title: Evaluation of ELISA to detect Chlamydia trachomatis antigen in urine samples from arthritis patients.
abstract: OBJECTIVE
  To determine whether examination of urine samples using ELISA allows the detection of asymptomatic C. trachomatis infection in arthritis patients.
  
  
  METHODS
  The in vitro sensitivity of IDEIA Chlamydia ELISA to detect C. trachomatis in urine samples was determined by the investigation of serial dilutions of chlamydial elementary bodies. In a clinical study, urine samples from 402 consecutive arthritis patients (182 men and 220 women) in a tertiary care rheumatology clinic were examined for asymptomatic chlamydial infection by ELISA and the results were compared to culture and direct immunofluorescence assay (DFA, MicroTrak) of urogenital swabs.
  
  
  RESULTS
  The in vitro sensitivity of ELISA for detecting purified elementary bodies of C. trachomatis serovar K in urine was 60 infection forming units. Twenty-three of 402 arthritis patients (6%) had asymptomatic chlamydial infection as shown by DFA and culture from urogenital smears. The ELISA method identified only 3 of 17 swab-positive patients among 271 patients when urine specimens were collected during the clinical visit, while the assay detected all 6 swab-positive patients among 131 patients when first-voided early morning urine specimens were used (p < 0.001).
  
  
  CONCLUSIONS
  It is mandatory to examine only first voided early morning urine samples if ELISA is used instead of DFA or culture from urogenital swabs to detect asymptomatic chlamydial infection in arthritis patients.
authors.affiliation: Department of Internal Medicine, Hannover Medical School, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Wollenhaupt
authors.forename: F
authors.initials: F
authors.lastname: Hartmann
authors.forename: L
authors.initials: L
authors.lastname: Köhler
authors.forename: J G
authors.initials: JG
authors.lastname: Kuipers
authors.forename: E
authors.initials: E
authors.lastname: Nettelnbreker
authors.forename: M
authors.initials: M
authors.lastname: Frosch
authors.forename: H
authors.initials: H
authors.lastname: Zeidler
mesh_terms: D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology / Q000652:urine*; D016918:Arthritis, Reactive / Q000276:immunology / Q000382:microbiology* / Q000652:urine*; D002690:Chlamydia Infections / Q000652:urine*; D002692:Chlamydia trachomatis / Q000276:immunology; D003469:Culture; D003710:Demography; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D008070:Lipopolysaccharides / Q000032:analysis / Q000652:urine; D008297:Male; D008875:Middle Aged; D012216:Rheumatic Diseases / Q000150:complications / Q000175:diagnosis
chemical_list: D000942:Antigens, Bacterial; D008070:Lipopolysaccharides