Category
Coagulation
SubCategory
Bleeding/ bleeding risk assessment
Abbreviations
VWF AG
Synonyms/Aliases
VWF antigen, factor viii cofactor antigen
Test
Individual Test
Results
results ready aftER 7-10 working Days
Method
Clotting
Temp
Transportation temperature need to be Frozen
Setup
Setup is Conducted Once a week
Pre-analytic Considerations
.
Component Parameters
N/A
Sample Requirements
Citrated whole blood/ plasma
Test Ordering Instructions
fill out test request form fully & legibly.
Test Considerations
fill out test request form fully & legibly. fasting sample, sample filled up to the mark
Patient Preparations
Fasting , preferably patient should not be on anticoagulants 2 weeks prior to the test
Sample Types
citrated platelet poor plasma (frozen)
Container / Presavative
citrate (light blue top) vacutainer during sample collection.
Sample Volume
During sample collection, fill up to the mark on the tube (do not "add up" samples collected in other tubes to reach the required volume). submit 2ml platelet poor (double centrifuged) frozen citrated plasma in a separation vial. the aliquot label should identify the sample type as citrated plasma.
Rejection Criteria
labeling issue (unlabeled/ mislabeled); missing request form; mismatch between request form & sample details; missing age/ gender; wrong sample type; insufficient sample; hemolyzed samples; clotted samples; incorrect temperature handling.
Reference intervals
Appropriate values are provided on the report
Clinical utility
Diagnose von willebrand factor deficiency
Test Limitations /Confounders
VWF levels can be elevated in many conditions
Other Instructions
To prepare Platelet poor Plasma, Double centrifuge sample immediately after collection i.e. centrifuge, transfer pPasma, centrifuge plasma a second time & transfer the supernatant which should now be platelet poor. freeze immediately.