TXB2 is a stable, biologically inert metabolite formed from the non-enzymatic hydrolysis of TXA2, which has a half-life of about 30 seconds.[1] Urinary analysis of TXB2 accurately reflects intrarenal TXA2 synthesis, while measurement of 11-dehydro and 2,3-dinor thromboxane metabolites gives the best estimate of systemic TXA2 secretion.[2],[3],[4]
Reference:
[1]. Needleman, P., Moncada, S., Bunting, S., et al. Identification of an enzyme in platelet microsomes which generates thromboxane A2 from prostaglandin endoperoxides. Nature 261(5561), 558-560 (1976).
[2]. Patrono, C., Ciabattoni, G., Patrignani, P., et al. Evidence for a renal origin of urinary thromboxane B2 in health and disease. Adv. Prostaglandin Thromboxane Leukot. Res. 11, 493-498 (1983).
[3]. Lawson, J.A., Patrono, C., Ciabattoni, G., et al. Long-lived enzymatic metabolites of thromboxane B2 in the human circulation. Anal. Biochem. 155(1), 198-205 (1986).
[4]. Patrono, C., Ciabattoni, G., Pugliese, F., et al. Estimated rate of thromboxane secretion into the circulation of normal humans. J. Clin. Invest. 77(2), 590-594 (1986).