Regarding the collection of samples for blood culture, which of the following statements is WRONG?

RML 2023

Nursing Foundation

Medium

Appeared in: RML 2023

Explanation

The statement 'A serum-polymer test is done after disinfecting the skin' is factually incorrect.
There is no standard, recognized procedure known as a 'serum-polymer test' in the context of collecting blood for cultures.
Because the question asks to identify the WRONG statement, this fabricated procedure is the correct answer.

Option A: This is a correct statement. Collecting samples from peripheral veins is the standard, recommended practice to minimize the risk of contamination from indwelling lines.
Option B: This is a correct statement. A critical step in aseptic technique for blood cultures is cleaning the site with an antiseptic for at least 30 seconds to eliminate skin flora.
Option D: This is a correct statement. To maximize the diagnostic yield, blood should be drawn at the antibiotic's trough level (just before the next dose), when its concentration is lowest in the bloodstream.

Clinical Relevance

Nursing practice connection: Knowing Aseptic technique and best practices for blood culture sample collection helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
A contaminated blood culture can lead to a false-positive result, which may cause unnecessary antibiotic administration, contribute to antibiotic resistance, prolong hospital stays, and increase healthcare costs.
Strict adherence to the collection protocol is a critical nursing responsibility to ensure diagnostic accuracy and guide appropriate patient treatment.
What if? If a catheter-related bloodstream infection (CRBSI) is suspected, blood should be drawn simultaneously from both a peripheral vein and the catheter hub. A differential time to positivity (where the catheter sample grows organisms at least 2 hours before the peripheral sample) helps confirm the catheter as the source of infection.

How to Approach the Question

First, identify the core subject of the question, which is the procedure for blood culture collection.
Note the negative framing of the question with the keyword 'WRONG'. This means you are searching for the statement that is factually incorrect or does not follow standard protocol.
Systematically evaluate each option against your knowledge of standard nursing procedures.
Option A (peripheral veins) is the standard recommendation. Option B (30-second cleaning) is a key part of asepsis. Option D (timing before antibiotics) is correct for obtaining a trough level.
Option C introduces an unfamiliar term, 'serum-polymer test'. In a 'which is wrong' question, a fabricated or irrelevant statement is a very strong candidate for the correct answer.
Conclude that the unfamiliar and non-standard procedure described in Option C is the incorrect statement and therefore the answer to the question.

Concept Tested & Keywords

Concept Tested: Aseptic technique and best practices for blood culture sample collection.
Stem keywords: blood culture, sample collection
Lead-in keywords: WRONG
Negative lead-in flag: The question asks to identify the WRONG statement.

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