Disposable underpads — also known as bed pads, nursing pads, or draw sheets — are among the most versatile and widely used consumables in healthcare. They serve a deceptively simple function: place the pad beneath a patient, and it absorbs any liquid discharge while protecting the mattress or surface below. But beneath that straightforward premise lies a product category with significant variation in materials, absorption capacity, sizing, and quality. Choosing the right underpad for your facility's specific needs can improve patient comfort, reduce laundry costs, streamline clinical workflows, and support infection control objectives.
This guide covers everything procurement teams and clinical managers need to know: how underpads are constructed, how to match size and absorption to use case, what quality markers to look for, and how to source them efficiently at scale.
The Multi-Layer Construction of a Quality Underpad
A well-designed disposable underpad is not a single piece of material — it is a carefully engineered multi-layer structure, with each layer performing a specific function:
- Top sheet (surface layer). The layer that contacts the patient. Made from soft, nonwoven fabric — typically spunbond or airlaid nonwoven — it must feel comfortable against skin, resist tearing under patient movement, and allow liquid to pass through rapidly into the absorption layer below. The softness of this layer directly affects patient comfort, particularly for bedridden patients who may rest on the pad for extended periods.
- Absorption core. The heart of the underpad. This layer contains a combination of absorbent fluff pulp and super absorbent polymer (SAP) — a material capable of absorbing and retaining many times its own weight in liquid. The ratio of pulp to SAP, the grammage (weight per square metre) of the core, and the distribution of SAP all affect how much liquid the pad can absorb, how quickly, and how well it retains it under pressure.
- Tissue wrapping layer. A thin tissue paper layer that wraps around the absorption core, preventing SAP and fluff pulp from migrating or shifting during use and ensuring the core maintains its integrity under pressure.
- Bottom sheet (backing layer). The layer that faces the mattress or surface. Made from PE (polyethylene) film or PE-laminated nonwoven, it must be completely waterproof to prevent any liquid from reaching the mattress. A non-slip texture on the underside helps keep the pad in place, particularly on smooth mattress surfaces.
The quality of each layer — and the bond between layers — determines whether an underpad performs reliably in real clinical conditions or fails at a critical moment. Cheaper underpads often skimp on the SAP content, use thinner or lower-quality nonwoven for the top sheet, or use backing films that tear easily under patient weight.
Super Absorbent Polymer (SAP) — The Key to Performance
Super absorbent polymer is the technological differentiator in modern underpads. SAP particles — typically sodium polyacrylate — can absorb 30 to 50 times their own weight in water, and crucially, they retain the absorbed liquid even under pressure. This means that when a patient lies or sits on a pad, the liquid does not squeeze back out to the surface (a problem known as "rewet").
Not all SAP is equal. Higher-quality SAP offers:
- Faster absorption rate. Liquid is drawn into the pad more quickly, reducing the time the surface stays wet.
- Higher absorption under pressure. Retains more liquid even when compressed by patient body weight.
- Better gel strength. The absorbed liquid forms a firmer gel that resists breaking down and leaking at the edges of the pad.
- Lower rewet. Less moisture returns to the surface, keeping the patient's skin drier and reducing the risk of skin breakdown.
When comparing underpads from different suppliers, ask about the SAP content and type. A pad with higher SAP content (typically 10–20% of the core by weight) will generally outperform a pad with lower SAP, even if the total grammage is similar.
Size Selection — Matching Pad to Use Case
Disposable underpads come in a range of sizes, and selecting the right size is critical for both effectiveness and cost efficiency:
Small (40 × 60 cm / 16" × 24")
The most common size for general nursing use. Suitable for wheelchair seating, examination table coverage, protecting chair seats, and spot protection on beds for light incontinence or wound drainage. Small pads are the workhorse of most facilities — easy to handle, quick to change, and cost-effective for high-frequency use.
Medium (60 × 60 cm / 24" × 24")
A square format that provides broader coverage than the small size. Often used for larger wheelchair users, as changing mats for infant care, and for covering wider surfaces such as physiotherapy tables. The square shape makes it easier to orient the pad correctly in busy clinical environments where staff may not have time to check dimensions.
Large (60 × 90 cm / 24" × 36")
The standard bed-size underpad for moderate to heavy incontinence. Covers the area from the patient's shoulders to below the hips on a standard hospital bed, providing comprehensive protection. This is the most commonly used size for bedridden patients in hospital wards, nursing homes, and long-term care facilities. It is also widely used for post-operative patient recovery, where wound drainage may require a larger protected area.
Extra Large (90 × 150 cm / 36" × 60") and Beyond
Full-bed coverage for bariatric patients or situations where maximum surface protection is needed. Used in maternity wards, operating theatre preparation areas, and emergency department gurneys. Larger pads are also used in veterinary settings for large animals and in pet care facilities.
A common procurement mistake is standardising on a single size to simplify ordering. In practice, most facilities benefit from carrying at least two sizes — a small pad for spot protection and a large pad for bed use — because using an oversized pad where a small one would suffice is wasteful, while using an undersized pad risks insufficient coverage and mattress contamination.
Absorption Capacity Grading
Underpads are typically classified by their absorption capacity, though the grading system is not universal across suppliers. A practical way to think about absorption levels:
- Light duty (200–400 ml). Suitable for wound drainage, light urinary incontinence, examination table coverage, and procedural use. These pads are thinner and more comfortable for patients who need only occasional protection.
- Medium duty (400–800 ml). The standard for hospital ward and nursing home use. Handles moderate incontinence episodes, post-operative drainage, and general bed protection. This is the most commonly specified absorption level for routine patient care.
- Heavy duty (800–1500 ml). Designed for heavy incontinence, overnight use, and situations where pad changes may be less frequent. The higher SAP content and thicker core provide extended protection and are particularly valuable in long-term care settings where staffing ratios may limit how often pads can be changed.
- Extra heavy duty (1500 ml+). For the most demanding applications — bariatric care, maternity, and operating theatre use. These pads use the highest SAP content and are often reinforced with additional tissue layers to prevent core breakdown under sustained pressure.
"We used to buy the cheapest underpads we could find, thinking a pad is a pad. After switching to medium-duty pads with higher SAP content, our mattress replacement costs dropped by 40% because the cheaper pads were letting liquid through to the mattress at the edges. The slightly higher pad cost was more than offset by the mattress savings — not to mention fewer patient complaints about wet bedding." — Ward Manager, Provincial Hospital, Jiangsu
Edge Sealing and Leak Prevention
One of the most common failure modes in disposable underpads is edge leakage. When liquid reaches the edge of the pad and wicks over onto the mattress, the pad has effectively failed, regardless of its central absorption capacity. Quality underpads address this through:
- Heat-pressed edge seals. The four edges of the pad are sealed with heat and pressure, creating a barrier that prevents liquid from escaping laterally. Cheaper pads may have only glue-based edge bonding, which can fail under pressure or when the pad shifts.
- Channel design. Some premium underpads feature embossed channels or grooves in the surface that direct liquid away from the edges and toward the centre of the pad, where the SAP concentration is highest. This significantly reduces edge leakage even when the pad is nearly saturated.
- Non-slip backing texture. A textured PE backing helps keep the pad in place on smooth mattress surfaces, reducing the risk that the pad will shift and expose uncovered areas of the mattress.
When evaluating underpads, the edge seal quality is one of the easiest things to test: place the pad on a flat surface, pour a measured amount of water onto one edge, and observe whether the liquid stays contained or wicks over the edge. This simple test reveals more about real-world performance than grammage specifications alone.
Use Cases Across Healthcare Settings
Hospital Wards
In a typical acute-care ward, underpads are used for incontinence management, post-operative wound drainage protection, and as a barrier during procedures that may generate fluid spillage. A 300-bed hospital may consume 500–1,500 underpads per day depending on patient acuity and care protocols. The large (60 × 90 cm) size in medium-duty absorption is the standard specification for most ward applications.
Nursing Homes and Long-Term Care
Residential care facilities use underpads continuously for residents with chronic incontinence. Here, the priority is often extended protection — pads that can last through the night without leaking, reducing the need for disruptive overnight changes. Heavy-duty underpads with higher SAP content are particularly valuable in this setting, as they improve both resident comfort and staff workload.
Operating Theatres and Procedure Rooms
Underpads are used in surgical and procedural settings to protect operating tables, absorb irrigation fluids, and manage blood and other bodily fluids during procedures. In these applications, the pad must withstand significant fluid volumes without leaking, and the top sheet must resist tearing when instruments or equipment are placed on it. Extra-heavy-duty pads with reinforced edges are typically specified for theatre use.
Maternity Wards
Maternity settings use large and extra-large underpads during labour and delivery to manage amniotic fluid, blood, and other fluids. The pads must be comfortable for the mother, highly absorbent, and large enough to provide comprehensive coverage. After delivery, underpads continue to be used for postpartum monitoring and newborn care.
Home Care and Personal Use
The growing home care market — driven by ageing populations and the preference for ageing-in-place — represents a significant and growing segment of underpad demand. Home users typically prefer smaller packs with clear usage instructions, and the pads must be easy to handle for family caregivers who may not have clinical training. Softness and odour control are particularly important in home settings, where the psychological comfort of the patient matters as much as the physical protection.
Veterinary and Pet Care
Veterinary clinics, animal shelters, and pet owners use underpads for surgical recovery, incontinence management, and cage/kennel lining. The specifications are similar to human healthcare use, though packaging and marketing differ. Pads for veterinary use may come in larger sizes to accommodate larger animals, and the top sheet may need to be more puncture-resistant to withstand animal claws.
Quality Indicators and Testing Standards
When sourcing underpads, look for the following quality indicators:
- Grammage (g/m²). The total weight per square metre of the pad, typically ranging from 400 g/m² for light-duty pads to over 1,000 g/m² for heavy-duty pads. Higher grammage generally indicates more absorption material, but the SAP-to-pulp ratio matters as much as total weight.
- Absorption capacity (ml). The volume of liquid the pad can absorb and retain. Reputable suppliers will provide tested absorption figures, measured using standard laboratory methods (e.g., EDTA synthetic urine solution under defined pressure).
- Rewet value (g). The amount of liquid that returns to the surface under pressure after absorption. Lower is better — a good underpad should have a rewet value of less than 5 grams even at near-saturation.
- Tensile strength. The resistance of the pad to tearing, particularly important for pads used with active or restless patients who may pull or shift the pad during use.
- ISO 13485 certification. For underpads marketed for medical use, the manufacturer should operate under an ISO 13485 certified quality management system, ensuring consistent production quality, traceability, and regulatory compliance.
- Skin safety. The top sheet material should be tested for skin irritation and sensitisation, particularly for pads intended for prolonged skin contact in incontinence care.
Procurement Strategy — Balancing Cost and Performance
Underpads are a high-volume consumable, and even small per-unit cost differences translate into significant annual spend. However, the cheapest option is rarely the most cost-effective when total cost of ownership is considered:
- Calculate total cost per protected surface-day. A cheaper pad that leaks and requires mattress cleaning or replacement is more expensive in total than a slightly pricier pad that performs reliably. Factor in mattress replacement costs, laundry costs for soiled linens, and staff time for additional changes when comparing options.
- Right-size the specification. Don't overspecify absorption capacity for applications where light-duty pads would suffice — but don't underspecify either. Match the pad to the actual clinical need for each ward or use case, and consider carrying multiple grades to optimise cost across the facility.
- Order in bulk for volume pricing. Most manufacturers offer tiered pricing with significant savings at full-carton and full-pallet levels. For facilities with consistent monthly usage, quarterly or semi-annual bulk orders are typically more economical than monthly small orders.
- Request samples before committing. Always test samples under real clinical conditions before placing a large order. The edge seal test described above is a quick, practical way to compare options side by side.
- Consider packaging configuration. Underpads are typically packed 10–30 per bag, with multiple bags per carton. Choose a pack size that matches your facility's change frequency and storage capacity — smaller packs are easier to handle and store at the point of care, while larger packs reduce per-unit packaging cost.
- Custom branding and OEM. For distributors and large healthcare groups, custom-branded packaging with your own label and product specifications is available from most manufacturers. This allows you to build your own product line while leveraging established manufacturing quality.
Environmental Considerations
Disposable underpads, like all single-use medical consumables, generate waste. However, several factors are helping to reduce their environmental footprint:
- Optimised absorption means fewer pad changes. Higher-quality pads with better SAP content need to be changed less frequently, reducing the total number of pads used per patient-day.
- Reduced laundry burden. Effective underpads protect mattresses and bed linens from soiling, which reduces the volume of laundry that needs to be washed — a significant energy and water saving compared to the impact of the pads themselves.
- Material choices. The nonwoven top sheet and PE backing are both thermoplastic materials that are theoretically recyclable, though current healthcare waste protocols typically direct all used underpads to general or clinical waste streams. Some manufacturers are exploring bio-based nonwoven materials and more easily separable layer constructions to improve end-of-life recyclability.
- Reusable alternatives. For facilities looking to reduce disposable waste, washable underpads with waterproof TPU backing are an option for certain applications. These can be washed and reused 200–300 times, though they require laundry infrastructure and are less suitable for heavy incontinence or single-patient-use scenarios.
The most effective environmental strategy is usually a hybrid approach: use disposable underpads for high-risk applications where leakage must be absolutely prevented (surgery, heavy incontinence, infectious patients) and reusable pads for lower-risk applications (examination table coverage, light drainage, procedural use).
Conclusion
Disposable underpads are one of those healthcare products that seem simple until you need them to perform reliably — at which point the quality differences between products become very apparent. A good underpad absorbs quickly, retains liquid under pressure, stays in place, and keeps the patient's skin dry. A poor underpad leaks, shifts, tears, or allows moisture to return to the surface, creating additional work for staff and discomfort for patients.
For procurement teams, the key is to match the underpad specification — size, absorption capacity, SAP content, and edge seal quality — to the specific clinical application, and to source from manufacturers who can provide consistent quality, reliable supply, and the documentation needed for regulatory compliance. Getting this right reduces total cost of care, improves patient comfort, and supports the broader infection control and hygiene objectives of the facility.
Newrise Medical manufactures disposable underpads in multiple sizes (40×60 cm, 60×60 cm, 60×90 cm, 90×150 cm) and absorption grades, with SAP cores, PE backing, and heat-pressed edge seals. Produced in our ISO 13485 certified facility in Changzhou, China, with OEM and custom packaging options available. Contact us for samples and pricing →