Written and maintained by CASRAI Editorial Board
Last updated
This page describes products and general use; it is not medical advice.
A nasogastric (NG) tube is built from a few parts that each decide what the tube can safely do: the connector, the number of lumens, the material, the French size, the length, and optional features such as a stylet and markings. This guide names each part, says what it affects, and maps the common complications to the part that influences them. Who uses it: clinic and ward staff, procurement and supply teams, and students learning the equipment.
What a nasogastric tube is
A nasogastric tube is a flexible tube passed through the nose, down the oesophagus and into the stomach, generally used for enteral feeding and/or gastric drainage (Compat, manufacturer guide, 31 Jan 2022). In US regulation, 21 CFR 876.5980 describes the device as flexible or semi-rigid tubing used for instilling fluids into, withdrawing fluids from, splinting, or suppressing bleeding of the alimentary tract, and the list of named devices includes the feeding tube, the Levine tube and the nasogastric tube. The same paragraph says such a device may include an integral inflatable balloon for retention or hemostasis. For the broader picture, see what a nasogastric tube is.
Parts and features of a nasogastric tube
The manufacturer guide states that tubes differ in intended use, connector type, material, size and length, and that intended use drives the connector, the number of lumens and the material. The table lists each part and what the guide says about it.
| Part or feature | What the manufacturer guide says | Why it matters |
|---|---|---|
| Connector | Oral/Luer, stepped or funnel type, ENLock, or ENFit (see next section) | Decides compatibility with syringes, administration sets and drainage systems, and the risk of misconnection |
| Lumen (channel) | Drainage tubes: single or double lumen. Feeding tubes: single lumen. Feeding and drainage tubes: up to three lumens and multiple ports | Matches the tube to feeding, drainage, or both through one tube |
| Material | PVC, silicone or polyurethane | Affects stiffness, clogging, kinking and the duration of use the manufacturer specifies |
| French size (Fr) | Outer diameter; each Fr step is 0.33 mm | Smaller bore is associated with comfort; larger lumen is less likely to clog |
| Length | Adult tubes 90 to 165 cm | Gastric feeding tubes are typically 90 to 120 cm; nasojejunal tubes 120 to 165 cm |
| Stylet | Stiffens the tube and reduces kinking; use is subject to local regulations, so tubes are sold with and without | Changes what is in the pack |
| Radio-opaque body or markers | Tubes can be fully radio-opaque or carry radio-opaque markers | Makes the tube visible on X-ray imaging |
| Depth markings | Printed along the tube | A depth reference along the tube length |
| Colour and transparency | Transparent tubes let staff see fluid in the tube | Makes obstructions easier to identify; the guide notes carers and patients may prefer not to see the contents |
Connectors
The connector is the part most tied to patient safety. The manufacturer guide describes four types:
- Oral/Luer: the most widely used connector across delivery systems, which is why it carries a misconnection risk.
- Stepped or funnel type: used with drainage or aspiration systems; drainage tubes use a funnel connector.
- ENLock: predates ENFit; incompatible with IV systems but compatible with some drainage and aspiration connectors.
- ENFit: a global standard connector designed specifically for enteral feeding and incompatible with IV and other systems, which helps prevent misconnections.
For syringes and flushing equipment used with these connectors, see irrigating a nasogastric tube: equipment and general practice.
Sizes and materials
NG tubes typically range from 3.5 Fr for neonates to 14 Fr for adults, and up to 24 Fr for triple-lumen gastric feeding and drainage tubes (Compat, 2022). The guide says tubes of 8 to 12 Fr are generally for feeding, while those above 12 Fr are generally for drainage because the larger lumen is less likely to clog. Small-bore tubes (under 12 Fr) are associated with comfort and fewer feeding complications such as rhinitis, oesophageal reflux, oesophagitis and stricture. A full adult French chart is in NG tube sizes for adults.
| Material | Properties stated by the manufacturer | Duration stated (per manufacturer specification) |
|---|---|---|
| PVC | Single-use, commonly used for drainage tubes; stiffer, so less likely to clog; lower biocompatibility and can stiffen over time with gastric acid | Up to 7 days |
| Silicone | Soft, flexible, highly biocompatible; higher risk of kinking | Up to 6 weeks |
| Polyurethane | Softer than PVC but more rigid than silicone; softens at body temperature; thinner walls allow a larger lumen at the same outer diameter | Up to 6 weeks |
These durations come from one manufacturer’s educational guide and refer to its own specifications; the instructions for use of a specific product govern.
Classification of the tube in US regulation
In the FDA product classification database, product code BSS is “Tube, Nasogastric”, device class 2, under regulation number 876.5980 (openFDA, data last updated 2026-10-19). A separate code, PSB, covers the “Nasogastric Feed Tube Kit”, also class 2. The regulation text itself names no connectors, stylets or other components, so the parts above come from manufacturer information rather than from the CFR. The regulation also lists the dissolvable nasogastric feed tube guide as a class I device.
Complications and the part that influences them
The manufacturer guide names five complications. The table links each to the product feature associated with it. This is general product information, not a clinical protocol, and it gives no steps for handling any of them.
| Complication named | Product feature involved | Product note |
|---|---|---|
| Tube misplacement | Radio-opaque body or markers | Radio-opaque tubes or markers are visible on X-ray imaging |
| Migration or loss | Depth markings | Markings give a depth reference along the tube |
| Obstruction (clogging) | Lumen size, French size, material | Larger lumens and stiffer PVC are described as less likely to clog |
| Aspiration | Not tied to one part | A clinical matter outside the scope of this product guide |
| Misconnection | Connector | ENFit is designed to be incompatible with IV and other systems |
How to unclog a nasogastric tube
This page gives no unclogging method. Clearing a blocked tube is a clinical decision for the care team, following the product’s instructions for use. What the product design contributes is limited to the features above: a larger lumen and a stiffer material such as PVC are described as less likely to clog, while silicone carries a higher risk of kinking. General causes are covered in feeding tube clog.
Common mistakes
- Assuming all connectors fit the same syringes: legacy connectors are compatible with one another, which is the source of misconnection risk.
- Treating a feeding tube as a drainage tube, or the reverse: the guide ties narrower bores to feeding and larger lumens to drainage.
- Reading material duration as universal: the 7-day and 6-week figures are the manufacturer’s stated specifications.
- Expecting the CFR to define the components: it does not.
FAQ
What are the parts of a nasogastric tube?
The connector, one to three lumens, the tube body in PVC, silicone or polyurethane, a French size and length, and optional features: a stylet, radio-opaque markers and depth markings.
How do you unclog a nasogastric tube?
This page gives no method. A blocked tube is handled by the care team following the product’s instructions for use; the section above covers how lumen size and material relate to clogging.
What complications can a nasogastric tube cause?
The manufacturer guide names misplacement, migration or loss, obstruction, aspiration and misconnection; see the complications table above.
How does a nasogastric tube differ from other feeding tubes?
It passes through the nose into the stomach. Related comparisons: Dobhoff vs nasogastric tube and gastrostomy tube vs nasogastric tube.
Sources
- Compat, “A guide for selecting the appropriate nasogastric tube”, 31 January 2022 (manufacturer educational guide), PDF; checked 2026-10-30.
- 21 CFR 876.5980, Gastrointestinal tube and accessories, Cornell LII; checked 2026-10-30.
- openFDA device classification, product code BSS, API record (data last updated 2026-10-19); checked 2026-10-30.
