Abstract:
BACKGROUND. Spotted fever rickettsiosis, also known as tick bite fever (TBF), is a common infectious disease in South Africa (SA). Although
the diagnosis of TBF is often based on clinical grounds only, laboratory testing is important to confirm the diagnosis and can contribute to
case management in the light of a myriad of differential diagnoses, and in complicated cases.
OBJECTIVES. To report on the availability and scope of laboratory tests for investigating suspected cases of TBF in SA, and the outcome of an
inter-laboratory comparison (ILC) conducted for serological tests.
METHODS. A self-administered questionnaire was circulated to major pathology laboratories in SA to determine what TBF tests they offered
for TBF investigation. In addition, a clinical panel was provided to willing laboratories in order to perform an ILC of the serological tests.
RESULTS. Serological tests for TBF were available from five laboratories serving both the private and state medical sectors in SA. There was
no standardised testing platform or result interpretation across the different laboratories. Polymerase chain reaction (PCR) tests were less
frequently available, and not available to state-operated facilities. The outcome of the ILC indicated varied performance and interpretation
of serological results for TBF.
CONCLUSIONS. Laboratory investigation for TBF is routinely and widely available in SA. Both serological and PCR-based methods were
varied, and the lack of standardisation and interpretation of tests needs to be addressed to improve the overall quality of TBF diagnosis in
SA. The utility of ILC to identify problem areas in serological testing for TBF is highlighted, and laboratories in SA are encouraged to use
it to improve the quality of testing.
