Figure 2 is a bar-chart of paediatric paediatric-related intensive care unit (ICU) admissions by test method and year, between 1997 and 2013 in Queensland Australia. In the years 1997-1998, the majority of admissions did not have a diagnostic test found. Only three admissions (in 1998, 1999 and 2001) had non-polymerase chain reaction (PCR) tests done. From 2000 onwards, PCR was used almost exclusively to test pertussis-related ICU admissions.