In the past decade or so, with the rise of glove use for most aspects of healthcare delivery, workers have become increasingly interested in glove materials and increasingly concerned about the potential for adverse reactions to certain types of gloves. Administrators are concerned with economy. Managers and staff are concerned with comfort and protection from bloodborne pathogens. Manufacturers are responding by improving latex gloves and developing non-latex alternatives, but along with the greater choice offered to you comes the responsibility of staying informed about your options. What are tensile strength, crosslinking, and memory? Is low-powder the way to go when selecting latex gloves? Here you'll find answers to those questions and learn what the latest glove materials can offer you and your staff.

PROPERTIES OF GLOVES
1) Economy
Let's start here, as many managers have serious concerns regarding cost. The word from glove experts, manufacturers, and managers is that the least expensive glove is not always the most economical, and the superior qualities that some higher-priced products possess might be useless for certain tasks. The key to a cost-effective approach, in other words, is to match the glove material to the task at hand. Vinyl, for example, doesn't offer superior barrier protection or the best comfort in a variety of situations, but it does offer solid skin protection during short procedures not involving body fluids, and the cost is low. On the other hand, the cost of relatively expensive synthetic gloves, which lack protein allergens and many irritants, must be weighed against the cost of managing latex allergy and contact dermatitis and may be worth it to you, particularly when you're considering gloves for long-wear barrier protection. Denise Korniewicz, DNSc, RN, a noted researcher of medical-glove issues and professor at the University of Maryland, says, "Cost is so often the bottom line in making these decisions. My thought is that if managers could know a little bit about the properties of gloves, then they wouldn't decide based on cost only." Many experts agree that barrier effectiveness is the most important consideration, with allergen content following close behind.

2) Barrier protection
Healthcare workers look to gloves for reliable two-way protection from cross-contamination, and away from stress and as long as they aren't punctured by sharps, most medical gloves provide such protection. But the wear and tear of instruments is a reality, and gloves can differ significantly in the amount of protection they provide. Under-standing glove terminology will help you ask your suppliers the right questions, so you can choose the right gloves for your needs.

Strength and durability
Tensile strength. This is a measure of the force required to break the glove, described in pounds per square inch (psi). Tensile strength is central to the durability of a glove and related to resistance to abrasion, tears and punctures. Latex possesses excellent tensile strength, at 3000 psi or better. Vinyl is considered relatively weak, with tensile strength that typically falls below 2000 psi. The American Society for Testing and Materials recommends that tensile strength for surgical gloves be 3500 psi.

Abrasion and puncture resistance. Lack of vulnerability to pressure.

Non-permeability. Ability to prevent passage of solutions, and infectious and toxic materials.

Elasticity. The ability of a material to spring back to its original size, shape and position after being stretched, flexed, or squeezed. A related quality is "memory," which describes "recovery," or how often or quickly glove film will return to its original shape and adapt to the wearer's hand.

Elongation. Arguably a facet of elasticity, this is the measure of how far a glove can stretch before it breaks; this limit is quantified as the percentage of its length that the material can be stretched without breaking. For example, an elongation limit of 600 percent means that a given material can be stretched to six times its original size without breaking.

Crosslinking. A chemically bonded structure wherein individual molecules of the glove film are linked together, providing a continuous interlocked structure with high-level elasticity and strength. Films that are not crosslinked, or poorly crosslinked, tend to easily develop molecular-level holes as well as visible ones.

Chemical resistance
Although not the most important quality for the kind of barrier needed in healthcare, this is an important consideration in clinical settings in which workers occasionally handle caustics, harsh detergents, and cytotoxic drugs.

3) Allergen content
Latex proteins are the most notorious allergen in healthcare, but not the only one glove wearers need to consider. Curing agents and other residual chemicals used in the glove-making process may cause reactions in individuals, though these incidents are seemingly unusual, difficult to trace, and by and large, not yet studied . It is important to note that reaction to an irritant does not necessarily represent an allergy, as is often thought.

Proteins. Lower levels of the latex proteins that cause latex allergy are believed to reduce the potential for latex sensitization. The US Food and Drug Administration specifies that protein levels should be measured using the modified Lowry method for total protein content; the unit of measure in this assay is micrograms per gram. Manufacturers cannot make protein-level claims regarding their products without the FDA's permission. If the FDA agrees that a given protein content has been proven, and a manufacturer has demonstrated that its glove consistently falls below that specific level of protein, the FDA will allow the company to print its maximum protein content on packaging and promotional materials.

Chemicals. These are used to accelerate vulcanization, provide resistance to oxidation, and stabilize compounds, and include thiurams, carbamates, antiozonates, antioxidants, and preservatives. These additives are usually used up in the manufacturing process or transformed to become part of the glove film. Different manufacturers use different chemical combinations and most wash their gloves thoroughly to minimize potentially allergenic or irritating chemicals in them. Allergic individuals may suffer a Type IV delayed reaction to such chemicals; managers or the individuals can investigate causative agents and glove alternatives by trial and error or by questioning the manufacturer.

Powders. Used to "detackify" gloves, powders are not usually allergens in themselves, but they bind with the latex proteins that sometimes cause allergy. Powders shed from gloves, causing the proteins to be inhaled and come into contact with tissue other than that on the hand. Also, in and of themselves??on non-latex and latex gloves??powders can cause irritation or dry skin, again, a situation often confused with an allergic reaction. Keep in mind that disinfectants, soaps, and insufficient hand rinsing can cause skin irritations that may be blamed on gloves.

Glove buyers interested in reducing exposure to allergens or irritants may choose from powder-free or low-powder gloves. Experts and the National Institute of Occupational Safety and Health suggest switching to powder-free gloves rather than low-powder, as there are no regulations or guidelines defining a "low-powder" glove. Interestingly, "powder-free" does not mean powderless, and actually means, by FDA-guidance standards, "no more than 2 mg trace powder per glove." Residual or trace powder is left on gloves when powder is used in the manufacturing process to facilitate easy donning, no matter the low levels used or what the maker's cleaning methods are.

4) Fit and comfort
These are very important qualities, considering the exacting kinds of work done in healthcare and the amount of time that workers wear gloves.

Modulus. Kok-kee Hon is chairman of D11.40, a subcommittee of Consumer Rubber Products at American Society for Testing and Materials. He explains that modulus is the amount of pressure that the stretched material exerts on the hand, referring at different times to the force required to reach a certain elongation, the amount of force required to move the hand in the glove, or "in short, how stiff the material is." Two gloves may be identical in terms of dimension, but one may have a very high modulus, making it (feel) very tight, whereas the other may have a very low modulus, making it feel baggy. A somewhat low modulus is usually desired??comfortable and easy to stretch. This property is particularly important regarding surgical gloves: The higher the modulus, the quicker the hand fatigue. Mr. Hon says that finding this quality is not something you have to be very concerned with??ASTM makes a recommendation for maximum modulus level, and medical gloves on the market tend to be in line with this standard.

Elasticity. Excellent elasticity, or ability to retain shape, is desired for comfort and saving time. The more amenable the glove is to the shape of the wearer's hand, the more quickly he or she can comfortably get down to business.

CONSIDERING GLOVE MATERIALS
Issues abound. Mr. Hon suggests being a tad wary of some of the qualities that manufacturers tout, such as greater puncture resistance, or even puncture resistance itself. Though a manufacturer's claims for this may be true when a given glove is compared with or tested against another, the differences may hardly matter. "What in gloves is puncture resistant against a needle? Nothing is. That's why they're creating retractable needle devices," Mr. Hon says.

Dr. Korniewicz, who says that durability and barrier protection in the clinical setting are what you need to focus on first and second, explains that there is a fine line between those two qualities; they are related, not the same. "For example," Dr. Korniewicz says, "vinyl is very durable, until it is made into a glove, or punctured. The permeability and barrier qualities are not good." More than anything, she says, remember that glove quality may change from manufacturer to manufacturer, potentially affecting your choice of material from manufacturer to manufacturer. "The quality that the manufacturer puts out is, to me, the really important factor," says Dr. Korniewicz.

Natural rubber latex. NRL is made from aqueous fluid collected from the tree Hevea brasiliensis, which is grown primarily in Southeast Asia. A gold standard as far as a useful mix of properties goes, latex gloves offer excellent strength, elasticity, and comfort, and are relatively inexpensive. Elongation limit tends to be about 750 percent. "Still the best barrier protection out there," says Dr. Korniewicz, who does feel that managers should "look at allergen content." She suggests considering low-protein latex gloves. What of the powder issue? The FDA, other federal, and state agencies have received requests over the past three years to ban the use of glove powder. Dr. Korniewicz says that the case for NRL manufacturers creating truly powder-free gloves is warranted, if for no other reason than it's possible. "There are alternatives to powder [for prevention of glove material sticking], so why don't we use them instead? Powder is an irritant as well as the vector of the protein that causes latex allergy. The answer is to eliminate powder and have a lower protein amount," she says.

The most common alternative to dusting powder for NRL, says the FDA, is use of chlorination in the manufacturing process. According to the FDA Web site, "Chlorine reacts with the natural rubber latex surface to reduce the natural tackiness...extra washing performed during the chlorination process provides an added benefit by also greatly reducing the level of soluble natural latex proteins." The site goes on to note, though, that chlorination affects some of the mechanical and physical properties of latex. (See sidebar.) Powder-free latex gloves, like powder-free gloves in general, are more expensive than powdered.