menorrhagia, gastrointestinal bleeding, and ease of bruising, but surgical or posttraumatic bleeding can also occur.

 

Subtypes of inherited VWD are:

Type 1 VWD:

VWF plasma levels (antigen and activity) typically are both concordantly reduced in type 1 VWD. Because of this reduction, the level of coagulation factor VIII is often secondarily reduced also. Type 1 VWD is the most common VWD variation, representing 70% to 80% of clinical VWD. It is typically inherited in autosomal dominance fashion, although recessively inherited VWD also occurs (eg, type 3 VWD). Clinical severity ranges from mild or minimal to a moderately severe bleeding diathesis, and tends to correlate most closely with VWF activity. Severe type 1 disease is also called type 3 VWD, but the distinction between the two may sometimes be difficult.

 

Type 2 VWD:

Type 2 VWD variants represent 20% to 30% of clinical VWD, typically autosomal dominant in inheritance. There are 4 subtypes of type 2 VWD: 2A, 2B, 2M, and 2N. Abnormal plasma HMW VWF function and multimeric structure with decreased or absent HMW multimers are characteristic of types 2A and 2B, but are normal in type 2M or 2N.

 

VWF activity is decreased in types 2A, 2B, and 2M, and typically is discordantly lower than VWF antigen. Type 2N (Normandy) has substantially decreased factor VIII coagulant activity (typically 5%-30% of mean normal), with normal VWF antigen and activity and normal VWF multimers with clinical manifestation as autosomally inherited mild hemophilia (in contrast to classical X chromosome-linked hemophilia A).

 

Type 2A is the most common of the 4. Type 2B manifests thrombocytopenia, either persistent or transient, and is distinguished from type 2A by abnormally heightened aggregation response of patient platelets and plasma to low dose ristocetin stimulation. Type 2M typically demonstrates hypofunctional VWF with decreased VWF activity discordantly lower than VWF antigen not due to loss of HMW multimers. One variant of type 2M, Vicenza variant VWD, has ultralarge VWF multimers in plasma.

 

Type 3 VWD:

VWF is absent or markedly decreased in type 3 VWD (VWF antigen and activity either undetectably low or below 5% to 10% of mean normal), with secondary decrease of factor VIII coagulant activity (5%-30%). VWF multimers may be undetectable or, if present, have a normal distribution. Platelet VWF may also be absent.

 

Acquired VWD:

VWD can also occur on an acquired basis by a variety of mechanisms not well understood. Disorders associated with acquired VWD include certain myeloproliferative or lymphoproliferative disorders, plasma cell dyscrasias including monoclonal gammopathy of undetermined significance, autoimmune disorders (eg, rheumatoid arthritis, systemic lupus erythematosus), and a variety of other diseases. In some cases, no associated disorder is detected. Laboratory testing currently cannot distinguish between congenital and acquired VWD; clinical correlation is required.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Only orderable as part of a profile. For more information see AVWPR / von Willebrand Disease Profile, Plasma.

 

An interpretive report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

An interpretive report will be provided when testing is complete.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Testing should be performed prior to and in the absence of recent transfusion or von Willebrand factor (VWF) replacement therapy, (eg, Humate P or DDAVP [desmopressin]). If the patient has received any such therapy, this information should be provided. von Willebrand disease (VWD) patients receiving Humate P therapy may have a VWF activity level 10% to 20% lower than the VWF ristocetin cofactor activity level. Low normal levels of VWF antigen or activity do not exclude possible diagnosis of VWD (repeat testing may be indicated). Use of estrogens may result in a mild increase in VWF levels, thus masking a diagnosis of mild VWD.

 

Borderline low or slightly decreased levels of VWF antigen or activity may be observed in clinically normal individuals of blood group O.

 

This test is not useful for differentiating type 2A versus 2B VWD or platelet-type VWD (pseudo-VWD). This differentiation requires ristocetin-induced platelet aggregation testing, which must be performed using freshly obtained patient platelets and plasma.

 

Clinical correlation is required for differentiating acquired from congenital (hereditary) forms of VWD. Repeat testing may be helpful for confirming or evaluating low or borderline low levels of VWF (antigen and activity), especially when there is strong suspicion of VWD.

 

The milder forms of the disease, especially type 1 VWD, can be difficult to diagnose or exclude, reflecting the variability of baseline VWF levels. In addition to demonstration of persistently decreased levels of VWF, clinical correlation is required for diagnosis of all VWD subtypes, especially mild type 1 VWD.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Federici AB, Mannucci PM: Advances in the genetics and treatment of von Willebrand disease. Curr Opin Pediatr 2002 Feb;14(1):23-33

2. Budde U, Schneppenheim R: von Willebrand factor and von Willebrand disease. Rev Clin Exp Hematol 2001 Dec;5(4):335-368

3. Kumar S, Pruthi RK, Nichols WL: Acquired von Willebrand disease. Mayo Clin Proc 2002 Feb;77(2):181-187

Method Description
Describes how the test is performed and provides a method-specific reference

If the factor VIII, von Willebrand factor (VWF) antigen, VWF activity and VWF activity:VWF antigen ratio are normal, a computer-generated interpretive comment indicating no evidence of von Willebrand disease will be provided.(Unpublished Mayo method)

 

If any test results in the profile are abnormal, all results will be reviewed by a coagulation consultant and a von Willebrand Disease Profile Interpretation (AVWPQ) will be provided.

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Varies

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

Not Applicable

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

85390

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
AVWPI von Willebrand Disease Tech Interp 48595-3
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
AVWPI von Willebrand Disease Tech Interp 48595-3

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports