An Analysis of Gloving Materials
A Self-Study Guide

Properties of Medical Gloves Understanding key attributes that separate quality protective products from inferior ones is extremely important. BARRIER PROTECTION Reliable two-way protection from crosscontamination is the primary reason that medical professionals wear gloves. Barrier effectiveness is defined as the ability of the glove material to withstand rigorous physical, basic bacterial, and viral penetration tests. Testing of new gloves as well as “in-use” testing is necessary to fully evaluate barrier effectiveness. The barrier protection properties of medical gloves can be divided into three (3) categories: Tensile strength. The gloves should not tear when subjected to the pressure of donning or normal use. Abrasion and pinhole (puncture) resistance. The gloves should have no holes through which materials can pass and should be resistant to the formation of holes by puncture or abrasion. Permeability. The gloves should prevent the passage of solutions (typically water-based) and the infectious or toxic materials contained therein. In short, medical gloves must provide a continuous and durable layer of material between the clinician’s hand and the patient’s bodily fluids or tissue specimens. This layer should be flexible, free from holes, breaches, and cracks, and strong enough to prevent breakage during normal use. ALLERGEN CONTENT Allergen content most often refers to the amount of allergenic proteins found in a glove. Lower levels of protein allergens are thought to reduce the potential for sensitization. Protein content is measured using a variety of different assays. However, a great deal of controversy has developed over which assay is the most sensitive, accurate, comprehensive, and appropriate for measuring latex protein allergens. To create a common test by which all gloves can be compared, the U.S. Food and Drug Administration (FDA) has specified that protein levels should be measured using the Modified Lowry Assay for total protein content (ASTM D-5712). The unit of measure for protein content in this assay is micrograms per gram (µg/g). Manufacturers cannot make claims of specific protein levels without the FDA’s permission. Before making such claims, manufacturers must submit production data to the FDA for review. Permission to make protein claims is given to those manufacturers that can demonstrate that their glove consistently falls below a specific level of protein (50µg/g or less). If the FDA agrees that the claimed protein content has been adequately proven, the manufacturer may print their maximum protein content on packaging and promotional materials. Latex proteins are not the only allergens glove wearers need to consider. Glove manufacturing requires the addition of a variety of chemicals to the glove film. These chemicals serve, for example, to accelerate the vulcanization process, stabilize the compounds, and provide resistance to oxidation. Each of these additives serves a critical purpose in producing a functional and economical medical glove. In most cases, these additives are either used up in the manufacturing process or are transformed to become an integral part of the molecular structure of the film. Most manufacturers also leach (wash) their products thoroughly to minimize potentially irritating or allergenic residual chemicals in the final product. Despite these efforts, some individuals may have reactions to residual chemicals in the glove film and therefore may need to further explore the additives used by various manufacturers when selecting a glove. Powder content is another issue that affects the allergenicity of gloves. It is believed that latex allergens on the glove surface bind with glove powders. These powders then find their way into the air when the glove is removed from the box/pack or from the hands. Simply switching to a “low-powder” glove is not the answer. In many cases, the powder content of a glove with a “low-powder” claim is no different from powdered gloves that do not carry this claim. Powder-free gloves are recommended to reduce allergen exposure and minimize production of airborne allergens. STRENGTH AND DURABILITY Essentially, strength and durability are additional measures of barrier protection. Durability, including resistance to abrasion, punctures, and tears, is related to the tensile strength of the glove material. Tensile strength is a measure of how much force is required to break the glove, measured in pounds per square inch (psi). Tensile strength is an important measure of barrier protection, in that a glove that breaks easily does not provide effective barrier protection. ELASTICITY Elasticity is the ability of a material to spring back to its original size, shape, or position after being stretched, squeezed, flexed, or expanded. Elongation, on the other hand, is a measure of how far a glove film can stretch before it breaks. A material’s elongation limit is quantified as the percentage of its length the material can be stretched without breaking. For example, an elongation limit of 500% means the material can be stretched to 5 times its original length before breaking. Elongation can be considered another measure of barrier protection, because gloves are routinely stretched during donning and use, and they must be able to withstand this stretching without breaking or leaking. CROSS-LINKING Cross-linking refers to the chemical bonding structure of the glove film. Cross-linked films tend to be stronger than films that are not cross-linked. The individual molecules are linked to one another and provide a continuous interlocked structure with excellent elasticity and strength. Films that are poorly cross-linked tend to develop holes and breaches, both visible and at the molecular level, when flexed or stretched during donning and normal use. PUNCTURE RESISTANCE Punctures breach the barrier that medical gloves provide. FDA guidelines permit detention or seizure of specific surgical and examination glove lots that exceed certain minimum rates of defects (leaks, tears, mold, embedded foreign objects, etc.). This standard ensures that the majority of medical gloves are intact before use in a clinical setting. FIT AND COMFORT Fit and comfort are important attributes to consider, given the amount of time healthcare personnel spend wearing gloves throughout the workday. Gloves made of different films may fit and feel differently since the physical attributes of the films, such as elasticity and modulus, may vary considerably. Modulus refers to the amount of pressure the stretched film exerts on the hand. In other words, it reflects the force required to reach a certain elongation, the stiffness of the material, or the amount of force required to move the hand in the glove. A glove with a very high modulus will feel very tight, while a glove with an excessively low modulus will feel baggy, even though the two gloves may be dimensionally identical. A glove with a low modulus is comfortable and easy to stretch, while a glove with a high modulus requires more work to stretch, resulting in more rapid fatigue to the hand of the user. Surgical gloves fit more comfortably than ambidextrous gloves because they are hand-specific (left/right). Surgical gloves are produced on ergonomically designed formers with the thumb rotated slightly forward to more closely resemble the human hand. They are typically offered in different sizes (5.5-9), whereas ambidextrous gloves are available in extra-small through extra-large sizes. CHEMICAL RESISTANCE Although chemical resistance is not the primary purpose of medical gloves, clinicians handle harsh chemicals in many situations. The chemical resistance of various glove films ranges from poor to excellent. Before handling dangerous chemicals, be sure to select a suitable glove. ECONOMY Although latex and vinyl gloves are relatively inexpensive, latex-free products (e.g., nitrile, neoprene, polyisoprene, and other specialized polymers) can be costly. Powder-free gloves are slightly more expensive than powdered gloves, due to the extra processing they undergo to render them powder-free. It is important to recognize that a less expensive glove is not always the most economical. Conversely, the most expensive glove is not always of the highest quality. The key to cost-effectiveness in glove purchasing is to match the glove material to the task at hand. Significant cost savings can often be realized by participating in a glove audit to identify major glove usage patterns and recommend appropriate gloves for specific tasks. Obviously, sterile surgical gloves are not needed to clean bedpans; at the same time, surgeons cannot perform surgical procedures wearing laboratory gloves. Selective glove choice can save money— not by recommending the lowest-cost product—but by appropriately matching the glove to the task. In the long term, the higher cost of purchasing powder-free, less allergenic gloves must be weighed against the cost of treating allergic reactions. Managing latex allergy has a number of associated costs, which can be significant. Material is an important determinant of glove barrier effectiveness and other aspects of glove performance. It pays to understand the differences between gloving materials, as there is a wide variety of gloves available to healthcare workers. The mix of glove materials used by medical professionals is changing as healthcare professionals become more educated about the risks associated with low-cost, high-allergen, powdered latex gloves. Current purchasing data demonstrates that an increasing number of healthcare professionals will switch to powder-free latex or latex-free gloves to reduce their exposure to allergens and thereby reduce the risk of sensitization for themselves, their coworkers, and their patients.

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