TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: VWFNG    
von Willebrand Disease, VWF Gene, Next-Generation Sequencing, Varies

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

A clinical and laboratory testing algorithm for von Willebrand disease (VWD) has been developed by the National Heart, Lung, and Blood Institute of the National Institutes of Health that is freely available at https://www.nhlbi.nih.gov/health-pro/guidelines/current/von-willebrand-guidelines.

 

The laboratory workup for VWD is complex and requires initial coagulation screening (including a CBC, platelet count, partial thromboplastin time (PTT), prothrombin time (PT), and fibrinogen or thrombin time) should be performed prior to any consideration of genetic testing. Genetic testing should not be performed until a definitive diagnosis of VWD has been made.

 

Prenatal genetic testing is not performed without the prior identification of familial VWF alterations.

 

For any cord blood or prenatal specimen that is received, maternal cell contamination studies will be added. A maternal whole blood sample is required to perform this test.

 

If amniotic fluid is received, amniotic fluid culture will be added and charged separately. If chorionic villus specimen is received, fibroblast culture will be added and charged separately.

Specimen Type Describes the specimen type validated for testing

Varies

Ordering Guidance

Genetic testing should only be considered if clinical and family history, initial coagulation screens, initial von Willebrand factor (VWF) tests (antigen, ristocetin cofactor, and factor VIII coagulant activity), and specialized nongenetic VWF studies indicate a diagnosis of VWD.

Additional Testing Requirements

Due to the complexity of testing non-peripheral blood, consultation with the laboratory is required for all cord blood samples. All cord blood specimens must be accompanied by a maternal blood specimen. Order this test on the cord blood specimen (only 1 sample tube required) and order MATCC / Maternal Cell Contamination, Molecular Analysis, Blood on the maternal specimen.

Shipping Instructions

Prenatal Specimens: Advise Express Mail or equivalent if not on courier service. Prenatal specimens can be sent Monday through Thursday and must be received by 3 p.m. CST on Friday in order to be processed appropriately.

Blood: Ambient and refrigerate specimens must arrive within 7 days and frozen specimens must arrive within 14 days .

Collect and package specimen as close to shipping time as possible.

Necessary Information

von Willebrand Disease Patient Information is required, see Special Instructions. Testing may proceed without the patient information, however, the information aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.

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

Results will be reported and also telephoned or faxed, if requested.

 

Submit only 1 of the following specimens:

 

Specimen Type: Peripheral blood or cord blood

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD) or light-blue top (sodium citrate)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability Information: Ambient (preferred) 7 days/Refrigerated 7 days/Frozen 14 days

 

Due to the complexity of prenatal testing, consultation with the laboratory is required for all prenatal testing.

 

Specimen Type: Amniotic fluid

Supplies: Refrigerate/Ambient Mailer, 5 lb (T329)

Container/Tube: Amniotic fluid container

Specimen Volume: 10-20 mL

Collection Instructions:

1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted.

2. Discard the first 2 mL of amniotic fluid.

3. Place the tubes in a Styrofoam container.

4. Fill remaining space with packing material.

5. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.

6. Bloody specimens are undesirable.

7. If the specimen does not grow in culture, you will be notified within 7 days of receipt.

Additional Information:

A separate culture charge will be assessed under CULAF / Amniotic Fluid Culture for Genetic Testing

Specimen Stability Information: Refrigerated (preferred) <24 hours/Ambient <24 hours

 

Specimen Type: Chorionic villi

Supplies: CVS Media (RPMI) and Small Dish (T095)

Container/Tube: 15-mL tube containing 15 mL of transport media

Specimen Volume: 20-30 mg

Collection Instructions:

1. Collect specimen by the transabdominal or transcervical method.

2. Transfer the chorionic villi specimen to a Petri dish containing transport medium.

3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi and remove any blood clots and maternal decidua.

Additional Information:

A separate culture charge will be assessed under CULFB / Fibroblast Culture for Genetic Testing

Specimen Stability Information: Refrigerated (preferred) <24 hours/Ambient <24 hours

 

Specimen Type: Confluent cultured cells

Container/Tube: T-25 flask

Specimen Volume: 2 Flasks approximately 90% confluent

Collection Instructions: Submit confluent cultured cells from another laboratory

Additional Information: There will be no culture charge.

Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated <24 hours

Special Instructions Library of PDFs including pertinent information and forms related to the test

Forms

1. von Willebrand Disease Patient Information (T825) is required, see Special Instructions.

2. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

3. If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.

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

Blood: 1 mL
Amniotic fluid: 10 mL
Chorionic villi: 10 mg
Confluent cultured cells: 2 full flasks

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

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

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 TypeTemperatureTimeSpecial Container
VariesVaries