According to Goldman and Woolf (2012)
“Sometimes chelation therapy is recommended based on the results of non-standard laboratory tests for multiple elements performed on samples of hair, blood, urine or other specimens. Such testing may show levels of chemicals above the laboratory’s reference range, but these are not necessarily levels that cause health problems. Sometimes a laboratory test known as “provocation testing” is used which involves giving a chelation medicine to "provoke" and measure the excretion of toxicants. This type of testing is not recommended. It does not reliably show high or toxic levels in the body nor prove the benefit of taking chelation therapy. It is also misleading to compare test results after taking “provoking” chelation medicine to test results from the reference population who have not taken the medicine. In standard medical practice, chelation therapy is given after carefully considering the results of standard laboratory tests, clinical factors, and scientific evidence.”