What is a transparent PU film dressing and what does it do?

A transparent polyurethane (PU) film dressing is a thin, self-adhesive semi-permeable membrane made from transparent polyurethane film coated with a hypoallergenic acrylic adhesive. It serves three functions simultaneously: (1) it creates a bacterial and waterproof barrier protecting the wound or insertion site from external contamination; (2) it allows water vapor to pass through (moisture vapor transmission) preventing moisture accumulation that would cause maceration; and (3) it is transparent, allowing continuous visual inspection of the wound or catheter site without dressing removal. It is indicated for IV catheter securement, low or no exudate wounds, protection of at-risk intact skin, and securing of other dressings as a secondary retention layer. It is not suitable for moderate to heavily exuding wounds as the film has no absorption capacity.

What is MVTR and why does it matter for transparent film dressings?

MVTR (Moisture Vapor Transmission Rate) is the rate at which water vapor passes through the film dressing, expressed in g/m²/24h. For transparent film dressings, MVTR is the critical performance parameter because the film has no absorbent capacity — it must allow sufficient water vapor to escape to prevent moisture accumulation under the dressing, which would cause maceration and reduce adhesion. However, published research has demonstrated that MVTR values for the same dressing can vary dramatically depending on the test method used: the EN 13726 upright method (dressing in contact with vapor) and the inverted method (dressing in contact with liquid) can produce values differing by more than tenfold for the same product. Procurement managers comparing MVTR values across suppliers must confirm that the same test method was used, otherwise the comparison is meaningless.

What is the difference between upright and inverted MVTR test methods?

EN 13726 defines two MVTR test methods for film dressings using a Paddington cup: (1) Upright method — the dressing is tested in contact with water vapor (not liquid water). EN 13726 specifies this method as appropriate for thin film dressings, such as transparent IV and wound dressings. Results represent the dressing's performance when in contact with wound vapor, as occurs at IV sites and low-exudate wounds. (2) Inverted method — the dressing is tested in contact with liquid water. This method simulates conditions more relevant to highly exuding wounds. Published research testing seven IV dressings found upright method MVTR values ranging from 773 to 2,838 g/m²/day, while inverted method values for the same products ranged from 845 to 30,530 g/m²/day (Bainbridge et al., 2021). For IV dressing procurement, the upright method is more clinically relevant. Always confirm which test method was used when comparing MVTR values across suppliers.

For which wounds are transparent film dressings suitable and not suitable?

Suitable applications: IV catheter and PICC line insertion sites; post-operative wounds with no or minimal exudate; superficial wounds and abrasions with no or minimal exudate; skin graft donor sites in the early healing phase; protection of at-risk intact skin (pressure injury prevention over bony prominences); secondary retention dressing over other primary dressings; radiation dermatitis with no exudate. Not suitable: wounds with moderate to heavy exudate — the film has no absorbency, and exudate will accumulate under the dressing causing maceration and dressing failure; infected wounds with active drainage; heavily contaminated wounds. The fundamental limitation of transparent film dressings is zero absorption capacity. Exudate must have somewhere to go, and with a film dressing, it cannot — making exudate management the key clinical selection criterion.

What should a purchase order for transparent film dressings include?

A complete purchase order for transparent film dressings should specify: (1) Application — IV/catheter fixation or wound coverage, as these have different shape and MVTR requirements; (2) Size and shape — standard rectangular sizes for wound coverage, catheter-specific shapes (with or without slit/fenestration for catheter exit site) for IV applications; (3) MVTR — request the actual value tested by the upright method per EN 13726; (4) Adhesive type — standard acrylic or hypoallergenic/reduced-adhesive for sensitive skin; (5) Frame/application system — frame-style delivery systems aid single-handed application and reduce handling errors; (6) Sterile — confirm individual sterile packaging; (7) CE marking under EU MDR 2017/745. Omitting the application type is the most common specification error — IV dressings and wound film dressings share the same material but differ in shape, MVTR design, and adhesive border configuration.

Kingphar Medical Group

New's

20/4 2026

Transparent PU Film Dressing: Specifications, Uses & Procurement Guide 2026

Wound Care · Film Dressing Guide

Transparent PU Film
Dressing: Specifications
& Procurement Guide 2026

Transparent PU film dressings are among the most procured wound care products globally — yet MVTR comparisons between suppliers are frequently misleading because different test methods produce wildly different values for the same product. This guide explains the upright vs inverted MVTR test method problem, covers IV site vs wound coverage applications, specifications, and a procurement checklist.

What transparent film dressings do MVTR: the critical parameter Upright vs inverted test method IV site vs wound applications Specifications Procurement checklist

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Base material

PU Film

Transparent semi-permeable polyurethane film — waterproof outer surface, vapor-permeable, hypoallergenic acrylic adhesive

Absorption capacity

Zero

Film dressings have no absorbent layer — not suitable for wounds with moderate or heavy exudate

MVTR test range

773–2,838

g/m²/day — range across 7 commercial IV dressings tested by upright method per EN 13726 (Bainbridge et al., 2021)

CE classification

Class Is

Sterile transparent film dressings — EU MDR 2017/745, notified body required for sterility aspect

Transparent polyurethane film dressings were introduced to wound care in the 1970s and remain one of the most widely used dressing types globally — primarily for IV catheter securement, low-exudate wound coverage, and protection of at-risk skin. Their core value proposition is simple: a waterproof, transparent, semi-permeable membrane that protects the wound or insertion site while allowing continuous visual inspection without dressing removal.

For procurement managers, the most important — and most misunderstood — specification is MVTR. Published peer-reviewed research has demonstrated that the same dressing can produce MVTR values differing by more than tenfold depending on which EN 13726 test method is used. This creates significant confusion when comparing supplier datasheets. This guide explains the test method problem in detail and provides practical procurement guidance to avoid specification errors. For related dressing procurement context, see our Foam Dressing Specifications Guide and our Non-Adherent Dressing Types Guide.

Section 01

What Transparent Film Dressings Do — and Don't Do

A transparent PU film dressing is a three-function product: it provides a barrier, it transmits vapor, and it allows visibility. Understanding what it cannot do is equally important for procurement.

Function	How it works	Clinical implication
Bacterial barrier	PU film is impermeable to bacteria and liquid water — external contamination cannot reach the wound or insertion site	Protects IV sites and wounds from environmental contamination; enables showering without dressing change
Moisture vapor transmission	PU film is semi-permeable — water vapor passes through from the wound/skin surface to the external environment	Prevents moisture accumulation under the dressing that would cause maceration and adhesive failure
Visual inspection	Film is transparent — wound bed or catheter insertion site is visible without removing the dressing	Enables early detection of IV site complications (phlebitis, infiltration) and wound changes without dressing disruption
Moist wound environment	Semi-occlusion slows desiccation of the wound surface while transmitting excess vapor	Supports epithelialisation in low-exudate wounds without making the wound wet
❌ Absorption	Film has no absorbent layer — exudate cannot be managed	Not suitable for wounds with any meaningful exudate production — exudate accumulates under the film causing maceration and dressing failure

Zero absorption capacity — the most important limitation

Transparent film dressings have no absorbency. This is not a relative limitation — it is absolute. If a wound produces exudate, the film will trap it underneath, causing maceration of the wound bed and surrounding skin, and the dressing will fail as adhesion breaks down. Film dressings are indicated only for no-exudate or minimal exudate wounds. If in doubt about exudate level, do not specify a film dressing — specify a foam or non-adherent dressing instead.

Section 02

MVTR: The Critical Parameter — and the Test Method Problem

MVTR (Moisture Vapor Transmission Rate) is the rate at which water vapor passes through the film in g/m²/24h. For film dressings, it is the primary performance differentiator — higher MVTR allows more vapor to escape, reducing maceration risk. However, procurement decisions based on MVTR values in supplier datasheets frequently lead to incorrect product selection because of a fundamental test method problem.

The upright vs inverted method problem — verified research

EN 13726 defines two test methods for measuring MVTR of film dressings using a Paddington cup apparatus. Published peer-reviewed research (Bainbridge et al., 2021) tested seven commercially available IV transparent film dressings using both methods and found:

Recommended for IV and wound film dressings

Upright Method (EN 13726 §3.2)

773–2,838 g/m²/day

Film tested in contact with water vapor. EN 13726 specifies this method as appropriate for thin film dressings. Simulates clinical conditions at IV sites and low-exudate wounds where the dressing is in contact with vapor, not liquid water. Research concludes this method is better suited for IV dressing comparison.

Less appropriate for IV dressings

Inverted Method (EN 13726 §3.3)

845–30,530 g/m²/day

Film tested in contact with liquid water. Intended for waterproof dressings in contact with liquid. Produces significantly higher values for the same products — up to tenfold higher than upright method for some dressings. Not representative of IV site or low-exudate wound conditions. Commonly used by manufacturers when marketing "high MVTR" products.

Always ask: which method was used to measure MVTR?

Many supplier datasheets quote MVTR without stating the test method. A product quoted at 10,000 g/m²/day using the inverted method may deliver the same real-world performance as a product quoted at 1,500 g/m²/day using the upright method. The numbers are not comparable across methods. When requesting EN 13726 MVTR data from suppliers, specify "upright method per EN 13726 §3.2" to ensure comparable values. Research also notes that "higher MVTR is better" is an oversimplification — once MVTR is sufficient to prevent moisture accumulation, further increases do not provide additional clinical benefit.

Source: Bainbridge P et al., "Comparing test methods for moisture-vapor transmission rate (MVTR) for vascular access transparent semipermeable dressings," Journal of Vascular Access, 2021. PMC10631281.

Section 03

Two Main Applications: IV Site vs Wound Coverage

Transparent film dressings serve two distinct primary applications with different shape, size, and MVTR requirements. Specifying by application avoids receiving a product designed for one use in the other context.

Parameter	IV catheter / PICC site fixation	Wound coverage
Primary function	Secure catheter in place; protect insertion site; allow visual inspection for complications	Protect low-exudate wound; maintain moist environment; allow wound bed inspection
Shape options	Standard rectangular; with or without window/slit for catheter exit; port-specific shapes	Standard rectangular; oval; sacral; custom wound shapes
Typical sizes	Smaller formats — sized to cover insertion site only (e.g. 6×7 cm, 7×9 cm)	Larger formats — sized to cover wound with border (e.g. 10×12 cm, 15×20 cm)
MVTR requirement	Sufficient to prevent moisture accumulation at IV site — upright method value is relevant	Sufficient to allow low-level vapor transmission from wound surface — comparable requirement
Adhesive considerations	Must maintain adhesion during patient movement, showering, perspiration	Hypoallergenic adhesive important for prolonged skin contact around wound
Application system	Frame-style or tab delivery recommended — catheter hub limits access; single-handed application aids placement	Standard frame or liner removal acceptable
Change frequency	Per clinical protocol for IV site management — typically every 3–7 days or as clinically indicated	As clinically indicated — when dressing integrity compromised, edges lifting, or wound changes

Section 04

Product Specifications

Transparent PU film dressing — specification reference

Film materialTransparent semi-permeable polyurethane (PU) film

AdhesiveHypoallergenic acrylic adhesive — skin-contact side only

Outer surfaceWaterproof — impermeable to liquid water and bacteria

TransparencyFully transparent — wound and insertion site visible without removal

MVTRRequest actual value, upright method per EN 13726 §3.2 — confirm test method used

Absorption capacityNone — primary wound contact layer only for no/minimal exudate wounds

Standard sizesMultiple — specify by application (IV site sizes vs wound coverage sizes)

Application systemFrame-style or tab-release liner — frame-style recommended for IV applications

SterilityIndividually sterile packed — EO (ISO 11135) or gamma (ISO 11137), SAL 10⁻⁶

Latex contentLatex-free — confirm in writing

RegulatoryCE (EU MDR 2017/745 Class Is) · ISO 13485 · FDA registered

Section 05

Clinical Selection: When to Use Transparent Film Dressings

Application	Suitable?	Notes
IV catheter / peripheral cannula site	✓ Primary indication	Standard of care for peripheral IV sites — allows visual inspection; waterproof; secures catheter
PICC / CVC central line site	✓ With appropriate product	Use PICC/CVC-specific sizes and shapes; follow institutional IV care bundle protocols
Post-operative wound (no exudate)	✓ Suitable	Clean, dry surgical incision with no drainage — film allows showering; wound visible without disturbing
Superficial abrasion / minor wound	✓ Suitable	Low or no exudate; film maintains moist environment supporting epithelialisation
Skin graft donor site (early phase)	✓ Suitable (low exudate phase)	Transition to higher-absorbency dressing if exudate increases
At-risk intact skin (pressure injury prevention)	✓ Suitable	Protects bony prominences from friction and shear; transparent allows skin inspection
Securing other primary dressings	✓ Suitable	Secondary layer to hold non-adhesive primary dressings in place
Wound with low-moderate exudate	⚠️ Caution	Exudate may accumulate — monitor closely; consider island dressing (film + absorbent pad) instead
Wound with moderate to heavy exudate	✗ Not suitable	Film has zero absorbency — exudate will accumulate causing maceration and dressing failure
Infected wound with drainage	✗ Not suitable	Film traps drainage; infected wounds require absorbent antimicrobial dressings

Island dressing: the alternative for wounds with light exudate

For wounds with light exudate where a transparent film alone would fail but a full foam dressing would be overspecified, an island wound dressing (transparent PU film with an integrated central absorbent pad) provides a middle option. The absorbent island handles light exudate; the film border seals and secures the dressing. See our Island Wound Dressing product page for this option.

Section 06

Procurement Specification Checklist

Specify application — IV/catheter fixation or wound coverage — these require different sizes and shapes. IV dressings may need catheter-specific configurations; wound coverage dressings need appropriate border sizing. "Transparent film dressing" without application type is underspecified
Request MVTR by the upright method (EN 13726 §3.2) — specify the method, not just the value — ask suppliers to confirm which EN 13726 method produced their quoted MVTR. Upright method values are more clinically relevant for IV and low-exudate wound applications. Do not compare upright and inverted method values against each other
Confirm the film is waterproof (liquid impermeable) — not just vapor permeable — a semi-permeable film allows vapor through but must block liquid water. Request waterproofness test data per EN 13726. This is particularly important for IV sites where the patient may shower or encounter liquid water
Specify application delivery system — frame-style vs tab-release liner — for IV applications, frame-style delivery is strongly preferred as it allows placement around the catheter hub without disturbing it. Tab-release liners are acceptable for wound coverage applications
Confirm hypoallergenic acrylic adhesive and request biocompatibility data — film dressings remain in contact with periwound skin for extended periods. ISO 10993-5 (cytotoxicity) and ISO 10993-10 (sensitization) data should be available from suppliers
Verify CE marking — Class Is for sterile, referencing EU MDR 2017/745 — sterile transparent film dressings require notified body CE certificate. Certificate must reference "Regulation (EU) 2017/745" — MDD 93/42/EEC certificates expired May 2024
For GCC supply — confirm SFDA registration and Arabic labeling capability — transparent film dressings are classified as medical devices in Saudi Arabia and require SFDA registration for institutional supply

Data Sources

Bainbridge P, Browning P, Bernatchez SF, Blaser C, Hitschmann G. "Comparing test methods for moisture-vapor transmission rate (MVTR) for vascular access transparent semipermeable dressings." Journal of Vascular Access, 2021. PMC10631281. MVTR upright range 773–2,838 g/m²/day; inverted range 845–30,530 g/m²/day for seven commercial IV dressings.
EN 13726 (previously EN 13726-2:2002, now consolidated into EN 13726:2023). European Committee for Standardization (CEN). MVTR test methods: upright (§3.2) and inverted (§3.3) Paddington cup methods.

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Kingphar manufactures transparent PU film dressings for IV site fixation and wound coverage — CE-certified under EU MDR 2017/745, EN 13726 MVTR tested, ISO 13485, with SFDA registration support and Arabic labeling for GCC institutional supply.

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