Orderable EAP code:

LAB00232

Billable EAP Codes:

80001088 x 1

CPT Codes:

85397 x 1

Lab Section:

Hemostasis and Thrombosis

Includes:

This assay is included in Von Willebrand Panel.

Turnaround Time:

1 to 3 days

Test Schedule:

Monday, Wednesday, Friday

Units:

%

Critical Values:

Less than 19%

Specimen Requirements:

Two full 2.7 mL LIGHT BLUE top tube, 3.2% sodium citrate. Specimens must be processed and frozen within 2 hours of specimen collection.

Send 2- 1mL aliquots of platelet poor plasma, samples must remain frozen during storage and shipment. 

Stability is 14 days at -20°C or at –70°C for up to 12 months.



Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.

Pediatric Specimen Requirements:

One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate. Specimens must be processed and frozen within 2 hours of specimen collection. 

Send 1 600 uL aliquot of platelet poor plasma, samples must remain frozen during storage and shipment. 

Stability is 14 days at -20°C or at –70°C for up to 12 months.

For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.

Reference Range:

40% to 130%

For children less than 6 months, see link to published reference ranges (Opens in a new window).

Comments:

This test aids in diagnosis of von Willebrand disease.

Von Willebrand disease is characterized by easy bruising or prolonged bleeding from mucosal surfaces due to quantitative (Type I) or qualitative (Type II) vWF deficiency. Both quantitative and qualitative (functional) assays are required for the diagnosis and appropriate therapeutic intervention. Because many patients with vWD have mild disease, repeated testing may be necessary to diagnose this disorder. Normal values do not exclude vWD. Female patients with vWD on oral contraceptives or who are pregnant may have normal values. Von Willebrand factor is also an acute-phase reactant and is elevated with stress or exercise.

Methodology: Turbidometric Enzymeimmunoassay.

This test was developed and its performance characteristics determined by OHSU.The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

The clinical significance of vWF activity levels between 0.3 to 0.5 U/mL is unclear and clinical correlation is required. See NHLBI von Willebrand Disease Expert Panel Guidelines:

https://www.nhlbi.nih.gov/health-pro/guidelines/current/von-willebrand-guidelines/full-report/1-intro.htm  (Opens in a new window)