Written and maintained by CASRAI Editorial Board
Last updated
This page describes products and general use; it is not medical advice.
A female Luer lock is the receiving half of a threaded Luer connection: the socket-type fitting found on a needleless connector, IV tubing end or catheter hub that a male Luer tip (for example a syringe tip with a locking collar) screws into. It is used by clinic and hospital staff, supply buyers and students who need to tell which Luer fitting is which.
What a female Luer lock is
A Luer connector is a small-bore fitting for joining medical devices that carry liquids. Every Luer connection has two halves: a male fitting and a female fitting. The female fitting is the socket that receives the male tip. In a Luer lock version, the pair also engages through threads, so the two parts are screwed together instead of only pushed together. In a Luer slip version, the parts are held by friction alone (Wikipedia, Luer taper, checked 2026-10-30).
The international standard that covers these fittings for intravascular and hypodermic use, ISO 80369-7:2021, names them directly: its scope lists hypodermic syringes and needles and intravenous cannulae with “male and female Luer slip connectors and Luer lock connectors” (Austrian Standards catalogue entry for ISO 80369-7:2021, checked 2026-10-30).
How it is built and how it connects
Luer fittings are tapered: the male tip and the female socket have matching conical surfaces that seal when pushed together. The nominal taper is 6 percent, which is a ratio and not a six-degree cone angle (Wikipedia, Luer taper, checked 2026-10-30). A lock fitting adds a threaded feature so the connection resists accidental separation; a slip fitting does not have this feature. The thread and tolerance dimensions are set in the standard itself.
ISO 80369-7 notes that the Luer connector was originally designed for use at pressures up to 300 kPa (Austrian Standards catalogue entry, checked 2026-10-30).
Female and male Luer fittings: types and variants
| Fitting | Typical use named in the standard | Key difference |
|---|---|---|
| Female Luer lock | Female connectors on intravascular and hypodermic devices (ISO 80369-7:2021 scope) | Socket half; engages the male tip by threads |
| Male Luer lock | Syringes, needles and IV cannulae (ISO 80369-7:2021 scope) | Tip half; engages the female socket by threads |
| Female Luer slip | Same device classes as above (ISO 80369-7:2021 scope) | Socket half; held by friction only |
| Male Luer slip | Same device classes as above (ISO 80369-7:2021 scope) | Tip half; held by friction only |
Male Luer lock versus female Luer lock
The two are the mating halves of one connection. A male Luer lock cannot connect to another male fitting, and a female cannot connect to another female; a connection needs one of each. The lock or slip style is a separate property from male or female.
Where it sits in the standards landscape
Luer connectors are one family inside a wider set of small-bore connector standards. The FDA describes small-bore as a connector opening of less than 8.5 millimeters. The ISO 80369 series exists to “reduce the likelihood of medical device misconnections”, with designs “intended to physically prevent connections with devices used for other medical applications” (FDA, Reducing Risks through Standards Development for Medical Device Connectors, checked 2026-10-30).
| Standard part | Application |
|---|---|
| ISO 80369-1:2016, Part 1 | General requirements |
| Part 3 | Enteral applications |
| Part 5 (IEC) | Cuff inflation |
| Part 6 | Neuraxial applications |
| ISO 80369-7:2021, Part 7 | Intravascular or hypodermic applications (the Luer connectors discussed on this page) |
| Part 20 | Common test methods |
Source for the table: FDA connectors page, checked 2026-10-30. ISO 80369-7:2021 was issued on 2021-05-04 and is titled “Small-bore connectors for liquids and gases in healthcare applications, Part 7: Connectors for intravascular or hypodermic applications”. It does not specify requirements for haemodialysis-equipment connectors or infusion-system closure-piercing connectors.
How to choose
The main selection point is application: the intravascular and hypodermic connector family is the one covered by ISO 80369-7, and other applications such as enteral or neuraxial use have their own, deliberately different connector designs. Match the connector to the device manufacturer’s instructions for use, and confirm that the fitting is labelled for the intended application.
Safe use and handling basics
- Follow the device manufacturer’s instructions for use for every connection.
- Connect only fittings designed for the same application; the purpose of the ISO 80369 series is to prevent misconnections between different medical applications (FDA, checked 2026-10-30).
- Check that a male and a female half are being joined, and that the lock style on one side matches the other.
Common mistakes
- Treating “female” and “lock” as the same property; they describe different features.
- Assuming every small-bore connector is a Luer; enteral and neuraxial connectors follow other parts of the ISO 80369 series.
- Reading the 300 kPa design origin as a rating for a specific product; pressure limits belong to the product’s own instructions for use.
Where you will see it in practice
Luer fittings appear across infusion and injection products. On this site, see how they feature in microdrip sets, Buretrol burette sets, Y-site injection ports, 10 mL syringes, low dead space syringes and vented needles. Related products are listed in the lac.us category for infusion supplies.
FAQ
What is the difference between a male and a female Luer lock?
The male is the tip half and the female is the socket half of the same connection. Both can be lock (threaded) or slip (friction) style, and a connection needs one of each.
Which standard covers Luer connectors?
ISO 80369-7:2021 covers connectors for intravascular or hypodermic applications and lists male and female Luer slip and Luer lock connectors in its scope (checked 2026-10-30).
Sources
- Austrian Standards, ISO 80369-7:2021 catalogue entry (reproduces the ISO scope): https://austrian-standards.at/en/shop/iso-80369-7-2021-2021-05-04~p2580404 (checked 2026-10-30)
- FDA, Reducing Risks through Standards Development for Medical Device Connectors: https://www.fda.gov/medical-devices/medical-device-connectors/reducing-risks-through-standards-development-medical-device-connectors (checked 2026-10-30)
- Wikipedia, Luer taper (general background on taper and lock versus slip; secondary source): https://en.wikipedia.org/wiki/Luer_taper (checked 2026-10-30)
