This question was forwarded by an American Society for Clinical Laboratory Science Consumer Web Forum volunteer: Our hospital currently uses activated clotting time (ACT) results during heart catheterizations to monitor heparin dosage. The ACT is also used as a guide for pulling the sheath. The nurse confirms that the ACT is less than a certain value before removing the sheath. Would it be possible/advisable to use the partial thromboplastin time (PTT) result instead of ACT as a guide to pulling the sheath if the patient has been transferred to a room and the ACT device is not available for testing?
Hello, and thank you for your question. As you know, the cardiac catheterization staff monitor heparin using the ACT as the dosage of heparin used during a procedure exceeds the linearity of the PTT. The cardiologist reverses the heparin effect with protamine sulfate and runs the ACT to learn if the heparin has been fully neutralized. Once that has been accomplished, the PTT should provide acceptable results. I am attending the Thrombosis and Hemostasis Summit of North America in Chicago and had the opportunity to review this question with Dr. Larry Brace, who agrees that the PTT is acceptable provided the results are within the range of linearity. In the case of this questioner, this would be an efficient and accurate use of the PTT.