When it comes to catheters, patients often favour one material over the others.

According to the Franklin Institute, the first flexible catheter was invented in 1752 by Benjamin Franklin (one of the Founding Fathers of the United States) to help his brother John, who suffered from bladder stones, to urinate. At that time, patients like John had had rigid metal tubes placed into their bladder and the process was excruciating. So Benjamin worked with a silversmith to hinge segments of metal together to form a more flexible tube.

Fast forward to today, metal is no longer the material of choice. Instead, soft but durable plastic (Polyvinyl Chloride or PVC), rubber and silicon are the primary materials used in the production of catheters. In this article, we will look at each material, and discuss why you may see a warning label on some catheters.

Polyvinyl Chloride (PVC)

PVC is a synthetic plastic polymer. PVC catheters are translucent, allowing patients and their medical providers to see the colour of the urine easily. PVC is also firm, but fairly flexible for easy insertion. As PVC materials are usually (but not always) latex-free, they are preferred by those who have a latex allergy.


Silicone is fast becoming the material of choice as critics claim the production, use and disposal of PVC materials create toxic chemicals. Silicone is also clear, meaning patients and medical providers can see the urine easily. In terms of flexibility, it sits somewhere between PVC and latex. As silicone is totally free of latex, it is also a preferable choice for those with a latex allergy. The material is also smooth, and some brands even have an antibacterial coating applied.


Among the three materials, latex is the most flexible due to the material being thermo-sensitive, meaning that it will warm up to the surrounding temperature and, as such, become more flexible. In a 2000 study by the American Family Physician organisation, latex was noted to be cheaper than silicon and as a result, was preferred for long-term catheterisation. However, latex catheters should not be used in latex-allergy patients.

Which material is best?

There is no one right option. The type of material you decide on using should be dictated by your anatomical needs, your situation and your personal preferences. Talk to your medical professionals and discuss openly which works best for your situation and needs.

What are French sizes?

Another consideration, alongside the varying materials, are ‘French sizes’. Internal catheters are sized through the ‘French Size’ – a universal gauge system that is dictated by the size of the tube’s external diameter. This size is determined through a simple formula of multiplying the diameter of the catheter (in mm) by 3. So if the diameter is 4mm, you would times this by 3 to get a 12 French Size (or 12Fr).

Using a catheter with a diameter that is too large for your urethra will make the catheterisation process painful and problematic. On the other hand, if it is too small, the draining process will not only go much slower, but you run the rather messy risk of urine escaping around the tube. This is why it is important to get the right catheter size.

PVC catheter users may notice that French sizes are easily discernible by eye due to the colour coding system used on the funnels that come with PVC catheters. For example, a black funnel is 10Fr; an orange funnel is 16Fr; and a red funnel is 18Fr.

Is PVC safe for catheter use?

An issue that has arisen in recent years has been the controversy surrounding the usage of PVC in products, particularly medical products. This is due to the plasticiser known as DEHP or Di(2-ethylhexyl) phthalate being present in many PVC products. DEHP is used to soften plastics in order for them to be more flexible – as is the case with many PVC catheters.

Since 2015, DEHP was banned from general use under EU law. In July 2018, the EU again voted unanimously to prohibit the use of four phthalates in consumer products as research has indicated they may have damaging effects on reproductive health. The four phthalates are BBP, DEHP, DBP and DIBP. This ban will go into effect in July 2020.

In the meantime, DEHP has been making news across the pond. If you speak with a catheter user in California, they may have mentioned that their PVC catheters now carry a warning. This is because a recent state law (California’s Proposition 65 law) dictates that manufacturers must print a warning on the packaging on products that contain DEHP, along with a comprehensive list of other chemicals. This law is only applicable to California and not other US states.

If you are concerned about DEHP in your PVC catheters, then you may want to explore silicon or latex catheters.

UroShield keeps catheter users safe

No matter what type of catheter you use and what it is constructed of, safe and responsible catheter use is an important part of maintaining bladder and urological health.

As indwelling and suprapubic catheters are kept in place within the body for up to 10 weeks, you will hear your medical providers reminding you time and again about good hygiene. This is because bacteria are everywhere and they can form colonies (known as biofilms) that sit on the surface of your catheter before entering your body and causing catheter-associated Urinary Tract Infections (CAUTIs).

CAUTIs are highly uncomfortable and may even lead to fatality if left untreated. If you suffer from CAUTIs, chances are you would be given antibiotics to combat the infection, but regular usage of antibiotics will reduce or even eliminate the usefulness of them. Thankfully, UroShield is a medical device that connects directly to any indwelling or suprapubic catheters regardless of their materials.

The innovative device works by generating low-frequency, completely painless ultrasound waves that reverberate around the surface of the catheter – stopping the formation of biofilm, thereby reducing the chance of CAUTIs and blockages.

UroShield is portable and completely reusable, meaning if you switch from one catheter to another, you can still use the same device. To keep it clean, simply wipe it with an alcohol or antiseptic wipe. While UroShield is long-lasting, the actuator clip (which connects UroShield to the catheter) must be changed every 30 days.

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If you would like to know more about UroShield and what it can do for you, get in touch on 020 8773 7844 or fill out our Online Form.

This post is not health advice and should not replace professional advice tailored to your specific circumstances. It is intended to provide information of general interest about current healthcare issues.