Method and reagent for monitoring blood levels of antiplantelet compounds

A method for determining blood concentration of an antiplatelet compound in a subject being treated with the antiplatelet compound and heparin, which comprises the steps of:

• (a) taking a blood sample from the said subject;
• (b) treating the subject's blood sample with antibody combining site-containing molecules that specifically bind to said antiplatelet compound to form antibody-treated blood;
• (c) calculating activated clotting time of the subject's antibody-treated blood;
• and
• (d) comparing the calculated activated clotting time of the antibody-treated blood to a standardized concentration curve from normal untreated blood thereby determining the amount of the antiplatelet compound in the blood of the subject.

A method for determining blood concentration of an antiplatelet compound in a subject being treated with the antiplatelet compound, which comprises the steps of:

• (a) taking a blood sample from the subject;
• (b) separating the sample into at least two portions and adding antibody combining site-containing molecules that specifically bind to said antiplatelet compound to one of the portions forming antibody-treated blood;
• (c) measuring the activated clotting time of at least one portion of the blood from (b) that is not treated with said antibody combining site-containing molecules;
• (d) measuring the activated clotting time of at least one portion of the blood sample from (b) that is treated with said antibody combining site-containing molecules;
• (e) calculating activated clotting time from the measurements of (c) and (d);
• and
• (f) comparing the calculated activated clotting time from (e) to a standardized concentration curve from normal untreated blood thereby determining the concentration of the antiplatelet compound in the subject.