Luer connector testing

Luer connectors (6% taper) are used in many medical devices, including hypodermic needles, syringes,  catheters, infusion devices, and inflation luments. The Luer connector is ubiquitous in the medical device field and is frequently used when a reliable leak free connection is required. SMTL are able to test Luer fittings for medical devices to the following standards:  ISO 594 - Conical fittings with a 6% (Luer) taper for syringes, needles and certain other medical equipment.  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 a 6 % (Luer) taper for syringes, needles and certain other medical equipment. Lock fittings.

ISO 594 and EN 1707 contain 8 separate tests, some of which are only applicable to Luer lock fittings. The 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 develop stress cracks when assembled for 48 hours.

Non-Luer (neuraxial) testing

Since the report by Prof. Brian Toft into the death of Wayne Jowett in Nottingham in January 2001, there has been much interest in developing new, non-luer compatible connectors to reduce the risk of similar occurrences. SMTL were commissioned by the Dept. of health Patient Safety Team to evaluate a range of connectors designed to avoid wrong route injections, which was part of a larger project which included mannequin testing and user evaluations.

SMTL represent the Welsh Assembly Government on the NPSA External Reference group which has been advising the NPSA on a recent Alert, designed to make the NHS replace luer connectors with non-luer compatible connectors for spinal and epidural devices by 2013.

SMTL's Director, Pete Philips,  chairs the Welsh Assembly's Welsh Neuraxial Connector Reference Group (WNCRG), which is tasked with coordinating and implementing the alert within Wales.

SMTL also sit on the British Standards committee which is developing the International Standard for small bore connectors, designed to eliminate the use of luer connectors from a range of medical devices such as enteral and neuraxial products.

SMTL have developed expertise in testing and assessing non-luer devices, both for the DoH reports and more recently for the planned assessment programme in Wales.  If you have non-luer compatible designs which you wish to have tested, please contact SMTL.