Rapid Diagnostic Testing of Infectious Diseases

Lennox K. Archibald, MD, PhD


August 23, 2011

In This Article

Rapid Diagnostic Testing in Infectious Diseases

Despite myriad publications on rapid diagnostic testing (RDT) methodologies for infectious diseases, such testing has become neither commonplace nor an integral component of services offered by clinical microbiology laboratories in the United States. In the current era of managed care, the need for RDT is underscored by the emergence of virulent strains of influenza virus and novel pathogens such as the coronavirus that causes the severe acute respiratory syndrome (SARS), as well as the often grave consequences of healthcare-associated infections caused by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), Clostridium difficile, extended spectrum beta-lactamase (ESBL)-producing Klebsiella spp., and Mycobacterium tuberculosis.

Debate on the value of RDT has broadened and now encompasses infections caused by group A streptococcus, herpes simplex virus, West Nile virus, human immunodeficiency virus (HIV), and extremely drug-resistant tuberculosis (XDR-TB). More recently, the role of RDT in the routine diagnosis and prevention of syphilis and malaria has been discussed in some circles.

Prohibitive costs and doubtful cost-effectiveness of certain rapid tests are typically blamed for the unavailability of RDT.[1] To be cost-effective, a test must have sufficient diagnostic value, and its use must be limited to the organisms most likely to be clinically relevant, and to circumstances in which earlier diagnosis would likely have an impact on patient management.[2,3] "Clinical value" encompasses many questions:

  • Why was the test requested?

  • Will the result aid or alter patient management?

  • Would a simpler or cheaper test provide the same information?

  • Will the use of a specific RDT lead to improved understanding of the medical condition?

  • Could we do without RDT for the clinical situation under consideration?

  • Is the specific RDT test of public health or clinical importance?[1]

  • Is the test reliable?[4]

Even if the RDT is affordable, will it be cost-effective and sustainable in the long term? This is particularly relevant for less-developed countries, and even for countries such as the United States, where, in a recent trend, healthcare facilities (including academic centers) are purchasing microbiology services from private, rather than hospital-based, laboratories.


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