What should be the strength of hypochlorite solution for disinfection?

Appeared in: NHM MP Staff Nurse-2019

Explanation

A 0.1% sodium hypochlorite solution is the standard recommended strength for the routine disinfection of surfaces in healthcare settings.
This concentration provides approximately 1000 parts per million (ppm) of available chlorine, which is effective against a broad spectrum of microorganisms, including bacteria, viruses, and fungi.
It effectively balances antimicrobial efficacy with safety for regular use on environmental surfaces and non-critical medical equipment.

Option A: A 0.01% solution is generally considered too weak for effective disinfection in a clinical setting where pathogenic microorganisms are a concern.
Option C: A 0.005% solution is an extremely low concentration and is ineffective for any standard disinfection protocol in healthcare.
Option D: While a 0.05% solution (approx. 500 ppm) has some disinfectant properties, it is typically recommended for general housekeeping or cleaning of non-critical surfaces, not for the standard disinfection of patient care areas.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Infection Control: Chemical Disinfection as background academic context rather than a clinical decision trigger.
Correct dilution of disinfectants is a critical nursing responsibility to prevent healthcare-associated infections (HAIs).
Using a solution that is too weak fails to kill pathogens, while a solution that is too strong can damage surfaces and cause respiratory or skin irritation to staff and patients.
What if? - If the task was to disinfect a surface contaminated with a blood spill, the correct concentration would be higher, typically 0.5% (for small spills) to 1.0% (for large spills), not 0.1%.

How to Approach the Question

This is a factual recall question about infection control standards.
Identify the core of the question: the standard strength of hypochlorite for general disinfection in a clinical setting.
Recall the standard concentrations for different disinfection tasks. The most common strength for routine surface disinfection is 0.1% (1000 ppm).
Compare the given options to this standard.
Eliminate other options by identifying their uses: 0.05% is for lower-level cleaning, while 0.01% and 0.005% are too weak for clinical use. Higher concentrations (e.g., 0.5%) are reserved for specific situations like blood spills.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) p. 128-130

Practise the full NHM MP Staff Nurse-2019

Attempt every question from this paper in a timed mock, then review the full solution for each one.