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


Advisory Information


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


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


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.

Useful For

Genetic confirmation of hereditary von Willebrand disease with the identification of alterations in the VWF gene known or suspected to cause the condition

 

Testing for close family members of an individual with a von Willebrand disease diagnosis

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CULAF Amniotic Fluid Culture/Genetic Test Yes No
CULFB Fibroblast Culture for Genetic Test Yes No
MATCC Maternal Cell Contamination, B Yes No

Testing Algorithm

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.

Method Name

Custom Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing when appropriate

Reporting Name

VWF Gene, Full Gene NGS

Specimen Type

Varies

Specimen Minimum Volume

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

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Performed weekly, Varies

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81408

LOINC Code Information

Test ID Test Order Name Order LOINC Value
VWFNG VWF Gene, Full Gene NGS 41768-3

 

Result ID Test Result Name Result LOINC Value
113117 VWFNG Result 50397-9
113111 Alterations Detected 82939-0
113109 Interpretation 69047-9
113112 Additional Information 48767-8
113113 Method 85069-3
113114 Disclaimer 62364-5
113115 Panel Gene List 40970-6
113116 Reviewed By 18771-6