A method for determining heavy metal loading in a subject includes collecting a saliva sample from the subject containing a concentration of a heavy metal. The saliva sample is subjected to inductively coupled plasma mass spectrometry to yield a heavy metal loading measurement for the subject. The saliva sample is readily collected on a substrate absorbing a preselected amount of saliva such as filter paper. As the amount of saliva necessary to saturate a given volume of substrate is known, the volume of saliva within a substrate is also known. The resulting heavy metal loading measurement is readily correlated with a blood level for the heavy metal in the subject.