What Is a Medical Underpad?
A medical underpad is a disposable absorbent pad placed on a bed, chair or examination table to protect the surface and manage moisture. You will hear them called underpads, bed pads, chux, or incontinence pads. In a long-term care home they sit under residents who are incontinent or at risk of skin breakdown; in a clinic they line examination tables and treatment surfaces; in home care they protect mattresses and sofas.
Underpads are not towels with a plastic layer. A proper medical underpad is a layered system — a soft topsheet, an absorbent core with superabsorbent polymer (SAP), and a leak-proof backing — engineered to pull moisture away from skin and hold it in the pad. This article explains how those layers work, how absorbency ratings are expressed, and what the numbers mean when you buy underpads for a Canadian facility.
The Anatomy of an Underpad: Three Layers, One Job
Most disposable underpads use the same basic architecture, and knowing it makes spec sheets readable.
Topsheet
The layer that touches skin is usually a soft non-woven fabric — polypropylene (PP) or, increasingly, a PLA bioplastic alternative. Its job is to wick moisture down into the core and feel dry against the skin. A topsheet that stays wet on the surface defeats the pad's purpose, because prolonged moisture contact is exactly what leads to skin irritation and moisture-associated damage.
Absorbent core
The core is where the pad earns its rating. It combines fluff pulp with superabsorbent polymer (SAP) — the same absorbent chemistry used in adult briefs and baby diapers. SAP granules can absorb many times their own weight in fluid and lock it in a gel, which is why a modern underpad stays functional after a large void while a plain cotton layer would soak through in minutes.
Leak-proof backing
The bottom layer is a polyethylene (PE) film or equivalent barrier that keeps fluid off the mattress or table. The backing is also where manufacturers can cut corners — a thinner film lowers cost but raises the risk of leaks under pressure, particularly when a resident sits or lies on the pad for hours.
Absorbency Ratings: What the Numbers Really Mean
Manufacturers describe underpad absorbency with terms like light, moderate, heavy and extra-heavy, often paired with a millilitre figure. There is no single universal rating standard, which is exactly why buyers should compare pads on measured millilitres rather than adjectives.
| Rating (typical) | Approx. capacity | Common use |
|---|---|---|
| Light | 200–500 mL | Exam table protection, minor drainage, postpartum care |
| Moderate | 500–1,000 mL | Intermittent incontinence, wound drainage, home care |
| Heavy | 1,000–2,000 mL | Night-time incontinence in LTC, immobile residents |
| Extra-heavy | 2,000 mL+ | High-output situations, multiple voids between changes |
For a Canadian long-term care home, the practical question is not the peak millilitre claim but the pad's behaviour under real conditions: does the surface stay dry after a typical void, does the pad hold without leakage when the resident sits, and how often does staff have to change it? A pad that claims 1,500 mL but leaks at the edge after 400 mL is a procurement failure that shows up as extra laundry and skin issues, not as a spec-sheet number.
Size Matters: 30x36 vs 60x90 and Other Common Formats
The two most common underpad sizes in Canada are roughly 30 x 36 inches (about 75 x 90 cm) and 60 x 90 cm — the same pad measured in imperial and metric, which creates endless confusion in ordering. Other common formats include 17.5 x 24 inches for chairs and smaller surfaces, and 23 x 36 inches for half-bed coverage.
Size selection follows the surface and the task. An exam table needs a pad that covers the contact area without excessive overhang. A bed pad for an immobile resident should span the hips-to-knees zone where most moisture exposure happens — a pad that is too small creates a gap at the edges, and a pad that is too large wastes money and complicates repositioning. CliniEco stocks both the 30x36 inch heavy-absorbency underpad and the 60x90 cm 5-layer SAP pad so facilities can standardize on one spec across beds and tables.
Where Underpads Fit in Pressure Injury Prevention
Underpads are part of a skin-care system, not a standalone solution. In pressure injury prevention, the goals are to keep skin clean and dry, reduce pressure and shear, and reposition regularly. An underpad supports the first goal by managing moisture — but only if the topsheet stays dry, the pad is changed on schedule, and the skin is cleansed and moisturized as part of the routine. The CDC isolation precautions guideline and the broader infection-control literature treat moisture management as one element of skin integrity, and the Public Health Agency of Canada resources on continuing care emphasize prevention planning over reactive treatment.
Underpads and Incontinence-Associated Dermatitis
Incontinence-associated dermatitis (IAD) is the skin damage caused by prolonged contact with urine or stool, and it is one of the most common skin problems in LTC. The clinical literature is clear that IAD prevention depends on three actions: gentle cleansing, moisturizing, and keeping the skin dry — and the pad is the mechanical tool for the third one. Studies in the American Journal of Infection Control and Antimicrobial Resistance & Infection Control have examined moisture-associated skin damage and the role of absorbent products in care protocols, and the Infection Control & Hospital Epidemiology journal regularly covers skin integrity as an infection-prevention issue, because broken skin is an entry point for infection.
For procurement, the practical translation is: choose a pad whose topsheet stays dry and whose absorbency matches the change schedule, then make sure the pad is actually part of a documented skin-care routine. The pad alone does not prevent IAD — the protocol does. Buyers should treat underpad selection as a clinical decision with a paper trail, the same way they would treat a wound-care product.
How Underpads Are Disposed Of
Used underpads from a healthcare setting are contaminated waste, and their disposal follows the facility's medical waste stream rather than ordinary recycling. Even PLA-based pads typically go to the same waste path unless the facility has a verified composting or organics route that accepts them. The Waste Management journal has published studies on absorbent hygiene product waste and its environmental load, which is useful background for facilities trying to quantify their disposable footprint. The regulatory side in Canada is handled through provincial waste regulations, and the World Health Organization has issued guidance on safe management of healthcare waste that remains a useful reference for facility policies.
Cost Per Change: The Metric That Drives Underpad Purchasing
Underpads are a volume purchase, so buyers should calculate cost per change, not cost per pack. The calculation has three variables: pad price, changes per day, and the cost of failure (extra laundry, mattress replacement, skin-care products). A cheap pad that leaks forces an extra change cycle and a mattress wash; a heavier pad that holds through the night may actually cost less per resident per day.
Facilities that track this usually find a 5-layer SAP pad outperforms a thin 3-layer pad on total cost, even when the box price is higher. The lifecycle thinking behind this comparison is documented in the Journal of Cleaner Production and Resources, Conservation and Recycling literature on absorbent hygiene products — the same logic that drives disposable-versus-reusable decisions across care settings.
Vacuum-Compressed Pads: Lower Storage, Same Product
Vacuum compression is a packaging technique that removes air from the bag, reducing the physical volume of a case by roughly a third or more. The pad itself is unchanged — when the bag is opened, the pads expand to normal thickness. For facilities with tight supply closets, vacuum-compressed cases mean more product per shelf and fewer restock trips. CliniEco's vacuum-compressed 60x90 cm pad is built for exactly that storage constraint.
PLA and Sustainable Underpad Options
Conventional underpads end up in the waste stream after one use, and a large facility generates hundreds of thousands of used pads a year. PLA-based topsheets and biodegradable constructions are entering the market as a lower-footprint option. The European Bioplastics association and bioplastics MAGAZINE cover the material properties and certifications in this category, while the degradation behaviour of PLA in different end-of-life environments is examined in the Journal of Polymers and the Environment.
The sustainability question for buyers is the same as for every disposable: does the alternative meet the clinical requirement (dry surface, absorbency, leak resistance) at a defensible cost? Organizations such as Health Care Without Harm and My Green Lab provide frameworks for evaluating single-use product alternatives in healthcare, and the Lancet Planetary Health journal has quantified the broader carbon footprint of healthcare disposables that makes the question worth asking at all.
Quick Facts
- An underpad has three functional layers: topsheet, SAP absorbent core, leak-proof backing
- 30 x 36 inches ≈ 75 x 90 cm — the same pad, two naming conventions
- Absorbency ratings range from light (200–500 mL) to extra-heavy (2,000 mL+)
- Buy on cost per change, not cost per pack
- Vacuum compression cuts storage volume without changing the pad
Frequently Asked Questions
What is the difference between a 30x36 underpad and a 60x90 underpad?
They are the same size in different units: 30 x 36 inches equals about 75 x 90 cm. Suppliers may list either format, so check the inch and centimetre measurements before ordering to avoid receiving a different physical size than expected.
How much fluid can a heavy-absorbency underpad hold?
Heavy-absorbency underpads are typically rated between 1,000 and 2,000 mL. The more useful question is whether the pad keeps the surface dry through a typical void and between scheduled changes — that is what drives skin health and cost per change.
Are underpads the same as adult diapers or briefs?
No. Underpads protect the bed or chair and are changed like linen; briefs are worn on the body and manage incontinence at the source. Many LTC protocols use both — briefs for mobility, underpads for bed surfaces — and they are separate procurement lines. CliniEco supplies adult incontinence briefs and underpads separately so facilities can right-size each.
What does SAP mean on an underpad label?
SAP is superabsorbent polymer, the granule layer in the core that absorbs fluid and locks it in a gel. Pads with a higher-quality SAP core absorb faster and hold more per gram, which is why a 5-layer SAP pad can outperform a heavier-feeling pad without SAP.
Can PLA or biodegradable underpads replace standard pads in LTC?
For tasks the product's absorbency covers, yes — the clinical test is dry skin and no leakage, and PLA-based topsheets can meet it. Verify the absorbency rating and leak-backing performance on the actual product rather than assuming a green label equals equal performance.
How many underpads does a long-term care home go through?
A 100-bed home can use 2,000 to 4,000 underpads per month depending on the resident mix, incontinence rate and protocol. That is why cost per change and vacuum-compressed storage matter — small per-pad differences compound into significant annual spend.
Why do underpads sometimes leak even with a high absorbency rating?
Leaks usually come from three places: a too-small pad that leaves an uncovered zone, a thin backing film that fails under pressure, or a pad left in place past its practical capacity. Match the pad size and rating to the task, and change on the facility's schedule rather than waiting for visible saturation.
What should I look for when comparing underpad suppliers?
Compare the absorbency claim in millilitres, the number of layers, the backing film quality, the topsheet material, and the price per pad. Ask for a sample case and run a real shift test with your staff. CliniEco Medical can send samples of its 30x36 and 60x90 SAP pads for facilities to trial before bulk ordering.
Read the Layers, Then Buy
An underpad is a simple product with three jobs: keep skin dry, keep the surface clean, and keep the budget predictable. Once you read the spec sheet as a layered system — topsheet, SAP core, backing — the adjectives disappear and the numbers do the talking. Size, absorbency, cost per change and storage are the four numbers that matter.
CliniEco Medical supplies heavy-absorbency 30x36 underpads and vacuum-compressed 60x90 SAP pads at wholesale pricing for Canadian LTC homes, clinics and home-care providers. Request underpad samples and bulk pricing for your facility.
Related Reading
Explore more guides in this category:
- Specimen Bags: 95kPa Seal Standards Explained for Canadian Labs
- Procuring Medical Supplies in Alberta: Urban Consolidation and Rural Buffer Planning
- PLA Eco-Friendly Shoe Covers: Sustainable Options in Canada
0 comments