title: Interpretation of laboratory detection trends for Chlamydia trachomatis and Neisseria gonorrhoeae: Manitoba, Canada, 2000-2012.
abstract: OBJECTIVE
  Increases in case numbers for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) have been noted on a global level. This study analysed 13 years of testing data to better understand case detection trends over time.
  
  
  METHODS
  Data consisted of all nucleic acid probe and nucleic acid amplification diagnostic testing for CT and NG for the population of Manitoba, Canada (1.2 million); January 2000 to December 2012. Logistic regression models were used to analyse ORs associated with positive CT and NG tests by year. Included in the model as predictor variables were test type, specimen type, patient age and residence location.
  
  
  RESULTS
  For both male and female CT results, unadjusted OR by year mimicked absolute case counts, reflecting a general increase over time in case counts. Adjustment for laboratory-related variables altered this relationship such that a general decline in the odds of identifying a CT case over time was evident. For both male and female NG results, adjustment for laboratory and demographic variables altered the OR associated with each year, but to a lesser extent than for CT.
  
  
  CONCLUSIONS
  Temporal trends associated with CT case numbers should be interpreted after controlling, at a minimum, for the influence of laboratory-related variables. Interpretation of NG trends is feasible using only the number of reported NG cases.
authors.affiliation: Cadham Provincial Laboratory, Province of Manitoba, Winnipeg, Canada.
authors.forename: John L
authors.initials: JL
authors.lastname: Wylie
authors.affiliation: Cadham Provincial Laboratory, Province of Manitoba, Winnipeg, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Van Caeseele
mesh_terms: D002690:Chlamydia Infections / Q000175:diagnosis* / Q000453:epidemiology; D004269:DNA, Bacterial; D003625:Data Collection; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D021141:Nucleic Acid Amplification Techniques; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D004269:DNA, Bacterial
keywords: CHLAMYDIA TRACHOMATIS; DNA AMPLIFICATION; DNA PROBE; NEISSERIA GONORRHOEA; PUBLIC HEALTH