Method of assaying a blood sample for prothrombin
AssigneeEvanston Northwestern Healthcare Research Institute
InventorStuart E. Lind
Life of this patent
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Abstract
An improved method of assaying undiluted whole blood or undiluted plasma for prothrombin is disclosed. The improved method utilizes carinactivase-1 and calcium ions, and eliminates the need for a prothrombin-deficient plasma as a reference plasma.
Claims19
A method of assaying an undiluted whole blood or undiluted blood plasma sample for native prothrombin comprising:
- (a) contacting the sample with a reagent composition which forms a detectable response, said reagent composition comprising:
- (i) about 10 nM to about 0.1 mM of carinactivase-1,
- (ii) about 1 to about 30 mM calcium ions,
- (iii) about 10 to about 600 mM of a buffer to provide a pH of about 7 to about 8;
- and
- (iv) about 0.1 to about 5 mM of an indicator;
- (b) measuring an intensity of the detectable response;
- and
- (c) correlating the intensity of the detectable response to a prothrombin concentration of the sample,
- wherein the carinactivase-1 is free of ecarin and the reagent composition interacts with native prothrombin and is inert with respect to descarboxyprothrobin.
A method of assaying an undiluted whole blood or undiluted blood plasma sample for prothrombin comprising:
- (a) contacting the sample or the undiluted blood plasma with a reagent composition comprising:
- (i) about 10 nm to about 0.1 mM of carinactivase-1,
- (ii) about 1 to about 30 mM calcium ions,
- (iii) about 100 mM to about 600 mM of a buffer to provide a pH of about 7 to about 8, wherein the carinactivase-1 is free of ecarin and the reagent composition interacts with native prothrombin and is inert with respect to descarboxprothrombin;
- and
- (b) measuring a clotting time of the sample;
- and
- (c) correlating the clotting time to a prothrombin concentration of the sample.
A test strip for assaying an undiluted whole blood sample or an undiluted blood plasma sample for native prothrombin comprising:
- (a) a support strip, and
- (b) a test pad secured to the support strip, said test pad comprising:
- (i) a carrier matrix, and
- (ii) a reagent composition incorporated into the carrier matrix, said composition comprising:
- (A) about 10 nM to about 0.1 mM of carinactivase-1, wherein the carinactivase-1 is free of ecarin,
- (B) about 1 to about 30 mM calcium ions,
- (C) about 100 mM to about 600 mM of a buffer to provide a pH of about 7 to about 8;
- and
- (D) about 0.1 to about 5 mM of an indicator,
- wherein the reagent composition intracts with native prothrombin and is inert with respect to descarboxyprothrombin.
A method of assaying for a native prothrombin concentration of undiluted whole blood or undiluted plasma comprising:
- (a) contacting the undiluted whole blood or undiluted plasma with an analyte detection device comprising a test pad containing a reagent composition comprising:
- (i) about 10 nM to about 0.1 mM of carinactivase-1,
- (ii) about 1 to about 30 mM calcium ions,
- (iii) about 100 mM to about 600 mM of a buffer to provide a pH of about 7 to about 8, and
- (iv) about 0.1 to about 5 mM of an indicator, wherein the carinactivase-1 is free of ecarin and the reagent, composition interacts with native prothrombin and is inert with respect to descarboxyprothrombin;
- and
- (b) examining the analyte detection device for a detectable response to the native prothrombin concentration of the undiluted whole blood or undiluted plasma.
Dependencies are inferred from the claim text.