| 摘要 |
<p>Method of determining the heparin content, which method comprises the following steps: (a) adding a known amount of thrombin (FIIa) or activated coagulation factor X (FXa) to a mixture which comprises a known concentration of chromogenic substrate (S), a known concentration of antithrombin (AT) and a sample having an unknown heparin concentration, the amount of FIIa or FXa being chosen such that at most 20 %, preferably at most 10 %, of the S present is reacted during the period which the AT needs to deactivate all the FIIa or FXa present, (b) allowing the reactions which occur to proceed and determining the final concentration of the reacted chromogenic substrate ([pNA]final) after completion of the reactions, (c) using the [pNA]final found to determine the rate constant (kdec) of the reaction of FIIa or FXa with AT, and (d) determining the heparin concentration in the sample using the value of kdec thus found from a predetermined calibration curve of kdec against heparin concentration.</p> |
