Biological and medical glossaries are full of ambiguous language and similar terminology. One of these common points of confusion is the difference between aseptic technique vs. sterile technique.

Contrary to popular belief, they aren’t quite identical terms. Both work to prevent the spread of disease, but they do so in different ways and aren’t always useful in the same environments.

In this guide, we’ll go over when to use aseptic techniques, when to use sterile techniques, and the differences between each of them. Keep reading for a summary of what you need to know to avoid biocontamination.

The Principles of Sterile Technique

When something is sterile, it’s completely free of any live microscopic organisms. This includes the standard bacteria, viruses, fungi, and protists. It also extends to more resistant bacterial spores.

Sterile technique involves the sanitization of surfaces and implements. The most common ways to achieve sterility include:

• high heat
• high pressure
• steam
• chemical sanitization
• irradiation
• filtration

Heat, pressure, and steam are the most common sanitization methods. All three combine in an autoclave, a machine that’s used to kill microbes on medical or scientific instruments.

Professional piercers also often use autoclaves to sterilize their equipment and jewelry. This lowers the risk of infection after a piercing.

True sterile fields are very difficult to maintain outside of an autoclave, laboratory hood, or enclosed package. As soon as an item is exposed to unfiltered air, for example, it’s no longer sterile. When you’re working with things that can’t be completely sterilized, you’ll need to use aseptic technique instead.

The Principles of Aseptic Technique

The term aseptic refers to something an item or environment that’s free of disease or disease-causing microbes.

Aseptic techniques are preventative techniques. Their goal is to take sterile items and surfaces and keep them from being contaminated with harmful pathogens while in use.

Aseptic technique can’t guarantee an environment that’s free of all microbes. When followed correctly, though, it should be free of all harmful microbes.

The main principles of aseptic technique include:

• assessing the potential biocontamination risks
• decontaminating tools, surfaces, and key parts
• protecting yourself and others from spreading pathogens
• wearing personal protective equipment (PPE)
• creating and working within aseptic fields (germ-free spaces)
• using non-touch techniques whenever possible
• avoiding cross-contamination

The specifics of aseptic technique will vary depending on the environment. Regardless of its application, maintaining asepsis requires a rigorous and detailed approach. It’s much more complex than sterilization.

How to Maintain an Aseptic Environment

While sterilization is often a single-step process, aseptic technique is a complicated series of events. To create a germ-free environment, workers must adhere to the following procedures:

• only using sterilized equipment
• disposing of used equipment in proper biosafety containers
• only allowing necessary personnel to enter the aseptic field and minimizing traffic through the room
• frequent or continuous air filtration
• practicing excellent hand hygiene
• wearing gloves, masks, eye shields, gowns, hair and boot covers, or other PPE
• keeping doors closed as much as possible during the procedure or event

These are basic protocols that apply to every aseptic environment. Your workplace may ask you to adhere to even stricter standards than the ones listed here.

When You Should Use Aseptic Technique vs. Sterile Technique

In real-life practice, there’s quite a bit of overlap between aseptic and sterile techniques. Even so, there are some things—like the human body—that you can’t make sterile. If you tried to sterilize a wound with high heat, for example, you could cause serious burns.

To better understand, let’s dive a bit deeper into when each method is most useful.

When to Use Sterile Technique

Sterile techniques are brute-force attacks against microorganisms of all types. They’re best for small-scale operations, like sanitizing tools. They’re also used in industrial facilities like food processing plants.

Some of the most common applications of sterile technique include:

• sterilization of canned foods to reduce Clostridium botulinum spores and mold contamination
• preserving milk
• sterilization of jarred and bottled foods to increase shelf life
• sterile laboratory hoods and rooms for biological research (such as with germ-free mouse colonies)
• disinfecting surgical implements like scalpels, gauze, and forceps
• sanitizing jewelry before new piercings

Most of the time, sterile technique is only part of the larger process. People working with sterile objects must use aseptic technique to avoid contamination during use.

When Aseptic Technique Is Appropriate

Asepsis is used most often in the fields of medicine and research. It’s also useful in the manufacturing of food and drugs.

Some situations that need aseptic technique include:

• food packaging
• manufacturing and packaging medications
• performing surgery or handling surgical implements
• delivering a baby via vaginal birth or cesarean section
• performing dialysis
• giving a blood transfusion
• inserting a catheter, IV, arterial line, or chest tube
• dressing burns or caring for open wounds
• performing a biopsy
• plating bacterial cultures
• working with dangerous pathogens in a microbiology lab

As mentioned before, aseptic technique is useful in most circumstances where you can’t get rid of all microbes, but need to avoid introducing harmful ones.

Educate Yourself About Reducing Pathogen Spread

Whether you work in a lab, a factory, or an operating theater, one thing’s for sure. Knowing the difference between aseptic technique vs. sterile technique is the first step in preventing the spread of disease. The more you know about them, the easier it is to identify when to use each one and how best to avoid contamination.

This guide covers the basics, but there’s a lot more to sterile and aseptic technique than we talked about here. For more in-depth information, make sure to check back with our site for other articles like this one.