Intended use

Automated latex enhanced immunoassay for the quantitative determination of von Willebrand Factor Antigen (VWF:Ag) in human citrated plasma on IL Coagulation Systems.

Summary and principle

The diagnosis of von Willebrand disease (VWD), probably the most common congenital bleeding disorder, requires a number of special tests at the laboratory level.Among them, VWF:Ag determination is essential and must be performed on every patient to reach a proper diagnosis.

Depending upon these laboratory findings, VWD is classified into type 1 (the most frequent form being 70-80% of VWD), type 2 or type 3 (1 to 3% of VWD) groups.Type 1 shows a reduction of VWF although its structure and functionality is normal. In type 3, VWF is almost absent in plasma. In type 2 the quantity of VWF in plasma may be normal or slightly reduced but its molecular structure and its functionality is abnormal. Type 2 may be further characterized into subtypes by multimeric structure analysis of VWF.

Apart from the above described inherited VWD, acquired VWD due to autoantibodies or to various disease states resulting in low rates of VWF synthesis has been reported. On the other side, chronic or acute inflammatory diseases or processes involving damage of the vascular endothelium yield abnormally high concentrations of VWF.

The VWF:Ag kit is a latex particle enhanced immunoturbidimetric assay to quantify VWF:Ag in plasma. When a plasma containing VWF:Ag is mixed with the Latex Reagent and the Reaction Buffer included in the kit, the coated latex particles agglutinate. The degree of agglutination is directly proportional to the concentration of VWF:Ag in the sample and is determined by measuring the decrease of transmitted light caused by the aggregates.

Reagents -- Composition, Packaging, Storage and Stability

Latex Reagent (Cat. No. 0020002310): 2 vials x 3 mL of a suspension of polystyrene latex particles coated with a rabbit polyclonal antibody directed against VWF containing bovine serum albumin, buffer, stabilizer and preservative.

Reaction Buffer (Cat. No. 0020002320): 2 vials x 4 mL of HEPES buffer containing bovine serum albumin, stabilizers and preservative.

Unopened reagents are stable until the expiration date shown on the vial when stored at 2-8°C. Opened reagents are stable 3 months at 2-8°C in the original vial or 1 week at 15°C on the ACL® 8000/9000/10000, ACL Futura®/ACL Advance Systems and ACL TOPTM. Do not freeze.

For optimal stability remove reagents from the system and store them at 2-8°C in the original vial.

Additional reagents and control plasmas
The following are not supplied with the kit and must be purchased separately.

• Calibration plasma (Cat. No. 0020000000)
• Normal Control (Cat. No. 0020003120)
• Special Test Controls Levels 1 & 2 (Cat. No. 0008467600)
• Factor diluent (Cat. No. 0009757600)