The biologic half-life of heparin

Half-lives (t1/2s) varying from 23 min to 2.48 hr have been reported for heparin. It is shown that much of the discrepancy between authors can be attributed to methods used to analyze data. It is suggested that three terms should be carefully used, the t1/2 of bioassayed heparin concentration, the t1/2 of the extension of the clotting time, and the t 1/2 of the clotting time to differentiate among the various methods of analyzing the raw data.