What is an ISO 80369-7 Compliant Luer? – The New Luer Standard

Luers for medical applications and the new ISO 80369 small-bore connector standards

What is ISO 80369 and how does it relate to luers?

The ISO 80369-7: Connectors for Intravascular or Hypodermic Applications standard for luer fittings is part seven of ISO 80369. ISO 80369 is a series of medical device standards developed by the International Organization for Standardization. The standards cover small-bore connectors used in the different systems providing direct, individual patient care. ISO 80369 standards were developed to significantly improve patient safety. They do this by minimizing the risk of misconnection between different fluid and gas delivery lines.

As of December 31, 2019, the FDA will no longer accept new medical device designs for intravascular or hypodermic applications that incorporate luers that do not comply with the ISO 80369-7 standard. The ISO compliance deadline for existing products is October 15, 2021.

Figure 1 is the SEGD, Society for Experiential Graphic Design universal symbol for intensive care.

Check out ISM’s selection of ISO 80369-7 compliant luer connector components >>

How does ISO 80369 improve patient safety?ISO 80369 applies to small-bore connectors used in medical devices or accessories intended for patient-side care. The core of these standards are new connector types that minimize the possibility of interconnections. There are ISO 80369 connector standards for each of five major types of fluid or gas delivery systems used in direct patient care. For luers, ISO 80369-7 provides revised dimensions and tolerances as well as testing procedures for confirming luers meet these standards.

The general categories of medical devices covered in the ISO 80369 standards

  • Intravenous (IV) or hypodermic applications (80369-7)
  • Breathing systems and gas driving applications (80369-2)
  • Enteral applications such as feeding tubes (80369-3, ENFit®)
  • Limb cuff inflation applications such as blood pressure cuffs (80369-5)
  • Neuraxial applications such as epidural anesthesia catheters (80369-6, NRFit™)

Learn more about the ISO 80369 standard on this ISO 80369, Small-Bore Connectors for Liquids and Gases in Healthcare Applications page of the ISO Online Browsing Platform.

What is a medical device?As far as the FDA is concerned, a medical device can be as simple as a tongue depressor or a luer connector. It can also be as complex as a robotic surgical system. Medical devices even include products such as the general-purpose lab equipment used for in vitro diagnostic testing. In vitro lab testing is done in test tubes or culture dishes.

If a product is used for medical purposes and it meets the definition of a medical device it is subject to FDA medical device rules. This definition comes from section 201(h) of the Federal Food Drug and Cosmetic (FD&C) Act. FDA oversight includes both pre-market and post market regulatory controls.

Figure 2 is a FLB7 series male luer lock by hose barb filter. These fittings are ISO 80369-7 compliant for intravascular (IV) applications.

Here are two resources on the FDA website that provide some detailed background for understanding what medical devices are:

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What are small-bore connectors?In patient care settings such as hospital bedsides and outpatient clinics, small-bore connectors and connections are used to combine the different medical devices, components and accessories of a gas or liquid delivery system. The connected parts include such things as tubing, syringes, fluid bags, gas lines, filters, backflow preventers and so on. In combination, these parts make up sub-assemblies and assemblies.

The most familiar types of assemblies are called tube sets or tubing sets. They deliver the fluids or gases needed for direct patient care. The connectors in these assemblies are called small-bore connectors because of their size. The bores or holes running through them have diameters less than 8.5 millimeters.

ISO 80369 standards minimize the chance of misconnectionsMisconnections have caused patient injuries and death in the past and represent a significant ongoing risk. This risk has been increasing over time because of the growing complexity of medical care. ISO 80369-7 Connectors for Intravascular (IV) or Hypodermic Applications applies to luer connectors and is one of these new medical small-bore connector standards intended to reduce this risk.

Up till now, luer connectors have been widely used in all sorts of medical, patient-side fluid and gas delivery systems. The new standards are intended to make luers only connectable within IV and hypodermic applications.

Find out more about ISO 80369-7 as an effort to improve patient safety: Reducing Risks through Standards Development for Medical Device Connectors at the FDA website.

Luers are a small-bore connectorLuers are one of many types of small-bore connectors. Luers are wonderfully well designed and provide an easy-to-manage, leak-free connection between a tapered male fitting and its female mating part. The luer’s design provides a friction fit that can be easily loosened and then reconnected.

Despite what you might think, the luer design is over 100 years old. It was initially developed as a connection tip for glass syringes. Because it is both leak-free and easy to use, the luer quickly became a critical low-cost component extensively used for intravascular, neuraxial, enteral, medical gas and monitoring applications.

C V 7 series male luer lock by hose barb check valve plastic fittings.
Figure 4
Male and female luer thread fittings

Luers also have uses beyond medical care. They are a type of connector commonly found in modern commercial industrial applications. Uses include printer ink management, labware and lab equipment, dispensing systems and biopharmaceutical processing.

Figure 4 shows a male luer thread by barb fitting on the left and a female luer thread by barb fitting on the right. These are CV7 series luer lock by hose barb filtered check valves. These fittings are ISO 80369-7 compliant for intravascular (IV) applications.

What exactly is a luer?A luer is a standardized connection type based on a conical taper design. This taper is 6% or 1.72 degrees from the centerline. This taper is often referred to as the luer taper. Luer fittings rely on this taper and the friction between the mating surfaces to provide quick, tight, leak-proof seals between male and female luers.

The basic luer is called a slip luer or luer slip because of how the connection is made. There is also a more secure version called the luer lock. It relies on special threads to create a more secure connection that does not rely on friction alone to maintain the connection.

What is a luer lock?The luer lock was developed in 1925. Lure lock fittings have special threads added to the luer taper. Male luer locks have internal threads molded into a housing surrounding the male luer. These threads interlock with external threads or lugs added to female luer fittings.

Luer locks add mechanical strength to luer connections. They also help prevent accidental disconnections and create tighter seals. Luer lock connections are easy to take apart and secure. This is the primary reason they have become standard for syringes as well as being widely adopted for other applications.

Figure 5 is a FCV7 series male luer lock by hose barb filtered check valve. These check valves are ISO 80369-7 compliant for intravascular (IV) applications.

ISO 80369 and other luer standardsThe ISO has published standards for luer fittings since 1969. The first version of these is called ISO 594-1 and it covers slip luer fittings. A related ISO standard, ISO 594-2, was issued in 1991 and it covers luer lock fittings.

ISO 80369-7 was published in October 2016 and replaces both ISO 594-1 and 594-2. The FDA has previously required that luer connectors meet the ISO 594 standards. The FDA has begun requiring medical device luers used in direct patient care comply with ISO 80369 and ISO 80369-7.

Medical device manufacturers have an ISO 80369 compliance deadline for luersAfter December 31st, 2019, the FDA no longer accepts new product submissions of medical device designs for intravascular or hypodermic applications that include luer connectors based on the older ISO 594 standards. Instead, luer connectors for these applications need to comply with ISO 80369-7 standards.

There is good news for biopharmaceutical, laboratory, chemical handling and other luer connector users. ISO 80369-7 compliant luers are designed to be backward compatible with ISO 594 luers. Keep in mind that ISO 80369-7 has replaced the ISO 594 standards for luer connectors.

An important point for all plastic luer usersThe ISO 80369-7 luer standard specifications include a particular measurement called the ‘t’ dimension. The ‘t’ dimension is from the end of the male luer tip up to the first fully formed thread.

The ‘t’ dimension was subject to interpretation in the previous ISO 594 standards for luers. The result is that you may sometimes run across fit issues between the newer ISO 80369-7 compliant luers and luers manufactured under the older ISO 594 standards.

Figure 6 is a technical drawing showing the ISO 80369-7 luer standard’s ‘t’ measurement.

For more information about compatibility between ISO 80369-7 and ISO 594 luers, check out “ISO 80369-7 luer standard: What this means for plastic luer users” at MPN, Medical Plastics News.

Key takeaways about ISO 80369-7 and luersThe FDA deadline has passed for new medical device design submissions that use luers in sub-assemblies, assemblies, tubing sets and other intravascular (IV) delivery systems. If a luer connector is part of a new medical device or accessory intended for direct patient care, that luer will almost certainly need to be compliant with ISO 80369 regardless of the connector's exact role.

These new standards provide important improvements in quality, safe patient care. Because of this, medical device manufacturers have also begun incorporating new ISO 80369-7 luers into their existing patient side medical applications.

Medical device compliance standards are a complicated subject. This article is only a very simplified introduction to ISO 80369 and the new ISO 80369-7 luer standards. It is intended for general reference purposes only. It is the responsibility of the user, designer or engineer to evaluate all components in consultation with an appropriate compliance specialist for safety and suitability of use.

A good starting point for learning more about FDA medical device compliance is this article on the FDA website:
Quality and Compliance (Medical Devices)

Some other ISO 80369 compliant small-bore connector types available from ISMISO 80369 standards have been developed to prevent misconnection between small-bore connectors used in different applications. It ensures correct connections even in complex working environments.

ISO 80369-3 Enteral Feeding ConnectorsThe enteral feeding connector standard, ISO 80369-3 (ENFit®), was published July 2016 and recognized by the FDA September 2016. ENFit® is a trademark of the industry group Global Enteral Device Supplier Association (GEDSA). The ISO 80369-3 standard covers connectors for the complete enteral system, except reservoir connectors which are covered by ISO 18250-2.

Figure 7 is an ENT series male enteral connector by bond-in port plastic fitting. These fittings are ISO 80369-3 compliant for enteral feeding applications.

An important note about ISO 80369-3 Enteral Feeding Connectors:
The FDA recommends hospitals and clinicians use enteral devices with connectors that meet the ISO 80369 standard >>

More about enteral feeding (ENFit ®) connectorsENFit ® connectors are incompatible with luer connectors. They also do not interconnect with any other non-luer, non-enteral connectors used for patient side clinical applications. These include tracheostomy tubes, IV lines, limb cuff inflation lines, neuraxial lines and catheters. This fit and no-fit usability is provided by the ENFit ® connector’s larger size as well as its overall design.

What is enteral feeding?Enteral feeding usually refers to a method of feeding that delivers food or nutrition through a tube (tube feeding) that goes directly to the stomach or small intestine. People receiving enteral feeding usually have some sort of medical condition or injury that prevents them from eating their regular food.

Enteral feeding is usually a practical option in cases where someone's digestive system (GI tract) is still working just fine. In fact, a benefit of enteral feeding in these cases is that it helps keep their GI tract working properly. Enteral feeding can provide for a person's entire caloric needs or it may be used to provide supplementary nutrition.

Find out more about the ISO 80369 standard for enteral feeding connectors at the ISO website:
ISO 80369-3:2016 >>
Small-bore connectors for liquids and gases in healthcare applications — Part 3: Connectors for enteral applications.

ISO 80369-5 Limb Cuff ConnectorsThe ISO 80369-5 standard for limb cuff inflation application small-bore connectors was originally approved and published March 2016. This standard was recognized by the FDA August 2017. This standard is based on a bayonet style connection.

Figure 8 is a BPM5 blood pressure limb cuff bayonet connector by hose barb plastic fitting. These fittings are ISO 80369-5 compliant for limb cuff inflation applications.

What applications use limb cuff inflation?Limb cuff inflation applications include blood pressure cuffs, tourniquet cuffs and surgical tourniquets. The new ISO 80369 worldwide standard for these bayonet-style connectors does not allow interconnection with either luer or other, non-luer connectors used for patient-side clinical applications. This fit and no-fit usability is provided by the bayonet-style design of the connectors.

Like the other ISO 80369 standards, ISO 80369-5 significantly reduces the risk of dangerous and potentially fatal misconnections.

Find out more about the ISO 80369 standard for limb cuff inflation connectors at the ISO website:
IEC 80369-5:2016 >> Small-bore connectors for liquids and gases in healthcare applications — Part 5: Connectors for limb cuff inflation applications

ISO 80369-6 Neuraxial ConnectorsThe ISO 80369-6 (NRFit™) standard for neuraxial application small-bore connectors was originally approved and published March, 2016. This standard was recognized by the FDA June 2016. NRFit™ is a trademark of the Global Enteral Device Supplier Association (GEDSA).

Figure 9 shows female (top) and male (bottom) NXL6 neuraxial by bond-in port plastic fittings. These fittings are ISO 80369-6 (NRFit™) compliant for neuraxial applications.

More about neuraxial (NRFit™) connectorsNRFit™ connectors have unique design features that dramatically reduce the risk of cross-connections with both luer connectors and non-luer, non-neuraxial connectors. Non-neuraxial patient-side applications may include tracheostomy tubes, IV lines, limb cuff inflation lines, neuraxial lines and catheters. The fit and no-fit usability is provided by the NRFit ® connector’s smaller size, 20% smaller than luer connectors, in combination with other design features.

What applications use neuraxial connectors?Applications that require neuraxial connectors include spinal anesthesia, intrathecal chemotherapy, lumbar puncture, cerebrospinal fluid collection and pressure measurement, epidural catheter placement with bolus injection and major regional anesthesia.

Find out more about the ISO 80369 standard for neuraxial connectors at the ISO website:
ISO 80369-6:2016 >>

Small bore connectors for liquids and gases in healthcare applications — Part 6: Connectors for neuraxial applications

Figure 10 is a CFL7 series female luer lock or thread by hose barb fitting. These fittings are ISO 80369-7 compliant for intravascular (IV) applications.

A list of references mentioned in this post

Various reference links

ISO (International Organization for Standardization)

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Steven C. Williams headshot March, 2018.

About the authorSteven C. Williams my LinkedIn profile link button.Steven C. Williams, BS, is the technical writer and an inbound marketing specialist at Industrial Specialties Manufacturing (ISM), an ISO 9001-2015 supplier of miniature pneumatic, vacuum and fluid circuitry components to OEM's and distributors all over the world. He writes on technical topics related to miniature pneumatic and fluidic components as well as topics of general interest at ISM.       

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