Luer Slip Syringe vs. Luer Lock Syringe

Uses of syringes and needles have become diverse over time.

In the light of their changing needs, the designs and models of syringes and needles have been modified and diversified.

Today, there is a wide variety of these instruments available and are in use in medical fields and laboratories.

Among these are the Luer Slip and the Luer Lock syringes.

There are two key points to focus on when deciding to get either a Luer Slip or a Luer Lock syringe:

• The main difference between the two types of syringes.
• The purpose of purchase.

Once these two factors are decided, you can buy the perfect syringe you need.

This article will shed light on both these topics to give you a vivid understanding of these two syringe types and help you in making the correct decision according to your need.

Introduction to Luer Fitting

Let’s first take a look at what Luer is.

The Luer fitting can be best described as a system used as a standard for tapered tip when it comes to fluid fittings of a small scale such as in syringes.

The purpose of these fittings is to ensure that the connection between any two specific parts is leak-proof.

Syringes being a very common instrument in use in medical tasks and laboratory works are a common host of these connections.

The part of the syringe where the blade locks to the body of the syringe comes in a variety of designs.

Similarly, there are needles of various types for the variety of tips available as well.

Based on the different types of professional work at hand, there are multiple combinations of tips and needles available.

For instance, the hypodermic needles are used with syringes when a liquid has to be injected or removed from the body.

In these situations, the chances of air getting into the blood vessel can be quite hazardous.

In some cases, the syringes need to be reused such as by diabetic patients. Even though the same person is using the syringe in this case, still, the bacteria from the skin can reach the bloodstream and cause problems.

In a medical setup, only the practice of one-time use of such disposable equipment is promoted. Single-use equipment, like syringes and needles, is an effective player in the reduction of risks associated with cross-contamination.

Syringes are known to be the most common instruments to use Luer fitting system. In this system, the needle either tightly fits on the top or screws into it.

Based on these types of connections the syringes are classified into two categories: locking syringes and slipping syringes.

Difference between Luer Slip Syringe and Luer Lock Syringe:

The image below shows these two types of syringes. On the left is a sterile 2.5 ml Luer Slip Tip. On the right is a sterile 3 ml Luer Lock Tip.

Difference in Appearance

The Luer Slip syringes have a smooth spigot and there is complete absence of any type of collar.	The Luer Lock syringes on the other hand have an internal thread and a collar as seen in the image below.

Difference in Fitting Mechanism

The Luer Slip Tip comes with a friction-fit connection. The syringe tip is ‘slipped’ or pushed into the needle hub, resulting in a secure connection as shown in the image below.	With the Luer Lock Tip the hypodermic needle is screwed into the tip by rotating it clockwise and ‘locked’ in place. This connection results in acquiring a securely tight bond between the two components.

The term ‘male Luer fitting’ is used for the lock with internal threads in the external housing and ‘female Luer fitting’ is used for the one with external threads at the base of the taper.

Note: If it says on the syringe needle packing that it has the Luer Lock Fitting, both types of syringe tips i.e. The Luer Slip Tips and The Luer Lock Tips, can be used with those needles.

Difference in Uses

Luer Slip syringes  Measurement of liquids used for dilution/mixtures.	Luer Lock syringes  are Ideal equipment for septum puncturing in samples with air-sensitivity.
For measuring and removing cuts (dose reduction).	Minimize the possibility of scratches Suitable for washing tubes of small volume.

The size of the needle depends upon the target amount of liquid that will be used to make the dilution and the size (in mL) of the cut that will be made in dilution.

Which to Choose: Luer Slip or Luer Lock?

Today, the main goal of designing medical equipment is to find that fine line between effectiveness and functionality. The effectiveness of equipment considering its designated job is just as important as is its functionality for the individual using the equipment.

Following analysis will help you in making the right selection.

Note: The staff using the syringes may have other preferences for particular tasks based on personal experience and comfort.

Luer Slip Syringes	Luer Lock Syringes
No locking mechanism.	A firm and secure locking mechanism.
Useful for any task where one fluid needs to be filled in multiple adaptors.	Useful for any task where securing the needle is essential.
Easy and quick needle change. (Simple insertion of needle into the syringe.	Takes a few seconds to change the needle.
Quick to fit.	Takes a moment to screw the needle on the tip.
Most refillable cartridges are compatible with Luer Slip Tips.	Suitable with pyrophoric needles.
Cartridge priming, flushing/purging	Most reliable for venous lines or ports to arteriolar lines.
The needle is kept in place by friction. Oil/grease on the needle can loosen the connection of needle and tip.	The screw thread locks the needle in position firmly. Needle will face greater resistance for detachment.
Under high pressure, the Luer joint can burst apart when used with syringe filter.	This connection can withstand high pressure. In case of risk of joint bursting, Luer Lock syringes should be used.