A Foley catheter is one type of indwelling catheter, but the two terms aren’t perfectly interchangeable. “Indwelling” simply means any catheter designed to stay in the body for a period of time, while “Foley” refers to a specific design that passes through the urethra and uses a small inflatable balloon to hold itself in place inside the bladder. In everyday hospital conversation, nurses and doctors often use the terms as synonyms because the Foley is by far the most common indwelling catheter. But other indwelling designs exist, which is why the distinction matters.
How a Foley Catheter Works
A Foley catheter is a flexible tube with two internal channels. One drains urine from the bladder into a collection bag. The other connects to a small balloon at the catheter’s tip. Once the tube is inserted through the urethra and into the bladder, a healthcare provider fills that balloon with sterile water. The inflated balloon is too large to slip back through the bladder neck, so the catheter stays put without tape or stitches. When it’s time for removal, the water is drawn back out and the catheter slides free.
Most adult Foley catheters range from 14 to 16 French (a sizing scale where each unit equals about a third of a millimeter in diameter). The general rule is to use the smallest size that still drains well, which reduces irritation to the urethra.
Other Types of Indwelling Catheters
The main alternative is a suprapubic catheter. Instead of entering through the urethra, this catheter is inserted through a small surgical opening in the lower abdomen directly into the bladder. It’s placed under anesthesia and is typically used when the urethra is damaged, blocked, or when someone can’t manage a urethral catheter. Like a Foley, it stays in place continuously and drains into a leg bag or can be fitted with a valve that opens over a toilet. Suprapubic catheters are usually changed every 4 to 12 weeks.
Both the Foley and the suprapubic catheter are indwelling catheters. The key difference is the entry point: urethra versus abdomen. A third category, the intermittent catheter, is not indwelling at all. It’s inserted to drain the bladder and then removed immediately, several times a day.
Why the Terms Get Swapped So Often
In most clinical settings, when someone says “indwelling catheter,” they mean a Foley. Roughly 12% to 16% of adult hospital inpatients have an indwelling urinary catheter at some point during their stay, and the vast majority of those are Foleys. Suprapubic catheters are far less common and are usually described by name specifically because they require a surgical procedure to place. So while “indwelling” is technically the broader category, using it as shorthand for “Foley” rarely causes confusion in practice.
When Indwelling Catheters Are Used
Indwelling catheters aren’t placed casually. According to guidelines from the Agency for Healthcare Research and Quality, appropriate reasons include acute urinary retention or blockage, certain surgeries (placed beforehand and ideally removed within 24 hours), situations requiring precise urine output measurement in critically ill patients, trauma or surgery that demands strict immobilization, healing of severe wounds in the pelvic area, and comfort care for patients in hospice. Outside these scenarios, the preference is to avoid indwelling catheters or use intermittent catheterization instead.
Infection Risk With Indwelling Use
The biggest concern with any indwelling catheter is urinary tract infection. Each day the catheter remains in place, the risk of developing a catheter-associated UTI rises by 3% to 7%. That daily accumulation is why healthcare teams review catheter necessity on a daily basis and aim to remove them as soon as possible. CDC guidelines recommend against changing catheters on a fixed schedule. Instead, they should be changed only when there’s a clinical reason: signs of infection, blockage, or a break in the sealed drainage system.
Catheter Materials and Comfort
Indwelling catheters come in different materials, and the choice affects comfort and how long the catheter can stay in place. Latex is the traditional material, but some people have latex allergies, and uncoated latex can irritate the urethral lining. Many modern latex catheters are coated with a water-absorbing polymer layer that creates a slippery, protective surface between the latex and the tissue. These coated catheters produce minimal urethral inflammation and lower friction than even some newer alternatives.
Silicone catheters are fully biocompatible and a good choice for patients with latex sensitivities. Because silicone is stronger than latex, the catheter walls can be thinner, leaving a wider internal channel for urine to flow through. Silicone catheters also resist kinking and cause fewer long-term urethral strictures. The tradeoff is that silicone tends to be stiffer, which can mean more discomfort, and silicone catheters are more prone to mineral buildup and blockage over time compared to coated latex versions.
For short-term hospital stays, the material difference is minor. For people who need a catheter for weeks or months, the choice between silicone and coated latex is worth discussing with a healthcare provider, since the right fit depends on individual anatomy, allergy history, and how the catheter will be managed at home.