Luer Fitting Testing


Luer fittings (6% taper) are used in many medical devices, including hypodermic needles, syringes, catheters and infusion devices. A Luer fitting is the most common means of achieving a leak-free connection between two medical devices that carry small volumes of fluids.

There are two types of Luer fittings, Luer slip and Luer lock. A Luer slip fitting consists of a tapered cone and a mating tapered cavity. A Luer lock fitting consists of a Luer slip fitting with locking threads added. The Luer lock fitting creates a more secure connection and is therefore the more popular of the two. DDL tests both standalone Luer adapters and Luers which are components of various devices.

ISO 594 - Primary Test Standard for Luer Fittings

The primary standard for dimensional and performance requirements of Luer fittings is ISO 594; Conical fittings with a 6% (Luer) taper for syringes, needles and certain other medical equipment. It consists of two separate standards, ISO 594-1 (Part 1: General requirements) and ISO 594-2 (Part 2: Lock fittings), first issued in 1986 and 1991, respectively. The first edition of ISO 594-2 allowed two different configurations of the female fitting thread--either full threads or two short lugs. However, other thread variants were being developed and introduced. In 1996, the European Community issued EN 1707, a European standard with the same title as ISO 594-2, but with two additional thread alternatives for the female fitting. In 1998, the second edition of ISO 594-2 was issued, containing the additional thread designs of EN 1707.

ISO 594 and EN 1707 contain 8 separate tests, some of which are only applicable to Luer lock fittings. Most of these tests require that the sample be assembled to a particular precision steel reference fitting. The purposes of the various tests are outlined below:

  • Gauging: A dimensional check is performed using a calibrated plug gauge.
  • Liquid Leakage: Ensures that the sample Luer does not leak when pressurized with water.
  • Air Leakage: Ensures that the sample Luer does not leak when a vacuum pressure is applied.
  • Separation Force: Ensures that the sample Luer remains attached to the reference fitting when an axial load is applied
  • Ease of Assembly: Ensures that the sample Luer can be assembled with minimum axial force and torque.
  • Unscrewing Torque: Ensures that the sample Luer remains attached under a specific unscrewing (counter-clockwise) torque.
  • Resistance to Overriding: Ensures that the threads cannot be overridden by a specific screwing (clockwise) torque.
  • Stress Cracking: Ensures that the sample Luer does not crack when assembled for 48 hours.

In order to quickly turnaround Luer testing projects, DDL owns one of the largest collections of calibrated reference fittings in the testing industry.  For repeatable and reliable assembly of the sample Luer to a reference fitting DDL uses a Medi-Luer ISO 594 Test Assembly Apparatus.

DDL has tested Luer fittings for many companies seeking to market their products in the United States, Europe, Asia and elsewhere. Many additional industry standards require testing per ISO 594 including ISO 7864, ISO 7886, ISO 8536, ISO 8537, ISO 10555, ISO 11070, JIS 3209, JIS 3211, JIS 3223 and JIS 3228. Our testing can also be used to qualify new molds.

ISO 80369 - Small Bore Connectors

As the number of medical devices utilizing Luer connectors increased, a rising number of misconnections in the field were reported.  In response to this risk, ISO 80369 was introduced in 2010. Part 1 (ISO 80369-1) addresses general requirements and the remaining parts (ISO 80369-2 through -7) address specific applications.  The overall intent of the standard is to reduce the risk of misconnection by creating six separate application-specific connectors which cannot interconnect with one another. 

ISO 80369-1: General Requirements became available at the end of 2010. While the timeline for introduction of sections 2 – 7 does not appear certain, ISO 80369-1 Annex B provides a test method intended to demonstrate that two connectors cannot be connected.  Like ISO 594 ISO 80369-1 is an FDA Recognized Consensus Standard and as such, medical device manufacturers have been held to this standard.  Eventually, ISO 80369 part 7 will replace ISO 594 as the relevant test standard for Luer connectors.

ISO and EN Test Standards for Luer Fittings 

  • ISO 594-1 - Conical fittings with 6% (Luer) taper - Part 1: General requirements
  • ISO 594-2 - Conical fittings with 6% (Luer) taper - Part 2: Lock Fittings
  • EN 1707 - Conical fittings with 6% (Luer) taper - for syringes, needles and certain other medical equipment - Lock Fittings
  • EN 20594-1 - Conical fittings with 6% (Luer) taper - for syringes, needles and certain other medical equipment - Part1: General Requirements

If your device includes a Luer fitting and you need independent testing to support a 510(k) or for any other reason, call DDL for a prompt quotation.  For more information on any of DDL's package, material or product testing services, please contact us or Ask one or our testing engineers.

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DDL’s testing laboratories are located in Eden Prairie, MN and Fountain Valley, CA. Learn more about the different testing services provided at each location.

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