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Test Code RCF Ristocetin Cofactor

Laboratory Code

LAB335

Specimen Requirements

Submit only one of the following specimens


Specimen Type: Whole Blood
Container/Tube: 2 Light Blue Top (3.2% Sodium Citrate)
Volume: 2 × 2.7 mL (Tubes must be full)
Collection Instructions: Send whole blood specimens to laboratory immediately.


Specimen Type: Platelet Poor Plasma
Container/Tube: 2 Light Blue Top (3.2% Sodium Citrate)
Submission Container/Tube: Plastic Vial

Minimum Volume: 1.0 mL plasma
Collection Instructions:
1. Light blue top tube must be properly filled with whole blood.

2. Whole blood specimen should be double centrifuged and plasma separated from cells within 1 hr of collection.
3. Plasma should be separated into 2 aliquots with minimum volume of 1.0 mL each.
4. Freeze the aliquots in well-closed plastic tubes immediately.

Specimen Stability

Specimen Type Plasma
Ambient 4 hours
Refrigerate 4 hours
Frozen 14 days (preferred)

Methodology

Immunoturbidimetric Assay

Days and Times Performed

Friday, TAT 21 days

Specimen Condition

Haemolysis Gross reject
Icterus Gross reject
Lipaemia Gross reject
Others: Clotted or insufficient Reject

Reference Interval

Blood O-group 44 – 141 %
Blood group non-O 63 – 200%

Testing Laboratory

National University Hospital
Haematology, 67725320

Useful For

Aids in the diagnosis of von Willebrand’s Disease.

Service Code

12021

Alias

Ristocetin Cofactor Activity

RCF

Ricof

Ristocetin

vWF Activity

von WIllebrand’s Disease

vWD

Update

Last updated 21/03/2025