Which test result should a nurse review to determine if the antibiotic prescribed for the patient will be eff… - NCL (MP) Nursing Officer - 2019

NCL (MP) Nursing Officer - 2019

Pharmacology

Easy

Appeared in: NCL (MP) Nursing Officer - 2019

Explanation

A sensitivity test is specifically designed to determine the effectiveness of various antibiotics against a specific microorganism.
This test is the second part of a 'Culture and Sensitivity' (C&S) analysis, which is the gold standard for guiding antibiotic therapy.
The results are reported as Susceptible (S), Intermediate (I), or Resistant (R), allowing the clinician to select an antibiotic labeled 'S' for the best clinical outcome.
Choosing an antibiotic based on sensitivity results ensures targeted therapy, which improves patient outcomes and helps prevent the development of antibiotic resistance.

Option A: A serologic test detects the body's immune response (antibodies) or the presence of microbial antigens. It is used for diagnosis, not for determining antibiotic effectiveness.
Option C: Serum osmolality measures the concentration of solutes in the blood, which reflects the body's fluid and electrolyte status. It has no role in guiding antibiotic selection.
Option D: The sedimentation rate (ESR) is a non-specific marker of inflammation. While it can be elevated during an infection, it does not identify the causative organism or its susceptibility to antibiotics.

Clinical Relevance

Nursing practice connection: Use the key finding related to Guiding antibiotic therapy using laboratory results to guide bedside assessment, documentation, and the next nursing action.
A primary nursing responsibility is to collect culture specimens (e.g., blood, urine, sputum) before the first dose of an antibiotic is administered. This prevents the antibiotic from altering the test results, ensuring an accurate identification and sensitivity profile.
Reviewing C&S results is a key component of antimicrobial stewardship. By advocating for the most targeted (narrow-spectrum) antibiotic, nurses help reduce the risk of superinfections (like C. difficile) and combat the global crisis of antibiotic resistance.
What if? The patient is critically ill with suspected sepsis and cannot wait 48-72 hours for C&S results? The nurse should still obtain cultures immediately, then administer prescribed broad-spectrum antibiotics. Once the sensitivity results are available, the therapy can be de-escalated to a more targeted, narrow-spectrum antibiotic.

How to Approach the Question

First, identify the core of the question: it asks for the specific test that proves an antibiotic will be effective against a particular infection.
Next, analyze the function of each test listed in the options.
Consider 'Serologic test'. This tests for antibodies/antigens, which is about diagnosis, not treatment effectiveness. Eliminate this option.
Consider 'Serum osmolality'. This relates to fluid balance, not infection. Eliminate this option.
Consider 'Sedimentation rate'. This is a general marker for inflammation, not specific enough to guide antibiotic choice. Eliminate this option.
Finally, consider 'Sensitivity test'. The word 'sensitive' in this context directly relates to whether a microbe is susceptible to an antibiotic. This directly answers the question.

Concept Tested & Keywords

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E6 Microbiology Essentials Sastry 4e Part 1 p. 59-61

E6 Pharmacology Nursing Lilley 11e Part 2 p. 293-295

E6 Pathology-Vandana Puri & Kavita Gaur Textbook of Pathology and Genetics p. 454-456