What observation should be made when administering Heparin?

When administering Heparin, avoiding massaging the injection site is crucial due to the nature of the medication and how it is delivered into the body. Heparin is an anticoagulant, which means it works by inhibiting blood clotting. Massaging the injection site can enhance absorption and may increase the risk of localized bleeding or bruising, thus counteracting the intended therapeutic effects of the drug. To ensure patient safety and optimize the effectiveness of Heparin treatment, it is best to keep the injection site undisturbed after administration.

The other choices involve considerations that, while important in various contexts of patient care, do not directly pertain to the immediate administration technique of Heparin. Blood pressure checks are relevant for overall patient monitoring but are not specific to Heparin administration. Monitoring liver function is typically more pertinent to other medications or conditions, and while checking for allergic reactions is a general practice in medication administration, it is less applicable here as allergic reactions to Heparin are not routine and do not directly relate to the method of administration itself.