title: In vivo digoxin-like immunoreactivity in mice and interference of Chinese medicine Danshen in serum digoxin measurement: elimination of interference by using a chemiluminescent assay.
abstract: BACKGROUND
  Danshen, a traditional Chinese medicine used in the management of cardiovascular diseases, is available without prescription in the US. Because Danshen is used to treat cardiovascular diseases, we studied the potential interference of Danshen with serum digoxin measurement using various immunoassays.
  
  
  METHODS
  Blood was collected 1 day before and then 1 and 2 h after feeding mice with Danshen. The apparent digitoxin activities were measured by the fluorescence polarization immunoassay (FPIA). We also added microliter amounts of Danshen extract to digoxin pools prepared from patients receiving digoxin. The digoxin concentrations were measured using the fluorescence polarization immunoassay (FPIA), microparticle enzyme immunoassay (MEIA) and chemiluminescent assay (CLIA). The observed values were compared with original values. We also fed mice with Danshen.
  
  
  RESULTS
  We observed measurable digoxin-like immunoreactivity in sera of mice after feeding with Danshen. We also observed falsely lower digoxin concentrations (negative interference) when MEIA was used for digoxin measurement. However, serum digoxin concentrations were falsely elevated with FPIA. We observed no interference of Danshen in serum digoxin measurement using the CLIA.
  
  
  CONCLUSIONS
  Danshen appears to contain digoxin-like immunoreactivity but does not interfere with serum digoxin measurement when CLIA was used.
authors.affiliation: Department of Pathology and Laboratory of Medicine, University of Texas, Houston Medical School, 6431 Fannin, MSB 2.292, Houston, TX 77030, USA. Amitava.Dasgupta@uth.tmc.edu
authors.forename: Amitava
authors.initials: A
authors.lastname: Dasgupta
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Actor
authors.forename: Margaret
authors.initials: M
authors.lastname: Olsen
authors.forename: Alice
authors.initials: A
authors.lastname: Wells
authors.forename: Pradip
authors.initials: P
authors.lastname: Datta
mesh_terms: D000818:Animals; D016477:Artifacts; D004077:Digoxin / Q000097:blood* / Q000276:immunology*; D016231:Fluorescence Polarization Immunoassay; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007124:Immunoenzyme Techniques; D008163:Luminescent Measurements; D008516:Medicine, Chinese Traditional; D051379:Mice; D010936:Plant Extracts / Q000097:blood* / Q000494:pharmacology; D027561:Salvia miltiorrhiza / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D004077:Digoxin