Plasminogen activity

Plasminogen in test plasma is incubated with an excess of the exogenous plasminogen-activator isolated from haemolytic streptococcal bacteria, streptokinase, to form plasminogen-streptokinase complexes. The concentration of this complex is determined in a kinetic test by its action on a chromogenic substrate and subsequent release of a peptide and the coloured product p-nitroaniline (pNA). The increase in absorbance at 405nm produced by pNA release is directly proportional to plasminogen concentration.
Clinical details: 
Plasminogen is the zymogen precursor of the enzyme plasmin, which functions to degrade fibrin clots once bleeding has been arrested and wound healing has occurred. Deficiency of plasminogen, which can be quantitative or qualitative, can theoretically result in persistence and growth of clots and increase the risk of venous thromboembolic disease. Current opinion is that isolated plasminogen deficiency may not itself be a hypercoagulable condition although it may contribute if other risk factors are present.

Another crucial physiological role for plasminogen is as an integral component of wound healing. Patients with plasminogen deficiency have a marked reduction in wound healing ability, which is most pronounced in mucous membranes such as the conjuctiva. This leads to development of pseudo membranes on mucosal surfaces, and ultimately, organ damage. The most common presentation is ligneous conjuctivitis, other affected areas can be mouth, larynx, vocal cords, ear, tracheobronchial tree and female genitourinary tract.
Reference range: 

75 - 150

Sample type and Volume required: 
External requests: Citrated platelet poor plasma
450µL x 1 aliquot
Internal requests: please refer to EPR label
Turnaround time: 
7 - 10 days
Special sample instructions: 

The sample should be analysed or manipulated & stored in the laboratory within 4 hours of venepuncture. Please ensure sample tubes are filled exactly to the fill-line as underfilling creates a dilution error and leads to inaccurate results.

Diagnostic Haemostasis and Thrombosis Department
020 7188 2797
St Thomas' Hospital
North Wing - 4th and 5th Floors
Westminster Bridge Road
London SE1 7EH

Laboratory opening times
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 09/03/2017