DiaPharma Group, Inc.

For in vitro diagnostic use

Coamatic® Plasmin Inhibitor is a novel, automated method, which provides the means for conducting a more specific analysis of plasmin inhibitor activity in plasma [Billing-Clason S et al. Fibrinolysis 10, suppl 2, 165-167 (1996)]. The assay combines the use of short incubation time and low plasmin concentration with the highly selective chromogenic plasmin substrate S-2403. In addition, the method has been made insensitive to alpha2-Macroglobulin by adding methylamine in the buffer. These improvements ensure a high specificity and a steep standard curve throughout the whole measuring range 0-130%. Assay has linear and steep standard curve, low CV within and between test series, and validated and documented for a wide range of instruments.

Intended use of the kit

For the quantitative determination of plasmin inhibitor (alpha2-antiplasmin) activity in human citrated plasma using microplate, test tube and automated methods.

Background and summary

Plasmin inhibitor, the major fast-acting inhibitor of the fibrinolytic system, also known as alpha2-antiplasmin, is an important regulator of the fibrinolytic system.Congenital deficiences are characterized by bleeding occuring some hours after the initial injury. Clotting and wound healing are usually normal, but the hemostatic plug is defective and breaks down prematurely. As a result of liver diseases and DIC, decreased levels of plasmin inhibitor can be observed.Increased levels have been reported during postoperative episodes.

Measurement principle

Incubation of diluted plasma with an excess of plasmin results in a rapid complex formation between functional plasmin inhibitor present in the plasma and plasmin. The inhibited plasmin activity is proportional to the amount of plasmin inhibitor. The remaining amount of plasmin hydrolyzes the chromogenic substrate S-2403, thus liberating the chromophoric group, pNA. The color is then read photometrically at 405 nm.

Assay Principle

Example of Standard Curve

Reagents -- Composition, Packaging, Storage and Stability

S-2403 8.4 mg 1 vial. Chromogenic substrate (pyroGlu-Phe-Lys-pNA) lyophilized with mannitol (bulking agent). Stability after reconstitution: 6 months at 2-8°C in the original vial.

Plasmin Solvent 10 mL 1 vial. Sterile solution of glycerol and 2 mmol/L HCl. Stability when opened: until the expiry date printed on the label.

Buffer, stock solution 10 mL 2 vials. Characteristics of diluted buffer (1:10): Tris 0.05 mol/L, pH 7.4 with 0.15 mol/L methylamine and 0.01% Tween 80. Stability when opened: until the expiry date printed on the label. Stability after dilution 1:10 with sterile water (see REAGENTS 5) (working buffer): 2 months at 2-8°C.

Plasmin 8 nkat 1 vial. Lyophilized human plasmin. Stability after reconstitution in Plasmin Solvent (plasmin stock solution, 2 nkat/mL): 1 month at 2-8°C. Stability after dilution of plasmin stock solution with working buffer (working plasmin solution): 3 days at 2-8°C.

The sealed reagents are stable at 2-8°C until the expiry date printed on the label. Avoid contamination by microorganisms in the reagents.

WARNING: Do not use reagents beyond the expiry date printed on the package label. Discard if the substrate solution appears yellow.

Number of determinations:

• 50 (test tube)
• 200 (microplate)
• 125-200 (automated)