Which test is most accurate for body composition?

Hydrostatic weighing is still touted the “gold standard” in body composition assessment, but newer technology such as the Bod Pod and DEXA scan are becoming increasingly favored. 

Hydrostatic weighing is considered the gold standard as mentioned, but this tends to be a little impractical in a gym setting. Other options are to use a handheld bioelectric impedance device (BIA), such as an Omoron, or skinfold caliper that measure subcutaneaous fat by pinching certain areas of the body. While BIA devices can give you an ok measurement to work with, they can vary drastically depending on how much you have eaten or drank before testing.  A qualified and experienced professional will give you much more accurate and consistent readings using the skinfold calipers.  This is the preferred method of testing in a gym setting where we may not have access to larger or more costly devices like hydrostatic weighing, Bod Pod, and DEXA scan.