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VWD-Complete Genetic Panel

Justification

Classical von Willebrand disease (VWD) laboratory work-ups have been shown to require repeat laboratory testing 1 to 20 times to confirm diagnosis. These work-ups include aPTT, factor VIII (8) activity, ristocetin cofactor activity, VWF antigen, ratio calculations, multimeric composition, etc, and each of these tests is influenced by numerous factors such as inflammation, stress, infection, hormone replacement therapy, age, acute phase response, menstrual cycle, pregnancy exercise, ABO blood type, lupus anticoagulant and other factors, making diagnosis challenging. This genetic test will diagnose and subtype von Willebrand disease (VWD) and pseudo- or platelet-type VWD within 1 week (or 48 hours, STAT), with a clinical sensitivity of approximately 85% for subtypes 2A, 2B, 2N, 2M and 3 VWD.

STAT: < 48 hours (M-F)

NGS

Draw Tube: Purple Top

Sample Type: EDTA Whole Blood

DRAW KITS AVAILABLE

Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED EDTA Whole Blood 3mL 1mL Room Temp.: 1 month
Refrigerated: 1 month
ALTERNATIVE Cheek swab 2 swab - Room Temp.: 1 month
Refrigerated: 1 month
REJECTION CRITERIA Sample contamination; sample compromised
SPECIAL INSTRUCTIONS -

General Information

METHODOLOGY NGS
STAT TAT < 48 hours (M-F)
STAT TAT Performance > 90% of results released in 48 hours
ROUTINE TAT < 5 days (M-F)
ALTERNATIVE NAMES von Willebrand disease sequencing, VWF gene sequencing, GP1BA gene sequencing, VWD sequencing, pseudo-VWD sequencing
DESCRIPTION The exons plus 5bp of the flanking introns of VWF and GP1BA are sequenced. Sanger sequencing may be used to confirm variants as needed. VWD occurs with bleeding symptoms at rate of 1 in 1,000 in the general population. In 10% of those cases the bleeding is severe. VWD is the most common congenital bleeding disorder. This genetic test will not detect acquired VWD, estimated to account for 1-5% of cases. Acquired VWD can be evaluated with our von Willebrand Profile test.
LIMITATIONS This test will not detect variants located outside of the targeted DNA regions. This test is not optimized to detect chimerism or somatic mosaicism. This test will detect small indels but may miss larger deletions or duplications. Balanced structural variants will not be detected unless specifically targeted by a custom PCR assay.
NORMAL RANGE Interpretation: Negative
ASSOCIATED TESTING -
REFERENCES

1.) Kirtava A et al. Haemophilia 2004; 10(2):158-161;
2.) Federici, AB. Int Jnl Lab Hem 2016; 38(Suppl.1): 41-49;
3.) Leebeek, FWG and Eikenboom, JCJ. N Engl J Med 2016; 375(21): 2067-2080;
4.) James PD and Lillicrap, D. Br J Haematol 2013; 161: 166-176;
5.) James AH et al. Haemophilia 2016; 22(Suppl. 5): 54-59;
6.) Lillicrap D and James, P. World Federation of Hemophilia 2009; No. 47.
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED No

Test Codes

ORDER CODE P1205
CPT CODE 81479*2
LOINC CODE 94219-3