NG Tube Sizes and Colors-GCMEDICA

NG Tube Sizes and Colors

May 16,2025

Nasogastric (NG) tubes are graded by the French (Fr) scale, in which each unit equals one‐third of a millimeter in external diameter. To facilitate rapid identification, many manufacturers apply color‐coding to the tube or its connector. This system helps clinicians select the appropriate size at a glance, improving workflow efficiency and reducing errors. Below is a summary of common adult and pediatric NG tube sizes with their corresponding outer diameters, typical color markers, and clinical applications.

French Size (Fr)	Outer Diameter (mm)	Color Code¹	Typical Use
6 Fr	2.0 mm	Pink	Neonatal feeding; minimal gastric decompression
8 Fr	2.7 mm	Yellow	Infant feeding; medication delivery
10 Fr	3.3 mm	Blue	Bolus or continuous feeding in older infants and small children
12 Fr	4.0 mm	Green	Pediatric feeding; gastric aspiration
14 Fr	4.7 mm	Orange	Adolescent enteral nutrition; lavage
16 Fr	5.3 mm	Red	Adult feeding; decompression in partial obstruction
18 Fr	6.0 mm	Purple	Gastric lavage; charcoal administration in overdose

¹ Color conventions may vary by manufacturer; always verify labeling.

Clinicians choose smaller-bore tubes (6–10 Fr) for neonates, infants, and when only minimal feeding or medication delivery is required, minimizing mucosal trauma and discomfort. Medium sizes (12–14 Fr) balance nutritional support and gentle aspiration, making them ideal for pediatric and adolescent patients. Larger tubes (16–18 Fr) provide efficient gastric decompression, lavage, or administration of thick suspensions in adult patients.

Key Selection Considerations:

Patient Anatomy: Smaller sizes protect delicate nasal and esophageal mucosa in neonates and infants. Larger diameters prevent clogging when aspirating viscous fluids.
Clinical Purpose: Feeding and medication use require narrower bores to maintain comfort; decompression or lavage demands wider lumens for rapid drainage.
Connector Compatibility: ENFit-compliant enteral connectors (often purple) reduce misconnection risks; Luer-lock adapters enable syringe attachment for aspiration or contrast studies.
Length Measurement: Use the NEX (Nose–Ear–Xiphoid) method to estimate insertion depth for accurate placement and reduced migration risk.

By combining standardized sizing with color-coding, NG tubes offer a simple, reliable system for matching tube diameter to patient age, anatomy, and clinical requirement—streamlining preparation and enhancing patient safety.