title: Clinical evaluation of a lead mobilization test using the chelating agent dimercaptosuccinic acid.
abstract: BACKGROUND
  The lead mobilization test reflects the mobilizable and likely toxicologically active fraction of the lead body burden. We propose a safe and convenient protocol for this test, to assess concomitant copper and zinc excretion and to determine the size of the chelatable lead pool in nonoccupationally exposed adults.
  
  
  METHODS
  The study population included 80 white adults: 40 controls [median blood lead concentration (PbB), 25 microg/L] and 40 lead-exposed individuals (315 microg/L). After collection of 4- and 24-h baseline urine specimens and a blood sample, dimercaptosuccinic acid (DMSA) was administered orally (1 g), and additional 4- and 24-h urine specimens were obtained. Determinants of the chelatable urinary lead (DMSA-PbU) were traced by linear regression analysis.
  
  
  RESULTS
  Urinary DMSA and lead excretion peaked within 2-3 h after DMSA administration. The amounts of DMSA, lead, copper, and zinc recovered in the 4-h urinary collections were highly correlated with those in 24-h collections (r = 0.857, 0.859, 0.958, and 0.757, respectively). At PbB concentrations >300 microg/L, the relationship between DMSA-PbU and PbB showed a steep increase and a widespread dispersion of DMSA-PbU around the regression line. After DMSA, copper and zinc excretion rates were increased up to 91- and 33-fold, respectively. No side effects were reported after DMSA.
  
  
  CONCLUSIONS
  Determination of DMSA-PbU in a 4-h collection after DMSA is convenient, apparently safe, and inexpensive. An upper reference limit value of 22 microg/4 h is proposed for Belgian reference individuals. The diagnostic value of DMSA-PbU is likely to be contributive for PbB >300 microg/L.
authors.affiliation: Unit of Industrial Toxicology and Occupational Medicine, Faculty of Medicine, Catholic University of Louvain, Brussels, Belgium. hoet@toxi.ucl.ac.be
authors.forename: Perrine
authors.initials: P
authors.lastname: Hoet
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Buchet
authors.forename: Laurence
authors.initials: L
authors.lastname: Decerf
authors.forename: Benoît
authors.initials: B
authors.lastname: Lavalleye
authors.forename: Vincent
authors.initials: V
authors.lastname: Haufroid
authors.forename: Dominique
authors.initials: D
authors.lastname: Lison
mesh_terms: D000328:Adult; D002614:Chelating Agents / Q000493:pharmacokinetics; D003300:Copper / Q000652:urine; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D006801:Humans; D007854:Lead / Q000652:urine*; D007855:Lead Poisoning / Q000652:urine; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000652:urine; D004113:Succimer / Q000493:pharmacokinetics; D015032:Zinc / Q000652:urine
chemical_list: D002614:Chelating Agents; D004785:Environmental Pollutants; D007854:Lead; D003300:Copper; D004113:Succimer; D015032:Zinc