11-Dehydrothromboxane B2 (11dhTxB2 or 11-dehydro-TxB2) is a stable metabolite of Thromboxane A2 (TxA2). TxA2 is a prothrombotic agent capable of promoting the activation and subsequent aggregation of platelets nearby. It is derived from Arachidonic Acid in the COX pathway and is involved in maintaining hemostasis & preventing cardiovascular diseases. TxA2 has a very short half-life and is quickly hydrolysed to thromboxane B2 (TxB2), which further metabolises to 11dhTxB2. 11dhTxB2 has a stable half-life and is excreted in the urine. It is unaffected by the ex vivo platelet activation and other pre-analytical variables. Urinary 11dhTxB2 can directly reflect the platelet production of TxA2 and represents a good and reliable biomarker for platelet activity. Additionally, Aspirin can irreversibly inhibit the platelet COX-1 activity thereby resulting in the inhibition of TxA2 production and thromboxane-mediated platelet activation. Thus, urine levels of 11dhTxB2 reflect COX-1 inhibition and can be used to monitor responses to Aspirin therapy. BioVision’s 11-Dehydrothromboxane B2 ELISA Kit can quickly and reliably determine a broad range of 11dhTxB2 concentrations in human urine samples. It is a competitive ELISA, based on the competition between the free 11dhTxB2 and 11dhTxB2-Acethylcholinesterase (AChE) conjugate for a constant amount of 11dhTxB2 monoclonal antibody binding sites. Thus, in the presence of an AChE substrate, the absorbance of the released product is inversely proportional to the amount of 11dhTxB2 in samples. The kit can detect as low as 15.6 pg/ml of 11dhTxB2 in 60 minutes.