Regarding collection of samples for blood culture. Which of the following statements is WRONG?

RML Lucknow - 2021

Fundamental of Nursing

Medium

Appeared in: RML Lucknow - 2021

Explanation

The statement that blood should be collected only from peripheral veins is incorrect.
While peripheral venipuncture is the preferred method to minimize the risk of contamination from colonized central lines, it is not the only method.
Blood cultures are frequently drawn from central venous catheters (CVCs), especially when investigating a potential catheter-related bloodstream infection (CRBSI).
In cases of suspected CRBSI, paired cultures are drawn simultaneously from both a peripheral vein and the CVC. A faster growth time in the CVC sample suggests the catheter is the source of infection.

Option B: This is a correct statement. Scrubbing the venipuncture site with an appropriate antiseptic solution for at least 30 seconds is a critical step to decontaminate the skin and prevent the introduction of skin flora into the blood sample.
Option C: This is a correct statement. Re-palpating the vein after the skin has been disinfected reintroduces microorganisms onto the sterile site, significantly increasing the risk of contamination. This practice must be avoided.
Option D: This is a correct statement. For patients already receiving antibiotics, the sample should be collected just before the next dose is due. This is the 'trough' level, when the concentration of the antibiotic in the blood is at its lowest, thereby increasing the chance of recovering viable bacteria in the culture.

Clinical Relevance

Nursing practice connection: Knowing The core concept is the adherence to aseptic technique and established best practices during the collection of blood samples for culture to ensure accurate microbiological diagnosis and prevent contamination helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Preventing contamination of blood cultures is a critical nursing responsibility. A contaminated sample (a false positive) can lead to inappropriate antibiotic administration, prolonged hospital stays, and increased healthcare costs.
Strict adherence to aseptic technique directly impacts patient outcomes by ensuring that treatment is based on accurate diagnostic results.
What if? If a patient has no peripheral venous access and a blood culture is needed, a sample may be drawn from a central line. However, the nurse must document the collection site clearly, as this information is crucial for the laboratory and clinical team to interpret the results correctly, especially in the context of a potential line infection.

How to Approach the Question

First, identify the negative framing of the question, which asks for the 'WRONG' statement. This means you are looking for the option that does not represent a best practice.
Evaluate each statement based on your knowledge of standard infection control and specimen collection procedures.
Pay close attention to absolute words like 'only' or 'always'. These words often make a statement too restrictive and therefore incorrect.
Analyze the statement 'Blood should be collected only from peripheral veins'. Consider clinical situations, such as suspected central line infections, where this rule would not apply.
Confirm that the other three options represent established, evidence-based practices for blood culture collection (e.g., 30-second scrub, no re-palpation, timing with antibiotics).

Concept Tested & Keywords

Concept Tested: The core concept is the adherence to aseptic technique and established best practices during the collection of blood samples for culture to ensure accurate microbiological diagnosis and prevent contamination.
Stem keywords: blood culture, collection of samples, procedure
Lead-in keywords: WRONG
Negative lead-in flag: The question asks for the WRONG statement, meaning three of the options are correct practices.

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