Provocative testing Provocative urine metal testing for lead and other metals in which chelation agents (eg, dimercaptosuccinic acid, dimercaptopropane sulfonic acid, calcium disodium edetate) are given to the patient and then urinary levels of excreted metals are measured has not been scientifically validated, has no shown benefit, and may be harmful in the assessment and treatment of patients in whom there is concern for metal poisoning.