Band neutrophils are the immature form of a white blood cell found in our bodies. All white blood cells act as a defense mechanism against stress and infection. An unusually high level of band neutrophils typically indicates the presence of a bacterial infection or inflammation of tissue. 

Hair may be used to evaluate exposure to barium (Ba). Exogenous contamination has been observed from bath water containing Ba. Elevated levels of hair Ba are often observed as a result of exposure to Ba for diagnostic medical tests.

Urinary barium (Ba) provides an indication of recent or ongoing exposure to the toxic metal, and endogenous detoxification to a lesser extent. The main dietary sources of Ba include milk, flour, potatoes and some nuts and nut butters. Brazil nuts naturally contain high concentrations of Ba (e.g. 1,500 μg/g), and their recent consumption may be transiently associated with clinically insignificant elevations of urinary Ba.

Other sources of exposure to Ba include contaminated water, air or soil. Ba has been used in rodenticides and insecticides, and is used for medical testing (barium “swallow” for imaging). Mining, refining and combustion of coal and oil emit Ba. Mine-tailings and masonry products made from such can be a significant source of Ba to individuals producing or working with them (e.g. reconstruction, demolition).