A new method of measuring heparin levels in whole blood by protamine titration using a heparin-responsive electrochemical sensor

Objective: To determine the ability of a new electrochemical sensor to determine heparin levels in whole blood and to correlate the heparin levels as determined by this heparin-responsive sensor (HRS) with heparin levels as determined by the Hepcon assay system (Medtronic Hemotec, Parker, CO). Design: Methods comparison study. Setting: A large academic medical center. Interventions: The heparin levels of 162 samples from 24 patients undergoing cardiopulmonary bypass were determined by the HRS system and by the Hepcon system. In 21 samples, heparin levels as measured by anti-Xa activity were determined as well. Measurements and Main Results; HRS-determined values correlated highly with Hepcon-determined values (r = 0.942) and with anti-Xa determined values (r = 0.905). Bias +/- precision comparing the HRS and Hepcon methods was 0.211 +/- 0.478 U/mL. Conclusions: HRS determined that whole blood heparin levels correlate well with Hepcon-determined levels. These limited results indicate that further development and testing of this new technology are warranted. Copyright (C) 1996 by W.B. Saunders Company