Sensitivity and reaction is tested by administering the drug?

PGIMS Rohtak NO - 2017

Nursing Foundation

Medium

Appeared in: PGIMS Rohtak NO - 2017

Explanation

The intradermal (ID) route is the standard for sensitivity testing because the drug is injected into the dermis.
The dermis contains a high concentration of mast cells, which, upon exposure to an allergen, release histamine and other mediators, causing a visible wheal-and-flare reaction.
This route ensures very slow absorption into the systemic circulation, which localizes the reaction and significantly reduces the risk of a life-threatening systemic response.
It is the method used for allergy testing (e.g., penicillin) and for the Mantoux tuberculin skin test.

Option B: The intramuscular (IM) route leads to rapid absorption from the muscle tissue into the bloodstream. This increases the risk of a systemic allergic reaction, and any local reaction would be deep within the muscle, making it impossible to observe.
Option C: The intravenous (IV) route is the most dangerous for sensitivity testing. It delivers the drug directly into the systemic circulation, which can trigger an immediate, severe, and potentially fatal anaphylactic reaction.
Option D: The subcutaneous (SC) route has slower absorption than IM or IV, but it is still faster and less localized than the ID route. A reaction in the subcutaneous tissue is less pronounced and harder to interpret accurately compared to the distinct wheal formed in the dermis.

Clinical Relevance

Nursing practice connection: Knowing Parenteral drug administration routes for sensitivity testing helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Patient safety is paramount. Using the correct intradermal technique for sensitivity testing minimizes the risk of anaphylaxis. Using an incorrect route like IV could be fatal.
A crucial nursing responsibility when performing any sensitivity test is to have an emergency anaphylaxis kit readily available. This includes epinephrine, antihistamines, corticosteroids, and airway support equipment.
What if? If a patient develops wheezing, facial swelling, and a drop in blood pressure minutes after an ID test, the nurse must recognize this as anaphylaxis. The immediate priority is to call for help, administer epinephrine as per protocol, maintain the airway, and monitor vital signs closely.

How to Approach the Question

First, identify the key purpose of the action described in the question: 'to test for sensitivity and reaction'.
Recall that the goal of a sensitivity test is to elicit a localized, observable reaction while minimizing the risk of a systemic, body-wide response.
Evaluate the four administration routes based on their absorption speed and location of drug deposit.
Intravenous (IV) is the fastest and most systemic, making it the most dangerous and incorrect choice.
Intramuscular (IM) is also fast and systemic, and the reaction site is too deep to observe.
Subcutaneous (SC) is slower but still allows for more systemic absorption than desired, and the reaction is less clear.

Concept Tested & Keywords

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