Decoding the claims

National report - Dermatologists can offer patients some guidelines for shopping for sun-protective clothing, says Kathryn Hatch, Ph.D., professor, agricultural and biosystems engineering department, University of Arizona College of Agriculture and Life Sciences, Tucson, Ariz.

Three U.S. voluntary standards for sun-protective clothing are:

Dr. Hatch explains that when a garment label states or implies that the garment is sun-protective, the manufacturer, retailer or certifier is making a claim for sun protection. Consumers should look for:

Labels should also show a UPF value or an SPF value. The number that follows UPF or SPF indicates "how much longer a person can stay in the sun before their skin begins to redden in comparison to the time for that person's uncovered skin to redden under identical exposure conditions," Dr. Hatch says.

The higher the number, the longer a person whose skin is covered with the fabric can stay outdoors in the daytime before their skin will redden.

Finally, consumers should check the labels that state percentage of UVA radiation blocked by the fabric.

"The higher the percentage of UVA blocked, the greater the slowing of premature skin aging that can be caused by sun exposure," Dr. Hatch says.