title: Analytical interference of quinolone antibiotics and quinine derived drugs on urinary protein determined by reagent strips and the pyrogallol red-molybdate protein assay.
abstract: OBJECTIVE
  To investigate the analytical interference of drugs in urinary protein and to estimate the lowest interfering concentrations.
  
  
  METHODS
  Drug supplemented urine samples were compared to the control with two reagent strips and the total protein was determined using Pyrogallol Red-Molybdate (PRM).
  
  
  RESULTS
  False-positive interferences occurred with Multistix 10 SG for hydroxychloroquine, levofloxacin and ofloxacin. No interference was observed with Combur 10 Test M. Statistically significant false-positive interferences were observed in the PRM assay with all tested drugs, and lowest interfering concentrations were mostly above estimated therapeutic concentrations. The PRM assay "confirmed" the results of the Multistix dipstick, so a real proteinuria could be presumed from the double analytical interference.
  
  
  CONCLUSIONS
  This is the first report of analytical interference by quinolone and quinine derivatives in the PRM assay. Special attention to patients using these drugs is needed to minimize errors in the interpretation of urinary protein results.
authors.affiliation: Clinical Laboratory Analysis, University Hospital, Federal University of Santa Catarina, Campus Trindade, 88040-970, Florianópolis, Santa Catarina, Brazil.
authors.forename: Adriana Scotti
authors.initials: AS
authors.lastname: da Silva
authors.forename: Miriam
authors.initials: M
authors.lastname: Falkenberg
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents; D016022:Case-Control Studies; D002624:Chemistry, Clinical / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008982:Molybdenum / Q000032:analysis; D011507:Proteinuria / Q000652:urine*; D011748:Pyrogallol / Q000031:analogs & derivatives; D011803:Quinine; D015363:Quinolones; D011934:Reagent Strips; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones; D011934:Reagent Strips; D011748:Pyrogallol; C044659:molybdate; D008982:Molybdenum; D011803:Quinine