A Survey of Pertussis Diagnostics in the US

Background:
Diagnostic testing methods for pertussis include culture, polymerase chain reaction (PCR), direct fluorescent antibody (DFA) and serology. Culture is considered the gold standard, but surveillance data indicate PCR is quickly becoming the most common test for diagnosing pertussis in the US and anecdotal evidence suggests many labs are abandoning culture because of suboptimal performance characteristics and associated costs. Concern over the implementation of PCR prior to thorough standardization and the variable clinical sensitivity and specificity of PCR prompted a national survey to better understand current practices in pertussis diagnostics.

Setting:
N/A

Population:
A broad convenience sample of commercial, hospital, and public health laboratories reported to be performing diagnostic testing for respiratory pathogens was identified and invited to participate.

Project Description:
Invitations to participate in an electronic survey about pertussis testing were sent by mail and email. The survey collected information about the diagnostic methods used for pertussis, the approximate volume of tests performed in the previous year and the percent of positive results.

Results/Lessons Learned:
Responses were received from 368 labs. Overall, 20% of all responding labs (13%, 32% and 87% of responding hospital, commercial, and public health laboratories, respectively) reported performing PCR for pertussis. Isolation by culture was done at 21% of responding labs, but among those doing PCR, only 35% were also performing culture. DFA and serologic testing for pertussis was being done by 4% and 3% of responding labs, respectively. Of those doing PCR testing, 60% tested 101-1000 samples in the previous year and 7% tested >1000 samples in the previous year. In conclusion, these results suggest that most of the pertussis testing is being done at large commercial or public health laboratories and the majority of these laboratories are not currently using culture to isolate the organism.