Do not use preservative. Preservatives used for routine analysis may contain mercuric oxide (i.e., Stabilur), which interferes with all metal testing. If both urinalysis and metal testing are ordered, please submit a separate urine specimen (containing no a
Sampling time is during shift or at the end of shift at the end of the work week for industrial exposure monitoring. For metals with multiphase elimination, the timing is given in relation to the work day exposure (shift) as well as to the work week exposure.