Your patient is started on a Heparin drip. You administer a bolus of Heparin and start the drip per protocol as ordered by the physician. What will be your next important nursing action?

Choice A rationale Prothrombin time (PT) is the primary laboratory test used to monitor warfarin (Coumadin) therapy, not unfractionated heparin (UFH). Furthermore, laboratory monitoring for UFH is typically required sooner than 6 hours after initiating the drip, usually within 4 to 6 hours after the bolus and initiation, to evaluate the therapeutic effect. Choice B rationale The International Normalized Ratio (INR) is a standardized way to report the PT result, and it is also used primarily to monitor warfarin effectiveness and not UFH therapy. Although it is a standard time frame, it is the wrong test for heparin. The correct test for monitoring UFH is the aPTT, not the INR. Choice C rationale Troponin is a cardiac enzyme released into the blood when the heart muscle (myocardium) has been injured, often due to a myocardial infarction. While the patient may have been started on heparin for an acute coronary syndrome, a Troponin level is a diagnostic test for cardiac injury and is not used to monitor the therapeutic effect of heparin anticoagulation. Choice D rationale The Activated Partial Thromboplastin Time (aPTT) is the standard and correct laboratory test used to monitor the therapeutic efficacy of unfractionated heparin (UFH) infusion. The aPTT should be collected approximately 6 hours after the bolus and initiation of the drip, or after any rate change, to ensure the patient's value is within the desired therapeutic range (typically 1.5 to 2.5 times the control or baseline value).