How To Choose The Right Tubing

Fluidic Tubing

OEMs working on next generation diagnostic instruments require the use of various fittings and fluidic tubing to connect the elements of their fluidic system. Choosing the right tubing for their instrument can make the difference between a good design and a great one.

How To Choose The Right Tubing?

Several parameters must be taken into consideration in order to choose the tubing:

  • Tubing dimensions
  • Materials

Tubing Dimensions

Being familiar with tubing dimensions and how each influence tubing selection is helpful in order to make the right tubing choice the first time.

  • “OD” means outer diameter
  • “ID” means inner diameter — Diameter of the fluidic path where fluid flows. The inner diameter plays a significant role in the resistivity brought by the tubing: the smaller it is, the more resistant the tubing will be.
  • “L” means length — Tubing is usually made as short as possible to have smaller internal volumes. The internal volume of the tubing being the inner section times the length of the tubing. It is also a parameter that takes part in the resistivity of the tubing.


Fluidic Tubing: Inches To Millimeters Conversion

In many catalogs, tubing dimensions can be displayed in inches, millimeters and a mixture of the two. The following chart will help conversion between these two systems.

Inches Millimeters
1″ 25.4
1/8″ 3.17
1/16” 1.58
0.040″ 1
1/32” 0.794
0.030″ 0.75
0.020″ 0.5
1/64″ 0.397
0.010″ 0.25
0.007″ 0.175
0.005″ 0.125


A wide range of materials are available for the same ID/OD combination. The material should be selected according to the nature of the reagents flowing through the tubing. Remember to carefully check the chemical and biological compatibilities of the tubing material before installing the tubing on your instrument. Some of the most common materials for fluidic tubing include:

  • PEEK (Polyetheretherketone) — Biocompatible, chemically inert to inorganic and organic solvents, is biocompatible and has low non-specific adsorption. PEEK tubing is flexible, offers a very smooth internal surface and may be easily cut to desired lengths. Suitable for low and high-pressure applications.
  • PFA (Perfluoralkoxy) – An excellent choice for many tubing applications, PFA is chemically inert, non-toxic and exhibits low water absorption and has a very low surface energy. This makes it ideal for handling a variety of fluids including biologicals and corrosives.
  • PTFE (Polytetrafluoroethylene) — Chemically inert to most commonly used solvents, non-toxic, non-porous, excellent stress-resistance, flexible and transparent as well. PTFE exhibits low surface energy and is used mostly for low-pressure applications. PTFE may be used in handling a variety of fluids including biologicals and corrosives.
  • FEP (Fluorinated ethylene-propylene) — Same family as PTFE. Chemically inert to most commonly used solvents and is also biocompatible. Flexible and transparent, FEP is used m Mostly for low-pressure applications. FEP exhibits low water absorption and has very low surface energy.
  • ETFE (Ethylene tetrafluoroethylene) — Same family as PTFE and FEP, but more rigid and better-suited to higher-pressure applications. ETFE is inert to most chemicals and is hydrolytically stable.

About Us

For decades, global OEM leaders in diagnostics, life sciences and medical devices have turned to Diba Industries to solve their most complex fluidic design challenges. During that time, our application engineers have delivered precision fluid handling solutions and manufactured custom components across the entire system fluid path. And, with more than two million fluidic assemblies manufactured annually, that’s a lot of tubing and connections we’ve made for our customers over our 30+ years in business!